Provided by: libstrongswan_5.8.2-1ubuntu3.6_amd64 
NAME
strongswan.conf - strongSwan configuration file
DESCRIPTION
While the ipsec.conf(5) configuration file is well suited to define IPsec related
configuration parameters, it is not useful for other strongSwan applications to read
options from this file. The file is hard to parse and only ipsec starter is capable of
doing so. As the number of components of the strongSwan project is continually growing, a
more flexible configuration file was needed, one that is easy to extend and can be used by
all components. With strongSwan 4.2.1 strongswan.conf(5) was introduced which meets these
requirements.
SYNTAX
The format of the strongswan.conf file consists of hierarchical sections and a list of
key/value pairs in each section. Each section has a name, followed by C-Style curly
brackets defining the section body. Each section body contains a set of subsections and
key/value pairs:
settings := (section|keyvalue)*
section := name { settings }
keyvalue := key = value\n
Values must be terminated by a newline.
Comments are possible using the #-character.
Section names and keys may contain any printable character except:
. , : { } = " # \n \t space
An example file in this format might look like this:
a = b
section-one {
somevalue = asdf
subsection {
othervalue = xxx
}
# yei, a comment
yetanother = zz
}
section-two {
x = 12
}
Indentation is optional, you may use tabs or spaces.
REFERENCING OTHER SECTIONS
It is possible to inherit settings and sections from another section. This feature is
mainly useful in swanctl.conf (which uses the same file format). The syntax is as
follows:
section := name : references { settings }
references := absname[, absname]*
absname := name[.name]*
All key/value pairs and all subsections of the referenced sections will be inherited by
the section that references them via their absolute name. Values may be overridden in the
section or any of its sub-sections (use an empty assignment to clear a value so its
default value, if any, will apply). It is currently not possible to limit the inclusion
level or clear/remove inherited sub-sections.
If the order is important (e.g. for auth rounds in a connection, if round is not used), it
should be noted that inherited settings/sections will follow those defined in the current
section (if multiple sections are referenced, their settings are enumerated left to
right).
References are evaluated dynamically at runtime, so referring to sections later in the
config file or included via other files is no problem.
Here is an example of how this might look like:
conn-defaults {
# default settings for all conns (e.g. a cert, or IP pools)
}
eap-defaults {
# defaults if eap is used (e.g. a remote auth round)
}
child-defaults {
# defaults for child configs (e.g. traffic selectors)
}
connections {
conn-a : conn-defaults, eap-defaults {
# set/override stuff specific to this connection
children {
child-a : child-defaults {
# set/override stuff specific to this child
}
}
}
conn-b : conn-defaults {
# set/override stuff specific to this connection
children {
child-b : child-defaults {
# set/override stuff specific to this child
}
}
}
conn-c : connections.conn-a {
# everything is inherited, including everything conn-a
# already inherits from the sections it and its
# sub-section reference
}
}
INCLUDING FILES
Using the include statement it is possible to include other files into strongswan.conf,
e.g.
include /some/path/*.conf
If the file name is not an absolute path, it is considered to be relative to the directory
of the file containing the include statement. The file name may include shell wildcards
(see sh(1)). Also, such inclusions can be nested.
Sections loaded from included files extend previously loaded sections; already existing
values are replaced. It is important to note that settings are added relative to the
section the include statement is in.
As an example, the following three files result in the same final config as the one given
above:
a = b
section-one {
somevalue = before include
include include.conf
}
include other.conf
include.conf:
# settings loaded from this file are added to section-one
# the following replaces the previous value
somevalue = asdf
subsection {
othervalue = yyy
}
yetanother = zz
other.conf:
# this extends section-one and subsection
section-one {
subsection {
# this replaces the previous value
othervalue = xxx
}
}
section-two {
x = 12
}
READING VALUES
Values are accessed using a dot-separated section list and a key. With reference to the
example above, accessing section-one.subsection.othervalue will return xxx.
DEFINED KEYS
The following keys are currently defined (using dot notation). The default value (if any)
is listed in brackets after the key.
aikgen.load []
Plugins to load in ipsec aikgen tool.
attest.database []
File measurement information database URI. If it contains a password, make sure to
adjust the permissions of the config file accordingly.
attest.load []
Plugins to load in ipsec attest tool.
charon
Options for the charon IKE daemon.
Note: Many of the options in this section also apply to charon-cmd and other charon
derivatives. Just use their respective name (e.g. charon-cmd instead of charon).
For many options defaults can be defined in the libstrongswan section.
charon.accept_unencrypted_mainmode_messages [no]
Accept unencrypted ID and HASH payloads in IKEv1 Main Mode.
Some implementations send the third Main Mode message unencrypted, probably to find
the PSKs for the specified ID for authentication. This is very similar to
Aggressive Mode, and has the same security implications: A passive attacker can
sniff the negotiated Identity, and start brute forcing the PSK using the HASH
payload.
It is recommended to keep this option to no, unless you know exactly what the
implications are and require compatibility to such devices (for example, some
SonicWall boxes).
charon.block_threshold [5]
Maximum number of half-open IKE_SAs for a single peer IP.
charon.cache_crls [no]
Whether Certificate Revocation Lists (CRLs) fetched via HTTP or LDAP should be
saved under a unique file name derived from the public key of the Certification
Authority (CA) to /etc/ipsec.d/crls (stroke) or /etc/swanctl/x509crl (vici),
respectively.
charon.cert_cache [yes]
Whether relations in validated certificate chains should be cached in memory.
charon.cisco_unity [no]
Send Cisco Unity vendor ID payload (IKEv1 only).
charon.close_ike_on_child_failure [no]
Close the IKE_SA if setup of the CHILD_SA along with IKE_AUTH failed.
charon.cookie_threshold [10]
Number of half-open IKE_SAs that activate the cookie mechanism.
charon.crypto_test.bench [no]
Benchmark crypto algorithms and order them by efficiency.
charon.crypto_test.bench_size [1024]
Buffer size used for crypto benchmark.
charon.crypto_test.bench_time [50]
Time in ms during which crypto algorithm performance is measured.
charon.crypto_test.on_add [no]
Test crypto algorithms during registration (requires test vectors provided by the
test-vectors plugin).
charon.crypto_test.on_create [no]
Test crypto algorithms on each crypto primitive instantiation.
charon.crypto_test.required [no]
Strictly require at least one test vector to enable an algorithm.
charon.crypto_test.rng_true [no]
Whether to test RNG with TRUE quality; requires a lot of entropy.
charon.delete_rekeyed [no]
Delete CHILD_SAs right after they got successfully rekeyed (IKEv1 only). Reduces
the number of stale CHILD_SAs in scenarios with a lot of rekeyings. However, this
might cause problems with implementations that continue to use rekeyed SAs until
they expire.
charon.delete_rekeyed_delay [5]
Delay in seconds until inbound IPsec SAs are deleted after rekeyings (IKEv2 only).
To process delayed packets the inbound part of a CHILD_SA is kept installed up to
the configured number of seconds after it got replaced during a rekeying. If set to
0 the CHILD_SA will be kept installed until it expires (if no lifetime is set it
will be destroyed immediately).
charon.dh_exponent_ansi_x9_42 [yes]
Use ANSI X9.42 DH exponent size or optimum size matched to cryptographic strength.
charon.dlopen_use_rtld_now [no]
Use RTLD_NOW with dlopen when loading plugins and IMV/IMCs to reveal missing
symbols immediately.
charon.dns1 []
DNS server assigned to peer via configuration payload (CP).
charon.dns2 []
DNS server assigned to peer via configuration payload (CP).
charon.dos_protection [yes]
Enable Denial of Service protection using cookies and aggressiveness checks.
charon.ecp_x_coordinate_only [yes]
Compliance with the errata for RFC 4753.
charon.filelog
Section to define file loggers, see LOGGER CONFIGURATION in strongswan.conf(5).
charon.filelog.<name>
<name> may be the full path to the log file if it only contains characters
permitted in section names. Is ignored if path is specified.
charon.filelog.<name>.<subsystem> [<default>]
Loglevel for a specific subsystem.
charon.filelog.<name>.append [yes]
If this option is enabled log entries are appended to the existing file.
charon.filelog.<name>.default [1]
Specifies the default loglevel to be used for subsystems for which no specific
loglevel is defined.
charon.filelog.<name>.flush_line [no]
Enabling this option disables block buffering and enables line buffering.
charon.filelog.<name>.ike_name [no]
Prefix each log entry with the connection name and a unique numerical identifier
for each IKE_SA.
charon.filelog.<name>.path []
Optional path to the log file. Overrides the section name. Must be used if the path
contains characters that aren't allowed in section names.
charon.filelog.<name>.time_add_ms [no]
Adds the milliseconds within the current second after the timestamp (separated by a
dot, so time_format should end with %S or %T).
charon.filelog.<name>.time_format []
Prefix each log entry with a timestamp. The option accepts a format string as
passed to strftime(3).
charon.flush_auth_cfg [no]
If enabled objects used during authentication (certificates, identities etc.) are
released to free memory once an IKE_SA is established. Enabling this might conflict
with plugins that later need access to e.g. the used certificates.
charon.follow_redirects [yes]
Whether to follow IKEv2 redirects (RFC 5685).
charon.fragment_size [1280]
Maximum size (complete IP datagram size in bytes) of a sent IKE fragment when using
proprietary IKEv1 or standardized IKEv2 fragmentation, defaults to 1280 (use 0 for
address family specific default values, which uses a lower value for IPv4). If
specified this limit is used for both IPv4 and IPv6.
charon.group []
Name of the group the daemon changes to after startup.
charon.half_open_timeout [30]
Timeout in seconds for connecting IKE_SAs (also see IKE_SA_INIT DROPPING).
charon.hash_and_url [no]
Enable hash and URL support.
charon.host_resolver.max_threads [3]
Maximum number of concurrent resolver threads (they are terminated if unused).
charon.host_resolver.min_threads [0]
Minimum number of resolver threads to keep around.
charon.i_dont_care_about_security_and_use_aggressive_mode_psk [no]
If enabled responders are allowed to use IKEv1 Aggressive Mode with pre-shared
keys, which is discouraged due to security concerns (offline attacks on the openly
transmitted hash of the PSK).
charon.ignore_acquire_ts [no]
If this is disabled the traffic selectors from the kernel's acquire events, which
are derived from the triggering packet, are prepended to the traffic selectors from
the configuration for IKEv2 connection. By enabling this, such specific traffic
selectors will be ignored and only the ones in the config will be sent. This always
happens for IKEv1 connections as the protocol only supports one set of traffic
selectors per CHILD_SA.
charon.ignore_routing_tables []
A space-separated list of routing tables to be excluded from route lookups.
charon.ikesa_limit [0]
Maximum number of IKE_SAs that can be established at the same time before new
connection attempts are blocked.
charon.ikesa_table_segments [1]
Number of exclusively locked segments in the hash table.
charon.ikesa_table_size [1]
Size of the IKE_SA hash table.
charon.imcv
Defaults for options in this section can be configured in the libimcv section.
charon.imcv.assessment_result [yes]
Whether IMVs send a standard IETF Assessment Result attribute.
charon.imcv.database []
Global IMV policy database URI. If it contains a password, make sure to adjust the
permissions of the config file accordingly.
charon.imcv.os_info.default_password_enabled [no]
Manually set whether a default password is enabled
charon.imcv.os_info.name []
Manually set the name of the client OS (e.g. Ubuntu).
charon.imcv.os_info.version []
Manually set the version of the client OS (e.g. 12.04 i686).
charon.imcv.policy_script [ipsec _imv_policy]
Script called for each TNC connection to generate IMV policies.
charon.inactivity_close_ike [no]
Whether to close IKE_SA if the only CHILD_SA closed due to inactivity.
charon.init_limit_half_open [0]
Limit new connections based on the current number of half open IKE_SAs, see
IKE_SA_INIT DROPPING in strongswan.conf(5).
charon.init_limit_job_load [0]
Limit new connections based on the number of jobs currently queued for processing
(see IKE_SA_INIT DROPPING).
charon.initiator_only [no]
Causes charon daemon to ignore IKE initiation requests.
charon.install_routes [yes]
Install routes into a separate routing table for established IPsec tunnels.
charon.install_virtual_ip [yes]
Install virtual IP addresses.
charon.install_virtual_ip_on []
The name of the interface on which virtual IP addresses should be installed. If not
specified the addresses will be installed on the outbound interface.
charon.integrity_test [no]
Check daemon, libstrongswan and plugin integrity at startup.
charon.interfaces_ignore []
A comma-separated list of network interfaces that should be ignored, if
interfaces_use is specified this option has no effect.
charon.interfaces_use []
A comma-separated list of network interfaces that should be used by charon. All
other interfaces are ignored.
charon.keep_alive [20s]
NAT keep alive interval.
charon.leak_detective.detailed [yes]
Includes source file names and line numbers in leak detective output.
charon.leak_detective.usage_threshold [10240]
Threshold in bytes for leaks to be reported (0 to report all).
charon.leak_detective.usage_threshold_count [0]
Threshold in number of allocations for leaks to be reported (0 to report all).
charon.load []
Plugins to load in the IKE daemon charon.
charon.load_modular [no]
If enabled, the list of plugins to load is determined via the value of the
charon.plugins.<name>.load options. In addition to a simple boolean flag that
option may take an integer value indicating the priority of a plugin, which would
influence the order of a plugin in the plugin list (the default is 1). If two
plugins have the same priority their order in the default plugin list is preserved.
Enabled plugins not found in that list are ordered alphabetically before other
plugins with the same priority.
charon.make_before_break [no]
Initiate IKEv2 reauthentication with a make-before-break instead of a
break-before-make scheme. Make-before-break uses overlapping IKE and CHILD_SA
during reauthentication by first recreating all new SAs before deleting the old
ones. This behavior can be beneficial to avoid connectivity gaps during
reauthentication, but requires support for overlapping SAs by the peer. strongSwan
can handle such overlapping SAs since version 5.3.0.
charon.max_ikev1_exchanges [3]
Maximum number of IKEv1 phase 2 exchanges per IKE_SA to keep state about and track
concurrently.
charon.max_packet [10000]
Maximum packet size accepted by charon.
charon.multiple_authentication [yes]
Enable multiple authentication exchanges (RFC 4739).
charon.nbns1 []
WINS servers assigned to peer via configuration payload (CP).
charon.nbns2 []
WINS servers assigned to peer via configuration payload (CP).
charon.plugin.ha.buflen [2048]
Buffer size for received HA messages. For IKEv1 the public DH factors are also
transmitted so depending on the DH group the HA messages can get quite big (the
default should be fine up to modp4096).
charon.plugins.addrblock.strict [yes]
If set to yes, a subject certificate without an addrblock extension is rejected if
the issuer certificate has such an addrblock extension. If set to no, subject
certificates issued without the addrblock extension are accepted without any
traffic selector checks and no policy is enforced by the plugin.
charon.plugins.android_log.loglevel [1]
Loglevel for logging to Android specific logger.
charon.plugins.attr
Section to specify arbitrary attributes that are assigned to a peer via
configuration payload (CP).
charon.plugins.attr.<attr> []
<attr> can be either address, netmask, dns, nbns, dhcp, subnet, split-include,
split-exclude or the numeric identifier of the attribute type. The assigned value
can be an IPv4/IPv6 address, a subnet in CIDR notation or an arbitrary value
depending on the attribute type. For some attribute types multiple values may be
specified as a comma separated list.
charon.plugins.attr-sql.crash_recovery [yes]
Release all online leases during startup. Disable this to share the DB between
multiple VPN gateways.
charon.plugins.attr-sql.database []
Database URI for attr-sql plugin used by charon. If it contains a password, make
sure to adjust the permissions of the config file accordingly.
charon.plugins.attr-sql.lease_history [yes]
Enable logging of SQL IP pool leases.
charon.plugins.bliss.use_bliss_b [yes]
Use the enhanced BLISS-B key generation and signature algorithm.
charon.plugins.bypass-lan.interfaces_ignore []
A comma-separated list of network interfaces for which connected subnets should be
ignored, if interfaces_use is specified this option has no effect.
charon.plugins.bypass-lan.interfaces_use []
A comma-separated list of network interfaces for which connected subnets should be
considered. All other interfaces are ignored.
charon.plugins.certexpire.csv.cron []
Cron style string specifying CSV export times.
charon.plugins.certexpire.csv.empty_string []
String to use in empty intermediate CA fields.
charon.plugins.certexpire.csv.fixed_fields [yes]
Use a fixed intermediate CA field count.
charon.plugins.certexpire.csv.force [yes]
Force export of all trustchains we have a private key for.
charon.plugins.certexpire.csv.format [%d:%m:%Y]
strftime(3) format string to export expiration dates as.
charon.plugins.certexpire.csv.local []
strftime(3) format string for the CSV file name to export local certificates to.
charon.plugins.certexpire.csv.remote []
strftime(3) format string for the CSV file name to export remote certificates to.
charon.plugins.certexpire.csv.separator [,]
CSV field separator.
charon.plugins.coupling.file []
File to store coupling list to.
charon.plugins.coupling.hash [sha1]
Hashing algorithm to fingerprint coupled certificates.
charon.plugins.coupling.max [1]
Maximum number of coupling entries to create.
charon.plugins.curl.redir [-1]
Maximum number of redirects followed by the plugin, set to 0 to disable following
redirects, set to -1 for no limit.
charon.plugins.dhcp.force_server_address [no]
Always use the configured server address. This might be helpful if the DHCP server
runs on the same host as strongSwan, and the DHCP daemon does not listen on the
loopback interface. In that case the server cannot be reached via unicast (or even
255.255.255.255) as that would be routed via loopback. Setting this option to yes
and configuring the local broadcast address (e.g. 192.168.0.255) as server address
might work.
charon.plugins.dhcp.identity_lease [no]
Derive user-defined MAC address from hash of IKE identity and send client identity
DHCP option.
charon.plugins.dhcp.interface []
Interface name the plugin uses for address allocation. The default is to bind to
any (0.0.0.0) and let the system decide which way to route the packets to the DHCP
server.
charon.plugins.dhcp.server [255.255.255.255]
DHCP server unicast or broadcast IP address.
charon.plugins.dhcp.use_server_port [no]
Use the DHCP server port (67) as source port, instead of the DHCP client port (68),
when a unicast server address is configured and the plugin acts as relay agent.
When replying in this mode the DHCP server will always send packets to the DHCP
server port and if no process binds that port an ICMP port unreachables will be
sent back, which might be problematic for some DHCP servers. To avoid that,
enabling this option will cause the plugin to bind the DHCP server port to send its
requests when acting as relay agent. This is not necessary if a DHCP server is
already running on the same host and might even cause conflicts (and since the
server port is already bound, ICMPs should not be an issue).
charon.plugins.dnscert.enable [no]
Enable fetching of CERT RRs via DNS.
charon.plugins.drbg.max_drbg_requests [4294967294]
Number of pseudo-random bit requests from the DRBG before an automatic reseeding
occurs.
charon.plugins.duplicheck.enable [yes]
Enable duplicheck plugin (if loaded).
charon.plugins.duplicheck.socket [unix://${piddir}/charon.dck]
Socket provided by the duplicheck plugin.
charon.plugins.eap-aka.request_identity [yes]
charon.plugins.eap-aka-3gpp.seq_check []
Enable to activate sequence check of the AKA SQN values in order to trigger resync
cycles.
charon.plugins.eap-aka-3gpp2.seq_check []
Enable to activate sequence check of the AKA SQN values in order to trigger resync
cycles.
charon.plugins.eap-dynamic.prefer_user [no]
If enabled the EAP methods proposed in an EAP-Nak message sent by the peer are
preferred over the methods registered locally.
charon.plugins.eap-dynamic.preferred []
The preferred EAP method(s) to be used. If it is not given the first registered
method will be used initially. If a comma separated list is given the methods are
tried in the given order before trying the rest of the registered methods.
charon.plugins.eap-gtc.backend [pam]
XAuth backend to be used for credential verification.
charon.plugins.eap-peap.fragment_size [1024]
Maximum size of an EAP-PEAP packet.
charon.plugins.eap-peap.include_length [no]
Include length in non-fragmented EAP-PEAP packets.
charon.plugins.eap-peap.max_message_count [32]
Maximum number of processed EAP-PEAP packets (0 = no limit).
charon.plugins.eap-peap.phase2_method [mschapv2]
Phase2 EAP client authentication method.
charon.plugins.eap-peap.phase2_piggyback [no]
Phase2 EAP Identity request piggybacked by server onto TLS Finished message.
charon.plugins.eap-peap.phase2_tnc [no]
Start phase2 EAP TNC protocol after successful client authentication.
charon.plugins.eap-peap.request_peer_auth [no]
Request peer authentication based on a client certificate.
charon.plugins.eap-radius.accounting [no]
Send RADIUS accounting information to RADIUS servers.
charon.plugins.eap-radius.accounting_close_on_timeout [yes]
Close the IKE_SA if there is a timeout during interim RADIUS accounting updates.
charon.plugins.eap-radius.accounting_interval [0]
Interval in seconds for interim RADIUS accounting updates, if not specified by the
RADIUS server in the Access-Accept message.
charon.plugins.eap-radius.accounting_requires_vip [no]
If enabled, accounting is disabled unless an IKE_SA has at least one virtual IP.
Only for IKEv2, for IKEv1 a virtual IP is strictly necessary.
charon.plugins.eap-radius.accounting_send_class [no]
If enabled, adds the Class attributes received in Access-Accept message to the
RADIUS accounting messages.
charon.plugins.eap-radius.class_group [no]
Use the class attribute sent in the RADIUS-Accept message as group membership
information that is compared to the groups specified in the rightgroups option in
ipsec.conf(5).
charon.plugins.eap-radius.close_all_on_timeout [no]
Closes all IKE_SAs if communication with the RADIUS server times out. If it is not
set only the current IKE_SA is closed.
charon.plugins.eap-radius.dae.enable [no]
Enables support for the Dynamic Authorization Extension (RFC 5176).
charon.plugins.eap-radius.dae.listen [0.0.0.0]
Address to listen for DAE messages from the RADIUS server.
charon.plugins.eap-radius.dae.port [3799]
Port to listen for DAE requests.
charon.plugins.eap-radius.dae.secret []
Shared secret used to verify/sign DAE messages. If set, make sure to adjust the
permissions of the config file accordingly.
charon.plugins.eap-radius.eap_start [no]
Send EAP-Start instead of EAP-Identity to start RADIUS conversation.
charon.plugins.eap-radius.filter_id [no]
If the RADIUS tunnel_type attribute with value ESP is received, use the filter_id
attribute sent in the RADIUS-Accept message as group membership information that is
compared to the groups specified in the rightgroups option in ipsec.conf(5).
charon.plugins.eap-radius.forward.ike_to_radius []
RADIUS attributes to be forwarded from IKEv2 to RADIUS (can be defined by name or
attribute number, a colon can be used to specify vendor-specific attributes, e.g.
Reply-Message, or 11, or 36906:12).
charon.plugins.eap-radius.forward.radius_to_ike []
Same as charon.plugins.eap-radius.forward.ike_to_radius but from RADIUS to IKEv2, a
strongSwan specific private notify (40969) is used to transmit the attributes.
charon.plugins.eap-radius.id_prefix []
Prefix to EAP-Identity, some AAA servers use a IMSI prefix to select the EAP
method.
charon.plugins.eap-radius.nas_identifier [strongSwan]
NAS-Identifier to include in RADIUS messages.
charon.plugins.eap-radius.port [1812]
Port of RADIUS server (authentication).
charon.plugins.eap-radius.retransmit_base [1.4]
Base to use for calculating exponential back off.
charon.plugins.eap-radius.retransmit_timeout [2.0]
Timeout in seconds before sending first retransmit.
charon.plugins.eap-radius.retransmit_tries [4]
Number of times to retransmit a packet before giving up.
charon.plugins.eap-radius.secret []
Shared secret between RADIUS and NAS. If set, make sure to adjust the permissions
of the config file accordingly.
charon.plugins.eap-radius.server []
IP/Hostname of RADIUS server.
charon.plugins.eap-radius.servers
Section to specify multiple RADIUS servers. The nas_identifier, secret, sockets and
port (or auth_port) options can be specified for each server. A server's
IP/Hostname can be configured using the address option. The acct_port [1813]
option can be used to specify the port used for RADIUS accounting. For each RADIUS
server a priority can be specified using the preference [0] option. The
retransmission time for each server can set set using retransmit_base,
retransmit_timeout and retransmit_tries.
charon.plugins.eap-radius.sockets [1]
Number of sockets (ports) to use, increase for high load.
charon.plugins.eap-radius.station_id_with_port [yes]
Whether to include the UDP port in the Called- and Calling-Station-Id RADIUS
attributes.
charon.plugins.eap-radius.xauth
Section to configure multiple XAuth authentication rounds via RADIUS. The
subsections define so called authentication profiles with arbitrary names. In each
profile section one or more XAuth types can be configured, with an assigned
message. For each type a separate XAuth exchange will be initiated and all replies
get concatenated into the User-Password attribute, which then gets verified over
RADIUS.
Available XAuth types are password, passcode, nextpin, and answer. This type is
not relevant to strongSwan or the AAA server, but the client may show a different
dialog (along with the configured message).
To use the configured profiles, they have to be configured in the respective
connection in ipsec.conf(5) by appending the profile name, separated by a colon, to
the xauth-radius XAauth backend configuration in rightauth or rightauth2, for
instance, rightauth2=xauth-radius:profile.
charon.plugins.eap-sim.request_identity [yes]
charon.plugins.eap-simaka-sql.database []
charon.plugins.eap-simaka-sql.remove_used [no]
charon.plugins.eap-tls.fragment_size [1024]
Maximum size of an EAP-TLS packet.
charon.plugins.eap-tls.include_length [yes]
Include length in non-fragmented EAP-TLS packets.
charon.plugins.eap-tls.max_message_count [32]
Maximum number of processed EAP-TLS packets (0 = no limit).
charon.plugins.eap-tnc.max_message_count [10]
Maximum number of processed EAP-TNC packets (0 = no limit).
charon.plugins.eap-tnc.protocol [tnccs-2.0]
IF-TNCCS protocol version to be used (tnccs-1.1, tnccs-2.0, tnccs-dynamic).
charon.plugins.eap-ttls.fragment_size [1024]
Maximum size of an EAP-TTLS packet.
charon.plugins.eap-ttls.include_length [yes]
Include length in non-fragmented EAP-TTLS packets.
charon.plugins.eap-ttls.max_message_count [32]
Maximum number of processed EAP-TTLS packets (0 = no limit).
charon.plugins.eap-ttls.phase2_method [md5]
Phase2 EAP client authentication method.
charon.plugins.eap-ttls.phase2_piggyback [no]
Phase2 EAP Identity request piggybacked by server onto TLS Finished message.
charon.plugins.eap-ttls.phase2_tnc [no]
Start phase2 EAP TNC protocol after successful client authentication.
charon.plugins.eap-ttls.phase2_tnc_method [pt]
Phase2 EAP TNC transport protocol (pt as IETF standard or legacy tnc)
charon.plugins.eap-ttls.request_peer_auth [no]
Request peer authentication based on a client certificate.
charon.plugins.error-notify.socket [unix://${piddir}/charon.enfy]
Socket provided by the error-notify plugin.
charon.plugins.ext-auth.script []
Command to pass to the system shell for peer authorization. Authorization is
considered successful if the command executes normally with an exit code of zero.
For all other exit codes IKE_SA authorization is rejected.
The following environment variables get passed to the script: IKE_UNIQUE_ID: The
IKE_SA numerical unique identifier. IKE_NAME: The peer configuration connection
name. IKE_LOCAL_HOST: Local IKE IP address. IKE_REMOTE_HOST: Remote IKE IP
address. IKE_LOCAL_ID: Local IKE identity. IKE_REMOTE_ID: Remote IKE identity.
IKE_REMOTE_EAP_ID: Remote EAP or XAuth identity, if used.
charon.plugins.forecast.groups
[224.0.0.1,224.0.0.22,224.0.0.251,224.0.0.252,239.255.255.250]
Comma separated list of multicast groups to join locally. The local host receives
and forwards packets in the local LAN for joined multicast groups only. Packets
matching the list of multicast groups get forwarded to connected clients. The
default group includes host multicasts, IGMP, mDNS, LLMNR and SSDP/WS-Discovery,
and is usually a good choice for Windows clients.
charon.plugins.forecast.interface []
Name of the local interface to listen for broadcasts messages to forward. If no
interface is configured, the first usable interface is used, which is usually just
fine for single-homed hosts. If your host has multiple interfaces, set this option
to the local LAN interface you want to forward broadcasts from/to.
charon.plugins.forecast.reinject []
Comma separated list of CHILD_SA configuration names for which to perform
multi/broadcast reinjection. For clients connecting over such a configuration, any
multi/broadcast received over the tunnel gets reinjected to all active tunnels.
This makes the broadcasts visible to other peers, and for examples allows clients
to see others shares. If disabled, multi/broadcast messages received over a tunnel
are injected to the local network only, but not to other IPsec clients.
charon.plugins.gcrypt.quick_random [no]
Use faster random numbers in gcrypt; for testing only, produces weak keys!
charon.plugins.ha.autobalance [0]
Interval in seconds to automatically balance handled segments between nodes. Set to
0 to disable.
charon.plugins.ha.fifo_interface [yes]
charon.plugins.ha.heartbeat_delay [1000]
charon.plugins.ha.heartbeat_timeout [2100]
charon.plugins.ha.local []
charon.plugins.ha.monitor [yes]
charon.plugins.ha.pools []
charon.plugins.ha.remote []
charon.plugins.ha.resync [yes]
charon.plugins.ha.secret []
charon.plugins.ha.segment_count [1]
charon.plugins.ipseckey.enable [no]
Enable fetching of IPSECKEY RRs via DNS.
charon.plugins.kernel-libipsec.allow_peer_ts [no]
Allow that the remote traffic selector equals the IKE peer. The route installed for
such traffic (via TUN device) usually prevents further IKE traffic. The fwmark
options for the kernel-netlink and socket-default plugins can be used to circumvent
that problem.
charon.plugins.kernel-netlink.buflen [<min(PAGE_SIZE, 8192)>]
Buffer size for received Netlink messages.
charon.plugins.kernel-netlink.force_receive_buffer_size [no]
If the maximum Netlink socket receive buffer in bytes set by receive_buffer_size
exceeds the system-wide maximum from /proc/sys/net/core/rmem_max, this option can
be used to override the limit. Enabling this option requires special privileges
(CAP_NET_ADMIN).
charon.plugins.kernel-netlink.fwmark []
Firewall mark to set on the routing rule that directs traffic to our routing table.
The format is [!]mark[/mask], where the optional exclamation mark inverts the
meaning (i.e. the rule only applies to packets that don't match the mark).
charon.plugins.kernel-netlink.hw_offload_feature_interface [lo]
If the kernel supports hardware offloading, the plugin needs to find the feature
flag which represents hardware offloading support for network devices. Using the
loopback device for this purpose is usually fine, since it should always be
present. For rare cases in which the loopback device cannot be used to obtain the
appropriate feature flag, this option can be used to specify an alternative
interface for offload feature detection.
charon.plugins.kernel-netlink.ignore_retransmit_errors [no]
Whether to ignore errors potentially resulting from a retransmission.
charon.plugins.kernel-netlink.mss [0]
MSS to set on installed routes, 0 to disable.
charon.plugins.kernel-netlink.mtu [0]
MTU to set on installed routes, 0 to disable.
charon.plugins.kernel-netlink.parallel_route [no]
Whether to perform concurrent Netlink ROUTE queries on a single socket. While
parallel queries can improve throughput, it has more overhead. On vanilla Linux,
DUMP queries fail with EBUSY and must be retried, further decreasing performance.
charon.plugins.kernel-netlink.parallel_xfrm [no]
Whether to perform concurrent Netlink XFRM queries on a single socket.
charon.plugins.kernel-netlink.policy_update [no]
Whether to always use XFRM_MSG_UPDPOLICY to install policies.
charon.plugins.kernel-netlink.port_bypass [no]
Whether to use port or socket based IKE XFRM bypass policies. IKE bypass policies
are used to exempt IKE traffic from XFRM processing. The default socket based
policies are directly tied to the IKE UDP sockets, port based policies use global
XFRM bypass policies for the used IKE UDP ports.
charon.plugins.kernel-netlink.process_rules [no]
Whether to process changes in routing rules to trigger roam events. This is
currently only useful if the kernel based route lookup is used (i.e. if route
installation is disabled or an inverted fwmark match is configured).
charon.plugins.kernel-netlink.receive_buffer_size [0]
Maximum Netlink socket receive buffer in bytes. This value controls how many bytes
of Netlink messages can be received on a Netlink socket. The default value is set
by /proc/sys/net/core/rmem_default. The specified value cannot exceed the
system-wide maximum from /proc/sys/net/core/rmem_max, unless
force_receive_buffer_size is enabled.
charon.plugins.kernel-netlink.retries [0]
Number of Netlink message retransmissions to send on timeout.
charon.plugins.kernel-netlink.roam_events [yes]
Whether to trigger roam events when interfaces, addresses or routes change.
charon.plugins.kernel-netlink.set_proto_port_transport_sa [no]
Whether to set protocol and ports in the selector installed on transport mode IPsec
SAs in the kernel. While doing so enforces policies for inbound traffic, it also
prevents the use of a single IPsec SA by more than one traffic selector.
charon.plugins.kernel-netlink.spdh_thresh
XFRM policy hashing threshold configuration for IPv4 and IPv6.
The section defines hashing thresholds to configure in the kernel during daemon
startup. Each address family takes a threshold for the local subnet of an IPsec
policy (src in out-policies, dst in in- and forward-policies) and the remote subnet
(dst in out-policies, src in in- and forward-policies).
If the subnet has more or equal net bits than the threshold, the first threshold
bits are used to calculate a hash to lookup the policy.
Policy hashing thresholds are not supported before Linux 3.18 and might conflict
with socket policies before Linux 4.8.
charon.plugins.kernel-netlink.spdh_thresh.ipv4.lbits [32]
Local subnet XFRM policy hashing threshold for IPv4.
charon.plugins.kernel-netlink.spdh_thresh.ipv4.rbits [32]
Remote subnet XFRM policy hashing threshold for IPv4.
charon.plugins.kernel-netlink.spdh_thresh.ipv6.lbits [128]
Local subnet XFRM policy hashing threshold for IPv6.
charon.plugins.kernel-netlink.spdh_thresh.ipv6.rbits [128]
Remote subnet XFRM policy hashing threshold for IPv6.
charon.plugins.kernel-netlink.timeout [0]
Netlink message retransmission timeout, 0 to disable retransmissions.
charon.plugins.kernel-netlink.xfrm_acq_expires [165]
Lifetime of XFRM acquire state created by the kernel when traffic matches a trap
policy. The value gets written to /proc/sys/net/core/xfrm_acq_expires. Indirectly
controls the delay between XFRM acquire messages triggered by the kernel for a trap
policy. The same value is used as timeout for SPIs allocated by the kernel. The
default value equals the total retransmission timeout for IKE messages, see IKEv2
RETRANSMISSION in strongswan.conf(5).
charon.plugins.kernel-pfkey.events_buffer_size [0]
Size of the receive buffer for the event socket (0 for default size). Because
events are received asynchronously installing e.g. lots of policies may require a
larger buffer than the default on certain platforms in order to receive all
messages.
charon.plugins.kernel-pfkey.route_via_internal [no]
Whether to use the internal or external interface in installed routes. The internal
interface is the one where the IP address contained in the local traffic selector
is located, the external interface is the one over which the destination address of
the IPsec tunnel can be reached. This is not relevant if virtual IPs are used, for
which a TUN device is created that's used in the routes.
charon.plugins.kernel-pfroute.vip_wait [1000]
Time in ms to wait until virtual IP addresses appear/disappear before failing.
charon.plugins.led.activity_led []
charon.plugins.led.blink_time [50]
charon.plugins.load-tester
Section to configure the load-tester plugin, see LOAD TESTS in strongswan.conf(5)
for details.
charon.plugins.load-tester.addrs
Section that contains key/value pairs with address pools (in CIDR notation) to use
for a specific network interface e.g. eth0 = 10.10.0.0/16.
charon.plugins.load-tester.addrs_keep [no]
Whether to keep dynamic addresses even after the associated SA got terminated.
charon.plugins.load-tester.addrs_prefix [16]
Network prefix length to use when installing dynamic addresses. If set to -1 the
full address is used (i.e. 32 or 128).
charon.plugins.load-tester.ca_dir []
Directory to load (intermediate) CA certificates from.
charon.plugins.load-tester.child_rekey [600]
Seconds to start CHILD_SA rekeying after setup.
charon.plugins.load-tester.crl []
URI to a CRL to include as certificate distribution point in generated
certificates.
charon.plugins.load-tester.delay [0]
Delay between initiatons for each thread.
charon.plugins.load-tester.delete_after_established [no]
Delete an IKE_SA as soon as it has been established.
charon.plugins.load-tester.digest [sha1]
Digest algorithm used when issuing certificates.
charon.plugins.load-tester.dpd_delay [0]
DPD delay to use in load test.
charon.plugins.load-tester.dynamic_port [0]
Base port to be used for requests (each client uses a different port).
charon.plugins.load-tester.eap_password [default-pwd]
EAP secret to use in load test.
charon.plugins.load-tester.enable [no]
Enable the load testing plugin. WARNING: Never enable this plugin on productive
systems. It provides preconfigured credentials and allows an attacker to
authenticate as any user.
charon.plugins.load-tester.esp [aes128-sha1]
CHILD_SA proposal to use for load tests.
charon.plugins.load-tester.fake_kernel [no]
Fake the kernel interface to allow load-testing against self.
charon.plugins.load-tester.ike_rekey [0]
Seconds to start IKE_SA rekeying after setup.
charon.plugins.load-tester.init_limit [0]
Global limit of concurrently established SAs during load test.
charon.plugins.load-tester.initiator [0.0.0.0]
Address to initiate from.
charon.plugins.load-tester.initiator_auth [pubkey]
Authentication method(s) the intiator uses.
charon.plugins.load-tester.initiator_id []
Initiator ID used in load test.
charon.plugins.load-tester.initiator_match []
Initiator ID to match against as responder.
charon.plugins.load-tester.initiator_tsi []
Traffic selector on initiator side, as proposed by initiator.
charon.plugins.load-tester.initiator_tsr []
Traffic selector on responder side, as proposed by initiator.
charon.plugins.load-tester.initiators [0]
Number of concurrent initiator threads to use in load test.
charon.plugins.load-tester.issuer_cert []
Path to the issuer certificate (if not configured a hard-coded default value is
used).
charon.plugins.load-tester.issuer_key []
Path to private key that is used to issue certificates (if not configured a
hard-coded default value is used).
charon.plugins.load-tester.iterations [1]
Number of IKE_SAs to initiate by each initiator in load test.
charon.plugins.load-tester.mode [tunnel]
IPsec mode to use, one of tunnel, transport, or beet.
charon.plugins.load-tester.pool []
Provide INTERNAL_IPV4_ADDRs from a named pool.
charon.plugins.load-tester.preshared_key [<default-psk>]
Preshared key to use in load test.
charon.plugins.load-tester.proposal [aes128-sha1-modp768]
IKE proposal to use in load test.
charon.plugins.load-tester.request_virtual_ip [no]
Request an INTERNAL_IPV4_ADDR from the server.
charon.plugins.load-tester.responder [127.0.0.1]
Address to initiation connections to.
charon.plugins.load-tester.responder_auth [pubkey]
Authentication method(s) the responder uses.
charon.plugins.load-tester.responder_id []
Responder ID used in load test.
charon.plugins.load-tester.responder_tsi [initiator_tsi]
Traffic selector on initiator side, as narrowed by responder.
charon.plugins.load-tester.responder_tsr [initiator_tsr]
Traffic selector on responder side, as narrowed by responder.
charon.plugins.load-tester.shutdown_when_complete [no]
Shutdown the daemon after all IKE_SAs have been established.
charon.plugins.load-tester.socket [unix://${piddir}/charon.ldt]
Socket provided by the load-tester plugin.
charon.plugins.load-tester.version [0]
IKE version to use (0 means use IKEv2 as initiator and accept any version as
responder).
charon.plugins.lookip.socket [unix://${piddir}/charon.lkp]
Socket provided by the lookip plugin.
charon.plugins.ntru.parameter_set [optimum]
The following parameter sets are available: x9_98_speed, x9_98_bandwidth,
x9_98_balance and optimum, the last set not being part of the X9.98 standard but
having the best performance.
charon.plugins.openssl.engine_id [pkcs11]
ENGINE ID to use in the OpenSSL plugin.
charon.plugins.openssl.fips_mode [0]
Set OpenSSL FIPS mode: disabled(0), enabled(1), Suite B enabled(2).
charon.plugins.osx-attr.append [yes]
Whether DNS servers are appended to existing entries, instead of replacing them.
charon.plugins.p-cscf.enable
Section to enable requesting P-CSCF server addresses for individual connections.
charon.plugins.p-cscf.enable.<conn> [no]
<conn> is the name of a connection with an ePDG from which to request P-CSCF server
addresses. Requests will be sent for addresses of the same families for which
internal IPs are requested.
charon.plugins.pkcs11.modules
List of available PKCS#11 modules.
charon.plugins.pkcs11.modules.<name>.load_certs [yes]
Whether to automatically load certificates from tokens.
charon.plugins.pkcs11.modules.<name>.os_locking [no]
Whether OS locking should be enabled for this module.
charon.plugins.pkcs11.modules.<name>.path []
Full path to the shared object file of this PKCS#11 module.
charon.plugins.pkcs11.reload_certs [no]
Reload certificates from all tokens if charon receives a SIGHUP.
charon.plugins.pkcs11.use_dh [no]
Whether the PKCS#11 modules should be used for DH and ECDH (see use_ecc option).
charon.plugins.pkcs11.use_ecc [no]
Whether the PKCS#11 modules should be used for ECDH and ECDSA public key
operations. ECDSA private keys can be used regardless of this option.
charon.plugins.pkcs11.use_hasher [no]
Whether the PKCS#11 modules should be used to hash data.
charon.plugins.pkcs11.use_pubkey [no]
Whether the PKCS#11 modules should be used for public key operations, even for keys
not stored on tokens.
charon.plugins.pkcs11.use_rng [no]
Whether the PKCS#11 modules should be used as RNG.
charon.plugins.radattr.dir []
Directory where RADIUS attributes are stored in client-ID specific files.
charon.plugins.radattr.message_id [-1]
Attributes are added to all IKE_AUTH messages by default (-1), or only to the
IKE_AUTH message with the given IKEv2 message ID.
charon.plugins.random.random [${random_device}]
File to read random bytes from.
charon.plugins.random.strong_equals_true [no]
If set to yes the RNG_STRONG class reads random bytes from the same source as the
RNG_TRUE class.
charon.plugins.random.urandom [${urandom_device}]
File to read pseudo random bytes from.
charon.plugins.resolve.file [/etc/resolv.conf]
File where to add DNS server entries.
charon.plugins.resolve.resolvconf.iface_prefix [lo.inet.ipsec.]
Prefix used for interface names sent to resolvconf(8). The nameserver address is
appended to this prefix to make it unique. The result has to be a valid interface
name according to the rules defined by resolvconf. Also, it should have a high
priority according to the order defined in interface-order(5).
charon.plugins.revocation.enable_crl [yes]
Whether CRL validation should be enabled.
charon.plugins.revocation.enable_ocsp [yes]
Whether OCSP validation should be enabled.
charon.plugins.save-keys.esp [no]
Whether to save ESP keys.
charon.plugins.save-keys.ike [no]
Whether to save IKE keys.
charon.plugins.save-keys.load [no]
Whether to load the plugin.
charon.plugins.save-keys.wireshark_keys []
Directory where the keys are stored in the format supported by Wireshark. IKEv1
keys are stored in the ikev1_decryption_table file. IKEv2 keys are stored in the
ikev2_decryption_table file. Keys for ESP CHILD_SAs are stored in the esp_sa file.
charon.plugins.socket-default.fwmark []
Firewall mark to set on outbound packets.
charon.plugins.socket-default.set_source [yes]
Set source address on outbound packets, if possible.
charon.plugins.socket-default.set_sourceif [no]
Force sending interface on outbound packets, if possible. This allows using IPv6
link-local addresses as tunnel endpoints.
charon.plugins.socket-default.use_ipv4 [yes]
Listen on IPv4, if possible.
charon.plugins.socket-default.use_ipv6 [yes]
Listen on IPv6, if possible.
charon.plugins.sql.database []
Database URI for charon's SQL plugin. If it contains a password, make sure to
adjust the permissions of the config file accordingly.
charon.plugins.sql.loglevel [-1]
Loglevel for logging to SQL database.
charon.plugins.stroke.allow_swap [yes]
Analyze addresses/hostnames in left|right to detect which side is local and swap
configuration options if necessary. If disabled left is always local.
charon.plugins.stroke.ignore_missing_ca_basic_constraint [no]
Treat certificates in ipsec.d/cacerts and ipsec.conf ca sections as CA certificates
even if they don't contain a CA basic constraint.
charon.plugins.stroke.max_concurrent [4]
Maximum number of stroke messages handled concurrently.
charon.plugins.stroke.prevent_loglevel_changes [no]
If enabled log level changes via stroke socket are not allowed.
charon.plugins.stroke.secrets_file [${sysconfdir}/ipsec.secrets]
Location of the ipsec.secrets file
charon.plugins.stroke.socket [unix://${piddir}/charon.ctl]
Socket provided by the stroke plugin.
charon.plugins.stroke.timeout [0]
Timeout in ms for any stroke command. Use 0 to disable the timeout.
charon.plugins.systime-fix.interval [0]
Interval in seconds to check system time for validity. 0 disables the check.
charon.plugins.systime-fix.reauth [no]
Whether to use reauth or delete if an invalid cert lifetime is detected.
charon.plugins.systime-fix.threshold []
Threshold date where system time is considered valid. Disabled if not specified.
charon.plugins.systime-fix.threshold_format [%Y]
strptime(3) format used to parse threshold option.
charon.plugins.systime-fix.timeout [0s]
How long to wait for a valid system time if an interval is configured. 0 to recheck
indefinitely.
charon.plugins.tnc-ifmap.client_cert []
Path to X.509 certificate file of IF-MAP client.
charon.plugins.tnc-ifmap.client_key []
Path to private key file of IF-MAP client.
charon.plugins.tnc-ifmap.device_name []
Unique name of strongSwan server as a PEP and/or PDP device.
charon.plugins.tnc-ifmap.renew_session_interval [150]
Interval in seconds between periodic IF-MAP RenewSession requests.
charon.plugins.tnc-ifmap.server_cert []
Path to X.509 certificate file of IF-MAP server.
charon.plugins.tnc-ifmap.server_uri [https://localhost:8444/imap]
URI of the form [https://]servername[:port][/path].
charon.plugins.tnc-ifmap.username_password []
Credentials of IF-MAP client of the form username:password. If set, make sure to
adjust the permissions of the config file accordingly.
charon.plugins.tnc-imc.dlclose [yes]
Unload IMC after use.
charon.plugins.tnc-imc.preferred_language [en]
Preferred language for TNC recommendations.
charon.plugins.tnc-imv.dlclose [yes]
Unload IMV after use.
charon.plugins.tnc-imv.recommendation_policy [default]
TNC recommendation policy, one of default, any, or all.
charon.plugins.tnc-pdp.pt_tls.enable [yes]
Enable PT-TLS protocol on the strongSwan PDP.
charon.plugins.tnc-pdp.pt_tls.port [271]
PT-TLS server port the strongSwan PDP is listening on.
charon.plugins.tnc-pdp.radius.enable [yes]
Enable RADIUS protocol on the strongSwan PDP.
charon.plugins.tnc-pdp.radius.method [ttls]
EAP tunnel method to be used.
charon.plugins.tnc-pdp.radius.port [1812]
RADIUS server port the strongSwan PDP is listening on.
charon.plugins.tnc-pdp.radius.secret []
Shared RADIUS secret between strongSwan PDP and NAS. If set, make sure to adjust
the permissions of the config file accordingly.
charon.plugins.tnc-pdp.server []
Name of the strongSwan PDP as contained in the AAA certificate.
charon.plugins.tnc-pdp.timeout []
Timeout in seconds before closing incomplete connections.
charon.plugins.tnccs-11.max_message_size [45000]
Maximum size of a PA-TNC message (XML & Base64 encoding).
charon.plugins.tnccs-20.max_batch_size [65522]
Maximum size of a PB-TNC batch (upper limit via PT-EAP = 65529).
charon.plugins.tnccs-20.max_message_size [65490]
Maximum size of a PA-TNC message (upper limit via PT-EAP = 65497).
charon.plugins.tnccs-20.mutual [no]
Enable PB-TNC mutual protocol.
charon.plugins.tnccs-20.tests.pb_tnc_noskip [no]
Send an unsupported PB-TNC message type with the NOSKIP flag set.
charon.plugins.tnccs-20.tests.pb_tnc_version [2]
Send a PB-TNC batch with a modified PB-TNC version.
charon.plugins.tpm.fips_186_4 [no]
Is the TPM 2.0 FIPS-186-4 compliant, forcing e.g. the use of the default salt
length instead of maximum salt length with RSAPSS padding.
charon.plugins.tpm.tcti.name [device|tabrmd]
Name of TPM 2.0 TCTI library. Valid values: tabrmd, device or mssim. Defaults are
device if the /dev/tpmrm0 in-kernel TPM 2.0 resource manager device exists, and
tabrmd otherwise, requiring the d-bus based TPM 2.0 access broker and resource
manager to be available.
charon.plugins.tpm.tcti.opts [/dev/tpmrm0|<none>]
Options for the TPM 2.0 TCTI library. Defaults are /dev/tpmrm0 if the TCTI library
name is device and no options otherwise.
charon.plugins.tpm.use_rng [no]
Whether the TPM should be used as RNG.
charon.plugins.unbound.dlv_anchors []
File to read trusted keys for DLV (DNSSEC Lookaside Validation) from. It uses the
same format as trust_anchors. Only one DLV can be configured, which is then used
as a root trusted DLV, this means that it is a lookaside for the root.
charon.plugins.unbound.resolv_conf [/etc/resolv.conf]
File to read DNS resolver configuration from.
charon.plugins.unbound.trust_anchors [/etc/ipsec.d/dnssec.keys]
File to read DNSSEC trust anchors from (usually root zone KSK). The format of the
file is the standard DNS Zone file format, anchors can be stored as DS or DNSKEY
entries in the file.
charon.plugins.updown.dns_handler [no]
Whether the updown script should handle DNS servers assigned via IKEv1 Mode Config
or IKEv2 Config Payloads (if enabled they can't be handled by other plugins, like
resolve)
charon.plugins.vici.socket [unix://${piddir}/charon.vici]
Socket the vici plugin serves clients.
charon.plugins.whitelist.enable [yes]
Enable loaded whitelist plugin.
charon.plugins.whitelist.socket [unix://${piddir}/charon.wlst]
Socket provided by the whitelist plugin.
charon.plugins.wolfssl.fips_mode [no]
Enable to prevent loading the plugin if wolfSSL is not in FIPS mode.
charon.plugins.xauth-eap.backend [radius]
EAP plugin to be used as backend for XAuth credential verification.
charon.plugins.xauth-pam.pam_service [login]
PAM service to be used for authentication.
charon.plugins.xauth-pam.session [no]
Open/close a PAM session for each active IKE_SA.
charon.plugins.xauth-pam.trim_email [yes]
If an email address is received as an XAuth username, trim it to just the username
part.
charon.port [500]
UDP port used locally. If set to 0 a random port will be allocated.
charon.port_nat_t [4500]
UDP port used locally in case of NAT-T. If set to 0 a random port will be
allocated. Has to be different from charon.port, otherwise a random port will be
allocated.
charon.prefer_best_path [no]
By default, charon keeps SAs on the routing path with addresses it previously used
if that path is still usable. By setting this option to yes, it tries more
aggressively to update SAs with MOBIKE on routing priority changes using the
cheapest path. This adds more noise, but allows to dynamically adapt SAs to routing
priority changes. This option has no effect if MOBIKE is not supported or disabled.
charon.prefer_configured_proposals [yes]
Prefer locally configured proposals for IKE/IPsec over supplied ones as responder
(disabling this can avoid keying retries due to INVALID_KE_PAYLOAD notifies).
charon.prefer_temporary_addrs [no]
By default, permanent IPv6 source addresses are preferred over temporary ones (RFC
4941), to make connections more stable. Enable this option to reverse this.
It also affects which IPv6 addresses are announced as additional addresses if
MOBIKE is used. If the option is disabled, only permanent addresses are sent, and
only temporary ones if it is enabled.
charon.process_route [yes]
Process RTM_NEWROUTE and RTM_DELROUTE events.
charon.processor.priority_threads
Section to configure the number of reserved threads per priority class see JOB
PRIORITY MANAGEMENT in strongswan.conf(5).
charon.rdn_matching [strict]
How RDNs in subject DNs of certificates are matched against configured identities.
Possible values are strict (the default), reordered, and relaxed. With strict the
number, type and order of all RDNs has to match, wildcards (*) for the values of
RDNs are allowed (that's the case for all three variants). Using reordered also
matches DNs if the RDNs appear in a different order, the number and type still has
to match. Finally, relaxed also allows matches of DNs that contain more RDNs than
the configured identity (missing RDNs are treated like a wildcard match).
Note that reordered and relaxed impose a considerable overhead on memory usage and
runtime, in particular, for mismatches, compared to strict.
charon.receive_delay [0]
Delay in ms for receiving packets, to simulate larger RTT.
charon.receive_delay_request [yes]
Delay request messages.
charon.receive_delay_response [yes]
Delay response messages.
charon.receive_delay_type [0]
Specific IKEv2 message type to delay, 0 for any.
charon.replay_window [32]
Size of the AH/ESP replay window, in packets.
charon.retransmit_base [1.8]
Base to use for calculating exponential back off, see IKEv2 RETRANSMISSION in
strongswan.conf(5).
charon.retransmit_jitter [0]
Maximum jitter in percent to apply randomly to calculated retransmission timeout (0
to disable).
charon.retransmit_limit [0]
Upper limit in seconds for calculated retransmission timeout (0 to disable).
charon.retransmit_timeout [4.0]
Timeout in seconds before sending first retransmit.
charon.retransmit_tries [5]
Number of times to retransmit a packet before giving up.
charon.retry_initiate_interval [0]
Interval in seconds to use when retrying to initiate an IKE_SA (e.g. if DNS
resolution failed), 0 to disable retries.
charon.reuse_ikesa [yes]
Initiate CHILD_SA within existing IKE_SAs (always enabled for IKEv1).
charon.routing_table []
Numerical routing table to install routes to.
charon.routing_table_prio []
Priority of the routing table.
charon.rsa_pss [no]
Whether to use RSA with PSS padding instead of PKCS#1 padding by default.
charon.send_delay [0]
Delay in ms for sending packets, to simulate larger RTT.
charon.send_delay_request [yes]
Delay request messages.
charon.send_delay_response [yes]
Delay response messages.
charon.send_delay_type [0]
Specific IKEv2 message type to delay, 0 for any.
charon.send_vendor_id [no]
Send strongSwan vendor ID payload
charon.signature_authentication [yes]
Whether to enable Signature Authentication as per RFC 7427.
charon.signature_authentication_constraints [yes]
If enabled, signature schemes configured in rightauth, in addition to getting used
as constraints against signature schemes employed in the certificate chain, are
also used as constraints against the signature scheme used by peers during IKEv2.
charon.spi_label [0x0000000000000000]
Value mixed into the local IKE SPIs after applying spi_mask.
charon.spi_mask [0x0000000000000000]
Mask applied to local IKE SPIs before mixing in spi_label (bits set will be
replaced with spi_label).
charon.spi_max [0xcfffffff]
The upper limit for SPIs requested from the kernel for IPsec SAs.
charon.spi_min [0xc0000000]
The lower limit for SPIs requested from the kernel for IPsec SAs. Should not be set
lower than 0x00000100 (256), as SPIs between 1 and 255 are reserved by IANA.
charon.start-scripts
Section containing a list of scripts (name = path) that are executed when the
daemon is started.
charon.stop-scripts
Section containing a list of scripts (name = path) that are executed when the
daemon is terminated.
charon.syslog
Section to define syslog loggers, see LOGGER CONFIGURATION in strongswan.conf(5).
charon.syslog.<facility>
<facility> is one of the supported syslog facilities, see LOGGER CONFIGURATION in
strongswan.conf(5).
charon.syslog.<facility>.<subsystem> [<default>]
Loglevel for a specific subsystem.
charon.syslog.<facility>.default [1]
Specifies the default loglevel to be used for subsystems for which no specific
loglevel is defined.
charon.syslog.<facility>.ike_name [no]
Prefix each log entry with the connection name and a unique numerical identifier
for each IKE_SA.
charon.syslog.identifier []
Global identifier used for an openlog(3) call, prepended to each log message by
syslog. If not configured, openlog(3) is not called, so the value will depend on
system defaults (often the program name).
charon.threads [16]
Number of worker threads in charon. Several of these are reserved for long running
tasks in internal modules and plugins. Therefore, make sure you don't set this
value too low. The number of idle worker threads listed in ipsec statusall might be
used as indicator on the number of reserved threads.
charon.tls.cipher []
List of TLS encryption ciphers.
charon.tls.key_exchange []
List of TLS key exchange methods.
charon.tls.mac []
List of TLS MAC algorithms.
charon.tls.suites []
List of TLS cipher suites.
charon.tnc.tnc_config [/etc/tnc_config]
TNC IMC/IMV configuration file.
charon.user []
Name of the user the daemon changes to after startup.
charon.x509.enforce_critical [yes]
Discard certificates with unsupported or unknown critical extensions.
charon-nm.ca_dir [<default>]
Directory from which to load CA certificates if no certificate is configured.
charon-systemd.journal
Section to configure native systemd journal logger, very similar to the syslog
logger as described in LOGGER CONFIGURATION in strongswan.conf(5).
charon-systemd.journal.<subsystem> [<default>]
Loglevel for a specific subsystem.
charon-systemd.journal.default [1]
Specifies the default loglevel to be used for subsystems for which no specific
loglevel is defined.
imv_policy_manager.command_allow []
Shell command to be executed with recommendation allow.
imv_policy_manager.command_block []
Shell command to be executed with all other recommendations.
imv_policy_manager.database []
Database URI for the database that stores the package information. If it contains a
password, make sure to adjust the permissions of the config file accordingly.
imv_policy_manager.load [sqlite]
Plugins to load in IMV policy manager.
libimcv.debug_level [1]
Debug level for a stand-alone libimcv library.
libimcv.load [random nonce gmp pubkey x509]
Plugins to load in IMC/IMVs with stand-alone libimcv library.
libimcv.plugins.imc-attestation.aik_blob []
AIK encrypted private key blob file.
libimcv.plugins.imc-attestation.aik_cert []
AIK certificate file.
libimcv.plugins.imc-attestation.aik_handle []
AIK object handle.
libimcv.plugins.imc-attestation.aik_pubkey []
AIK public key file.
libimcv.plugins.imc-attestation.mandatory_dh_groups [yes]
Enforce mandatory Diffie-Hellman groups.
libimcv.plugins.imc-attestation.nonce_len [20]
DH nonce length.
libimcv.plugins.imc-attestation.pcr17_after []
PCR17 value after measurement.
libimcv.plugins.imc-attestation.pcr17_before []
PCR17 value before measurement.
libimcv.plugins.imc-attestation.pcr17_meas []
Dummy measurement value extended into PCR17 if the TBOOT log is not available.
libimcv.plugins.imc-attestation.pcr18_after []
PCR18 value after measurement.
libimcv.plugins.imc-attestation.pcr18_before []
PCR18 value before measurement.
libimcv.plugins.imc-attestation.pcr18_meas []
Dummy measurement value extended into PCR17 if the TBOOT log is not available.
libimcv.plugins.imc-attestation.pcr_info [no]
Whether to send pcr_before and pcr_after info.
libimcv.plugins.imc-attestation.use_quote2 [yes]
Use Quote2 AIK signature instead of Quote signature.
libimcv.plugins.imc-attestation.use_version_info [no]
Version Info is included in Quote2 signature.
libimcv.plugins.imc-hcd.push_info [yes]
Send quadruple info without being prompted.
libimcv.plugins.imc-hcd.subtypes []
Section to define PWG HCD PA subtypes.
libimcv.plugins.imc-hcd.subtypes.<section> []
Defines a PWG HCD PA subtype section. Recognized subtype section names are system,
control, marker, finisher, interface and scanner.
libimcv.plugins.imc-hcd.subtypes.<section>.<sw_type> []
Defines a software type section. Recognized software type section names are
firmware, resident_application and user_application.
libimcv.plugins.imc-hcd.subtypes.<section>.<sw_type>.<software> []
Defines a software section having an arbitrary name.
libimcv.plugins.imc-hcd.subtypes.<section>.<sw_type>.<software>.name []
Name of the software installed on the hardcopy device.
libimcv.plugins.imc-hcd.subtypes.<section>.<sw_type>.<software>.patches []
String describing all patches applied to the given software on this hardcopy
device. The individual patches are separated by a newline character '\n'.
libimcv.plugins.imc-hcd.subtypes.<section>.<sw_type>.<software>.string_version []
String describing the version of the given software on this hardcopy device.
libimcv.plugins.imc-hcd.subtypes.<section>.<sw_type>.<software>.version []
Hex-encoded version string with a length of 16 octets consisting of the fields
major version number (4 octets), minor version number (4 octets), build number (4
octets), service pack major number (2 octets) and service pack minor number (2
octets).
libimcv.plugins.imc-hcd.subtypes.<section>.attributes_natural_language [en]
Variable length natural language tag conforming to RFC 5646 specifies the language
to be used in the health assessment message of a given subtype.
libimcv.plugins.imc-hcd.subtypes.system.certification_state []
Hex-encoded certification state.
libimcv.plugins.imc-hcd.subtypes.system.configuration_state []
Hex-encoded configuration state.
libimcv.plugins.imc-hcd.subtypes.system.machine_type_model []
String specifying the machine type and model of the hardcopy device.
libimcv.plugins.imc-hcd.subtypes.system.pstn_fax_enabled [no]
Specifies if a PSTN facsimile interface is installed and enabled on the hardcopy
device.
libimcv.plugins.imc-hcd.subtypes.system.time_source []
String specifying the hostname of the network time server used by the hardcopy
device.
libimcv.plugins.imc-hcd.subtypes.system.user_application_enabled [no]
Specifies if users can dynamically download and execute applications on the
hardcopy device.
libimcv.plugins.imc-hcd.subtypes.system.user_application_persistence_enabled [no]
Specifies if user dynamically downloaded applications can persist outside the
boundaries of a single job on the hardcopy device.
libimcv.plugins.imc-hcd.subtypes.system.vendor_name []
String specifying the manufacturer of the hardcopy device.
libimcv.plugins.imc-hcd.subtypes.system.vendor_smi_code []
Integer specifying the globally unique 24-bit SMI code assigned to the manufacturer
of the hardcopy device.
libimcv.plugins.imc-os.device_cert []
Manually set the path to the client device certificate (e.g. /etc/pts/aikCert.der)
libimcv.plugins.imc-os.device_handle []
Manually set handle to a private key bound to a smartcard or TPM (e.g. 0x81010004)
libimcv.plugins.imc-os.device_id []
Manually set the client device ID in hexadecimal format (e.g.
1083f03988c9762703b1c1080c2e46f72b99cc31)
libimcv.plugins.imc-os.device_pubkey []
Manually set the path to the client device public key (e.g. /etc/pts/aikPub.der)
libimcv.plugins.imc-os.push_info [yes]
Send operating system info without being prompted.
libimcv.plugins.imc-scanner.push_info [yes]
Send open listening ports without being prompted.
libimcv.plugins.imc-swima.eid_epoch [0x11223344]
Set 32 bit epoch value for event IDs manually if software collector database is not
available.
libimcv.plugins.imc-swima.subscriptions [no]
Accept SW Inventory or SW Events subscriptions.
libimcv.plugins.imc-swima.swid_database []
URI to software collector database containing event timestamps, software creation
and deletion events and collected software identifiers. If it contains a password,
make sure to adjust the permissions of the config file accordingly.
libimcv.plugins.imc-swima.swid_directory [${prefix}/share]
Directory where SWID tags are located.
libimcv.plugins.imc-swima.swid_full [no]
Include file information in the XML-encoded SWID tags.
libimcv.plugins.imc-swima.swid_pretty [no]
Generate XML-encoded SWID tags with pretty indentation.
libimcv.plugins.imc-test.additional_ids [0]
Number of additional IMC IDs.
libimcv.plugins.imc-test.command [none]
Command to be sent to the Test IMV.
libimcv.plugins.imc-test.dummy_size [0]
Size of dummy attribute to be sent to the Test IMV (0 = disabled).
libimcv.plugins.imc-test.retry [no]
Do a handshake retry.
libimcv.plugins.imc-test.retry_command []
Command to be sent to the Test IMV in the handshake retry.
libimcv.plugins.imv-attestation.cadir []
Path to directory with AIK cacerts.
libimcv.plugins.imv-attestation.dh_group [ecp256]
Preferred Diffie-Hellman group.
libimcv.plugins.imv-attestation.hash_algorithm [sha256]
Preferred measurement hash algorithm.
libimcv.plugins.imv-attestation.mandatory_dh_groups [yes]
Enforce mandatory Diffie-Hellman groups.
libimcv.plugins.imv-attestation.min_nonce_len [0]
DH minimum nonce length.
libimcv.plugins.imv-os.remediation_uri []
URI pointing to operating system remediation instructions.
libimcv.plugins.imv-scanner.remediation_uri []
URI pointing to scanner remediation instructions.
libimcv.plugins.imv-swima.rest_api.timeout [120]
Timeout of SWID REST API HTTP POST transaction.
libimcv.plugins.imv-swima.rest_api.uri []
HTTP URI of the SWID REST API.
libimcv.plugins.imv-test.rounds [0]
Number of IMC-IMV retry rounds.
libimcv.stderr_quiet [no]
Disable output to stderr with a stand-alone libimcv library.
libimcv.swid_gen.command [/usr/local/bin/swid_generator]
SWID generator command to be executed.
libimcv.swid_gen.tag_creator.name [strongSwan Project]
Name of the tagCreator entity.
libimcv.swid_gen.tag_creator.regid [strongswan.org]
regid of the tagCreator entity.
manager.database []
Credential database URI for manager. If it contains a password, make sure to adjust
the permissions of the config file accordingly.
manager.debug [no]
Enable debugging in manager.
manager.load []
Plugins to load in manager.
manager.socket []
FastCGI socket of manager, to run it statically.
manager.threads [10]
Threads to use for request handling.
manager.timeout [15m]
Session timeout for manager.
medsrv.database []
Mediation server database URI. If it contains a password, make sure to adjust the
permissions of the config file accordingly.
medsrv.debug [no]
Debugging in mediation server web application.
medsrv.dpd [5m]
DPD timeout to use in mediation server plugin.
medsrv.load []
Plugins to load in mediation server plugin.
medsrv.password_length [6]
Minimum password length required for mediation server user accounts.
medsrv.rekey [20m]
Rekeying time on mediation connections in mediation server plugin.
medsrv.socket []
Run Mediation server web application statically on socket.
medsrv.threads [5]
Number of thread for mediation service web application.
medsrv.timeout [15m]
Session timeout for mediation service.
pki.load []
Plugins to load in ipsec pki tool.
pool.database []
Database URI for the database that stores IP pools and configuration attributes.
If it contains a password, make sure to adjust the permissions of the config
file accordingly.
pool.load []
Plugins to load in ipsec pool tool.
scepclient.load []
Plugins to load in ipsec scepclient tool.
sec-updater
Options for the sec-updater tool.
sec-updater.database []
Global IMV policy database URI. If it contains a password, make sure to adjust the
permissions of the config file accordingly.
sec-updater.load []
Plugins to load in sec-updater tool.
sec-updater.swid_gen.command [/usr/local/bin/swid_generator]
SWID generator command to be executed.
sec-updater.swid_gen.tag_creator.name [strongSwan Project]
Name of the tagCreator entity.
sec-updater.swid_gen.tag_creator.regid [strongswan.org]
regid of the tagCreator entity.
sec-updater.tmp.deb_file [/tmp/sec-updater.deb]
Temporary storage for downloaded deb package file.
sec-updater.tmp.tag_file [/tmp/sec-updater.tag]
Temporary storage for generated SWID tags.
sec-updater.tnc_manage_command [/var/www/tnc/manage.py]
strongTNC manage.py command used to import SWID tags.
starter.config_file [${sysconfdir}/ipsec.conf]
Location of the ipsec.conf file
starter.load_warning [yes]
Disable charon plugin load option warning.
sw-collector
Options for the sw-collector tool.
sw-collector.database []
URI to software collector database containing event timestamps, software creation
and deletion events and collected software identifiers. If it contains a password,
make sure to adjust the permissions of the config file accordingly.
sw-collector.first_file [/var/log/bootstrap.log]
Path pointing to file created when the Linux OS was installed.
sw-collector.first_time [0000-00-00T00:00:00Z]
Time in UTC when the Linux OS was installed.
sw-collector.history []
Path pointing to apt history.log file.
sw-collector.load []
Plugins to load in sw-collector tool.
sw-collector.rest_api.timeout [120]
Timeout of REST API HTTP POST transaction.
sw-collector.rest_api.uri []
HTTP URI of the central collector's REST API.
swanctl.load []
Plugins to load in swanctl.
swanctl.socket [unix://${piddir}/charon.vici]
VICI socket to connect to by default.
LOGGER CONFIGURATION
Options in strongswan.conf(5) provide a much more flexible way to configure loggers for
the IKE daemon charon than using the charondebug option in ipsec.conf(5).
Note: If any loggers are specified in strongswan.conf, charondebug does not have any
effect.
There are currently two types of loggers:
File loggers
Log directly to a file and are defined by specifying an arbitrarily named
subsection in the charon.filelog section. The full path to the file is configured
in the path setting of that subsection, however, if it only contains characters
permitted in section names, the setting may also be omitted and the path specified
as name of the subsection. To log to the console the two special filenames stdout
and stderr may be used.
Syslog loggers
Log into a syslog facility and are defined by specifying the facility to log to as
the name of a subsection in the charon.syslog section. The following facilities are
currently supported: daemon and auth.
Multiple loggers can be defined for each type with different log verbosity for the
different subsystems of the daemon.
Subsystems
dmn Main daemon setup/cleanup/signal handling
mgr IKE_SA manager, handling synchronization for IKE_SA access
ike IKE_SA
chd CHILD_SA
job Jobs queueing/processing and thread pool management
cfg Configuration management and plugins
knl IPsec/Networking kernel interface
net IKE network communication
asn Low-level encoding/decoding (ASN.1, X.509 etc.)
enc Packet encoding/decoding encryption/decryption operations
tls libtls library messages
esp libipsec library messages
lib libstrongwan library messages
tnc Trusted Network Connect
imc Integrity Measurement Collector
imv Integrity Measurement Verifier
pts Platform Trust Service
Loglevels
-1 Absolutely silent
0 Very basic auditing logs, (e.g. SA up/SA down)
1 Generic control flow with errors, a good default to see what's going on
2 More detailed debugging control flow
3 Including RAW data dumps in Hex
4 Also include sensitive material in dumps, e.g. keys
Example
charon {
filelog {
charon {
path = /var/log/charon.log
time_format = %b %e %T
append = no
default = 1
}
stderr {
ike = 2
knl = 3
ike_name = yes
}
}
syslog {
# enable logging to LOG_DAEMON, use defaults
daemon {
}
# minimalistic IKE auditing logging to LOG_AUTHPRIV
auth {
default = -1
ike = 0
}
}
}
JOB PRIORITY MANAGEMENT
Some operations in the IKEv2 daemon charon are currently implemented synchronously and
blocking. Two examples for such operations are communication with a RADIUS server via EAP-
RADIUS, or fetching CRL/OCSP information during certificate chain verification. Under high
load conditions, the thread pool may run out of available threads, and some more important
jobs, such as liveness checking, may not get executed in time.
To prevent thread starvation in such situations job priorities were introduced. The job
processor will reserve some threads for higher priority jobs, these threads are not
available for lower priority, locking jobs.
Implementation
Currently 4 priorities have been defined, and they are used in charon as follows:
CRITICAL
Priority for long-running dispatcher jobs.
HIGH INFORMATIONAL exchanges, as used by liveness checking (DPD).
MEDIUM Everything not HIGH/LOW, including IKE_SA_INIT processing.
LOW IKE_AUTH message processing. RADIUS and CRL fetching block here
Although IKE_SA_INIT processing is computationally expensive, it is explicitly assigned to
the MEDIUM class. This allows charon to do the DH exchange while other threads are blocked
in IKE_AUTH. To prevent the daemon from accepting more IKE_SA_INIT requests than it can
handle, use IKE_SA_INIT DROPPING.
The thread pool processes jobs strictly by priority, meaning it will consume all higher
priority jobs before looking for ones with lower priority. Further, it reserves threads
for certain priorities. A priority class having reserved n threads will always have n
threads available for this class (either currently processing a job, or waiting for one).
Configuration
To ensure that there are always enough threads available for higher priority tasks,
threads must be reserved for each priority class.
charon.processor.priority_threads.critical [0]
Threads reserved for CRITICAL priority class jobs
charon.processor.priority_threads.high [0]
Threads reserved for HIGH priority class jobs
charon.processor.priority_threads.medium [0]
Threads reserved for MEDIUM priority class jobs
charon.processor.priority_threads.low [0]
Threads reserved for LOW priority class jobs
Let's consider the following configuration:
charon {
processor {
priority_threads {
high = 1
medium = 4
}
}
}
With this configuration, one thread is reserved for HIGH priority tasks. As currently only
liveness checking and stroke message processing is done with high priority, one or two
threads should be sufficient.
The MEDIUM class mostly processes non-blocking jobs. Unless your setup is experiencing
many blocks in locks while accessing shared resources, threads for one or two times the
number of CPU cores is fine.
It is usually not required to reserve threads for CRITICAL jobs. Jobs in this class rarely
return and do not release their thread to the pool.
The remaining threads are available for LOW priority jobs. Reserving threads does not make
sense (until we have an even lower priority).
Monitoring
To see what the threads are actually doing, invoke ipsec statusall. Under high load,
something like this will show up:
worker threads: 2 or 32 idle, 5/1/2/22 working,
job queue: 0/0/1/149, scheduled: 198
From 32 worker threads,
2 are currently idle.
5 are running CRITICAL priority jobs (dispatching from sockets, etc.).
1 is currently handling a HIGH priority job. This is actually the thread currently
providing this information via stroke.
2 are handling MEDIUM priority jobs, likely IKE_SA_INIT or CREATE_CHILD_SA messages.
22 are handling LOW priority jobs, probably waiting for an EAP-RADIUS response while
processing IKE_AUTH messages.
The job queue load shows how many jobs are queued for each priority, ready for execution.
The single MEDIUM priority job will get executed immediately, as we have two spare threads
reserved for MEDIUM class jobs.
IKE_SA_INIT DROPPING
If a responder receives more connection requests per seconds than it can handle, it does
not make sense to accept more IKE_SA_INIT messages. And if they are queued but can't get
processed in time, an answer might be sent after the client has already given up and
restarted its connection setup. This additionally increases the load on the responder.
To limit the responder load resulting from new connection attempts, the daemon can drop
IKE_SA_INIT messages just after reception. There are two mechanisms to decide if this
should happen, configured with the following options:
charon.init_limit_half_open [0]
Limit based on the number of half open IKE_SAs. Half open IKE_SAs are SAs in
connecting state, but not yet established.
charon.init_limit_job_load [0]
Limit based on the number of jobs currently queued for processing (sum over all job
priorities).
The second limit includes load from other jobs, such as rekeying. Choosing a good value is
difficult and depends on the hardware and expected load.
The first limit is simpler to calculate, but includes the load from new connections only.
If your responder is capable of negotiating 100 tunnels/s, you might set this limit to
1000. The daemon will then drop new connection attempts if generating a response would
require more than 10 seconds. If you are allowing for a maximum response time of more than
30 seconds, consider adjusting the timeout for connecting IKE_SAs
(charon.half_open_timeout). A responder, by default, deletes an IKE_SA if the initiator
does not establish it within 30 seconds. Under high load, a higher value might be
required.
LOAD TESTS
To do stability testing and performance optimizations, the IKE daemon charon provides the
load-tester plugin. This plugin allows one to setup thousands of tunnels concurrently
against the daemon itself or a remote host.
WARNING: Never enable the load-testing plugin on productive systems. It provides
preconfigured credentials and allows an attacker to authenticate as any user.
Configuration details
For public key authentication, the responder uses the "CN=srv, OU=load-test, O=strongSwan"
identity. For the initiator, each connection attempt uses a different identity in the form
"CN=c1-r1, OU=load-test, O=strongSwan", where the first number indicates the client
number, the second the authentication round (if multiple authentication rounds are used).
For PSK authentication, FQDN identities are used. The server uses srv.strongswan.org, the
client uses an identity in the form c1-r1.strongswan.org.
For EAP authentication, the client uses a NAI in the form 100000000010001@strongswan.org.
To configure multiple authentication rounds, concatenate multiple methods using, e.g.
initiator_auth = pubkey|psk|eap-md5|eap-aka
The responder uses a hardcoded certificate based on a 1024-bit RSA key. This certificate
additionally serves as CA certificate. A peer uses the same private key, but generates
client certificates on demand signed by the CA certificate. Install the Responder/CA
certificate on the remote host to authenticate all clients.
To speed up testing, the load tester plugin implements a special Diffie-Hellman
implementation called modpnull. By setting
proposal = aes128-sha1-modpnull
this wicked fast DH implementation is used. It does not provide any security at all, but
allows one to run tests without DH calculation overhead.
Examples
In the simplest case, the daemon initiates IKE_SAs against itself using the loopback
interface. This will actually establish double the number of IKE_SAs, as the daemon is
initiator and responder for each IKE_SA at the same time. Installation of IPsec SAs would
fail, as each SA gets installed twice. To simulate the correct behavior, a fake kernel
interface can be enabled which does not install the IPsec SAs at the kernel level.
A simple loopback configuration might look like this:
charon {
# create new IKE_SAs for each CHILD_SA to simulate
# different clients
reuse_ikesa = no
# turn off denial of service protection
dos_protection = no
plugins {
load-tester {
# enable the plugin
enable = yes
# use 4 threads to initiate connections
# simultaneously
initiators = 4
# each thread initiates 1000 connections
iterations = 1000
# delay each initiation in each thread by 20ms
delay = 20
# enable the fake kernel interface to
# avoid SA conflicts
fake_kernel = yes
}
}
}
This will initiate 4000 IKE_SAs within 20 seconds. You may increase the delay value if
your box can not handle that much load, or decrease it to put more load on it. If the
daemon starts retransmitting messages your box probably can not handle all connection
attempts.
The plugin also allows one to test against a remote host. This might help to test against
a real world configuration. A connection setup to do stress testing of a gateway might
look like this:
charon {
reuse_ikesa = no
threads = 32
plugins {
load-tester {
enable = yes
# 10000 connections, ten in parallel
initiators = 10
iterations = 1000
# use a delay of 100ms, overall time is:
# iterations * delay = 100s
delay = 100
# address of the gateway
remote = 1.2.3.4
# IKE-proposal to use
proposal = aes128-sha1-modp1024
# use faster PSK authentication instead
# of 1024bit RSA
initiator_auth = psk
responder_auth = psk
# request a virtual IP using configuration
# payloads
request_virtual_ip = yes
# enable CHILD_SA every 60s
child_rekey = 60
}
}
}
IKEv2 RETRANSMISSION
Retransmission timeouts in the IKEv2 daemon charon can be configured globally using the
three keys listed below:
charon.retransmit_base [1.8]
charon.retransmit_timeout [4.0]
charon.retransmit_tries [5]
charon.retransmit_jitter [0]
charon.retransmit_limit [0]
The following algorithm is used to calculate the timeout:
relative timeout = retransmit_timeout * retransmit_base ^ (n-1)
Where n is the current retransmission count. The calculated timeout can't exceed the
configured retransmit_limit (if any), which is useful if the number of retries is high.
If a jitter in percent is configured, the timeout is modified as follows:
relative timeout -= random(0, retransmit_jitter * relative timeout)
Using the default values, packets are retransmitted in:
Retransmission Relative Timeout Absolute Timeout
─────────────────────────────────────────────────────
1 4s 4s
2 7s 11s
3 13s 24s
4 23s 47s
5 42s 89s
giving up 76s 165s
VARIABLES
The variables used above are configured as follows:
${piddir} /var/run
${prefix} /usr
${random_device} /dev/random
${urandom_device} /dev/urandom
FILES
/etc/strongswan.conf configuration file
/etc/strongswan.d/ directory containing included config snippets
/etc/strongswan.d/charon/ plugin specific config snippets
SEE ALSO
ipsec.conf(5), ipsec.secrets(5), ipsec(8), charon-cmd(8)
HISTORY
Written for the strongSwan project ⟨http://www.strongswan.org⟩ by Tobias Brunner, Andreas
Steffen and Martin Willi.