Ubuntu Manpage: dhcp6c.conf — DHCPv6 client configuration file

Provided by: wide-dhcpv6-client_20080615-12_amd64

NAME

     dhcp6c.conf — DHCPv6 client configuration file

SYNOPSIS

     /etc/wide-dhcpv6/dhcp6c.conf

DESCRIPTION

     The dhcp6c.conf file contains configuration information for KAME's DHCPv6 client, dhcp6c.  The
     configuration file consists of a sequence of statements terminated by a semi-colon (`;').  Statements are
     composed of tokens separated by white space, which can be any combination of blanks, tabs and newlines.  In
     some cases a set of statements is combined with a pair of brackets, which is regarded as a single token.
     Lines beginning with ‘#’ are comments.

Interface specification

     There are some statements that may or have to specify interface.  Interfaces are specified in the form of
     "name unit", such as fxp0 and gif1.

DHCPv6 options

Some configuration statements take the description of a DHCPv6 option as an argument. The followings are
the format and description of available DHCPv6 options.
domain-name-servers
means a Domain Name Server option.
domain-name
means a domain name option.
ntp-servers
means an NTP server option. As of this writing, the option type for this option is not officially
assigned. dhcp6c will reject this option unless it is explicitly built to accept the option.
sip-server-address
means a SIP Server address option.
sip-server-domain-name
means a SIP server domain name option.
nis-server-address
means a NIS Server address option.
nis-domain-name
means a NIS domain name option.
nisp-server-address
means a NIS+ Server address option.
nisp-domain-name
means a NIS+ domain name option.
bcmcs-server-address
means a BCMCS Server address option.
bcmcs-server-domain-name
means a BCMCS server domain name option.
ia-pd ID
means an IA_PD (Identity Association for Prefix Delegation) option. ID is a decimal number of the
IAID (see below about identity associations).
ia-na ID
means an IA_PD (Identity Association for Non-temporary Addresses) option. ID is a decimal number
of the IAID (see below about identity associations).
rapid-commit
means a rapid-commit option.
authentication authname
means an authentication option. authname is a string specifying parameters of the authentication
protocol. An authentication statement for authname must be provided.

Interface statement

An interface statement specifies configuration parameters on the interface. The generic format of an
interface statement is as follows:
interface interface { substatements };
The followings are possible substatements in an interface statement.
send send-options ;
This statement specifies DHCPv6 options to be sent to the server(s). Some options can only
appear in particular messages according to the specification, in which case the appearance
of the options is limited to be compliant with the specification.

send-options is a comma-separated list of options, each of which should be specified as
described above. Multiple send statements can also be specified, in which case all the
specified options will be sent.

When rapid-commit is specified, dhcp6c will include a rapid-commit option in solicit
messages and wait for an immediate reply instead of advertisements.

When ia-pd is specified, dhcp6c will initiate prefix delegation as a requesting router by
including an IA_PD option with the specified ID in solicit messages.

When ia-na is specified, dhcp6c will initiate stateful address assignment by including an
IA_NA option with the specified ID in solicit messages.

In either case, a corresponding identity association statement must exist with the same ID.
request request-options;
This statement specifies DHCPv6 options to be included in an option-request option.
request-options is a comma-separated list of options, which can consist of the following
options.
domain-name-servers
requests a list of Domain Name Server addresses.
domain-name
requests a DNS search path.
ntp-servers
requests a list of NTP server addresses. As of this writing, the option type for
this option is not officially assigned. dhcp6c will reject this option unless it
is explicitly built to accept the option.
sip-server-address
requests a list of SIP server addresses.
sip-domain-name
requests a SIP server domain name.
nis-server-address
requests a list of NIS server addresses.
nis-domain-name
requests a NIS domain name.
nisp-server-address
requests a list of NIS+ server addresses.
nisp-domain-name
requests a NIS+ domain name.
bcmcs-server-address
requests a list of BCMCS server addresses.
bcmcs-domain-name
requests a BCMCS domain name.
refreshtime
means an information refresh time option. This can only be specified when sent
with information-request messages; dhcp6c will ignore this option for other
messages.
Multiple request statements can also be specified, in which case all the specified options
will be requested.
information-only;
This statement specifies dhcp6c to only exchange informational configuration parameters
with servers. A list of DNS server addresses is an example of such parameters. This
statement is useful when the client does not need stateful configuration parameters such as
IPv6 addresses or prefixes.
script "script-name";
This statement specifies a path to script invoked by dhcp6c on a certain condition
including when the daemon receives a reply message. script-name must be the absolute path
from root to the script file, be a regular file, and be created by the same owner who runs
the daemon.

Profile statement

     Some setups may require to configure an interface independently from its name.  Profiles are available for
     this particular purpose.  They follow the same syntax as an interface statement except they can be
     arbitrarily named.  It is then possible to choose which profile to use for a given interface on the command
     line.

Identity association statement

Identity association (IA) is a key notion of DHCPv6. An IA is uniquely identified in a client by a pair of
IA type and IA identifier (IAID). An IA is associated with configuration information dependent on the IA
type.

An identity association statement defines a single IA with some client-side configuration parameters. Its
format is as follows:
id-assoc type [ID] { substatements };
type is a string for the type of this IA. The current implementation supports ‘na’ (non-temporary
address allocation) ‘pd’ (prefix delegation) for the IA type. ID is a decimal number of IAID. If
omitted, the value 0 will be used by default. substatements is a sequence of statements that
specifies configuration parameters for this IA. Each statement may or may not be specific to the
type of IA.

The followings are possible substatements for an IA of type na.
address ipv6-address pltime [vltime];
specifies an address and related parameters that the client wants to be allocated.
Multiple addresses can be specified, each of which is described as a separate address
substatement. dhcp6c will include all the addresses (and related parameters) in Solicit
messages, as an IA_NA prefix option encapsulated in the corresponding IA_NA option. Note,
however, that the server may or may not respect the specified prefix parameters. For
parameters of the address substatement, see dhcp6s.conf(5).

The followings are possible substatements for an IA of type pd.
prefix_interface_statement
specifies the client's local configuration of how delegated prefixes should be used (see
below).
prefix ipv6-prefix pltime [vltime];
specifies a prefix and related parameters that the client wants to be delegated. Multiple
prefixes can be specified, each of which is described as a separate prefix substatement.
dhcp6c will include all the prefixes (and related parameters) in Solicit messages, as an
IA_PD prefix option encapsulated in the corresponding IA_PD option. Note, however, that
the server may or may not respect the specified prefix parameters. For parameters of the
prefix substatement, see dhcp6s.conf(5).

Prefix interface statement

A prefix interface statement specifies configuration parameters of prefixes on local interfaces that are
derived from delegated prefixes. A prefix interface statement can only appear as a substatement of an
identity association statement with the type pd. The generic format of an interface statement is as
follows:
prefix-interface interface { substatements };
When an IPv6 prefix is delegated from a DHCPv6 server, dhcp6c will assign a prefix on the interface
unless the interface receives the DHCPv6 message that contains the prefix with the delegated prefix
and the parameters provided in substatements. Possible substatements are as follows:
sla-id ID ;
This statement specifies the identifier value of the site-level aggregator (SLA) on the
interface. ID must be a decimal integer which fits in the length of SLA IDs (see below).
For example, if ID is 1 and the client is delegated an IPv6 prefix 2001:db8:ffff::/48,
dhcp6c will combine the two values into a single IPv6 prefix, 2001:db8:ffff:1::/64, and
will configure the prefix on the specified interface.
sla-len length ;
This statement specifies the length of the SLA ID in bits. length must be a decimal number
between 0 and 128. If the length is not specified by this statement, the default value 16
will be used.
ifid ID ;
This statement specifies the interface id. ID must be a decimal integer. It will be
combined with the delegated prefix and the sla-id to form a complete interface address.
The default is to use the EUI-64 address of the interface.

Authentication statement

An authentication statement defines a set of authentication parameters used in DHCPv6 exchanges with the
server(s). The format of an authentication statement is as follows:
authentication authname { substatements };
authname is a string which is unique among all authentication statements in the configuration file.
It will specify a particular set of authentication parameters when authentication option is
specified in the interface statement. Possible substatements of the authentication statement are
as follows:
protocol authprotocol ;
specifies the authentication protocol. Currently, the only available protocol as
authprotocol is delayed, which means the DHCPv6 delayed authentication protocol.
algorithm authalgorithm ;
specifies the algorithm for this authentication. Currently, the only available algorithm
is HMAC-MD5, which can be specified as one of the followings: hmac-md5, HMAC-MD5, hmacmd5,
or HMACMD5. This substatement can be omitted. In this case, HMAC-MD5 will be used as the
algorithm.
rdm replay-detection-method ;
specifies the replay protection method for this authentication. Currently, the only
available method is monocounter, which means the use of a monotonically increasing counter.
If this method is specified, dhcp6c will use an NTP-format timestamp when it authenticates
the message. This substatement can be omitted, in which case monocounter will be used as
the method.

Keyinfo statement

A keyinfo statement defines a secret key shared with the server(s) to authenticate DHCPv6 messages. The
format of a keyinfo statement is as follows:
keyinfo keyname { substatements };
keyname is an arbitrary string. It does not affect client's behavior but is provided for
readability of log messages. Possible substatements of the keyinfo statement are as follows:
realm "realmname" ;
specifies the DHCP realm. realmname is an arbitrary string, but is typically expected to
be a domain name like "kame.net" .
keyid ID ;
specifies the key identifier, ID, as a decimal number. A secret key is uniquely identified
within the client by the DHCP realm and the key identifier.
secret "secret-value" ;
specifies the shared secret of this key. "secret-value" is a base-64 encoded string of the
secret.
expire "expiration-time" ;
specifies the expiration time of this key. "expiration-time" should be formatted in one of
the followings: yyyy-mm-dd HH:MM, mm-dd HH:MM, or HH:MM, where yyyy is the year with
century (e.g., 2004), mm is the month, dd is the day of the month, HH is the hour of
24-hour clock, and MM is the minute, each of which is given as a decimal number.
Additionally, a special keyword forever can be specified as expiration-time, which means
the key has an infinite lifetime and never expires. This substatement can be omitted, in
which case forever will be used by default.

Examples

     The followings are a sample configuration to be delegated an IPv6 prefix from an upstream service provider.
     With this configuration dhcp6c will send solicit messages containing an IA_PD option, with an IAID 0, on to
     an upstream PPP link, ppp0.  After receiving some prefixes from a server, dhcp6c will then configure
     derived IPv6 prefixes with the SLA ID 1 on a local ethernet interface, ne0.  Note that the IAID for the
     id-assoc statement is 0 according to the default.

     interface ppp0 {
             send ia-pd 0;
     };

     id-assoc pd {
             prefix-interface ne0 {
                     sla-id 1;
             };
     };

     If a shared secret should be configured in both the client and the server for DHCPv6 authentication, it
     would be specified in the configuration file as follows:

     keyinfo kame-key {
             realm "kame.net";
             keyid 1;
             secret "5pvW2g48OHPvkYMJSw0vZA==";
     };

     One easy way of generating a new secret in the base64 format is to execute the openssl(1) command (when
     available) as follows,

     % openssl rand -base64 16

     and copy the output to the dhcp6c.conf file.

     To include an authentication option for DHCPv6 authentication, the interface statement should be modified
     and an authentication statement should be added as follows:

     interface ppp0 {
             send ia-pd 0;
             send authentication kame;
     };

     authentication kame {
             protocol delayed;
     };

     interface fxp0 {
             send ia-na 0;
     };

HISTORY

     The dhcp6c.conf configuration file first appeared in the WIDE/KAME IPv6 protocol stack kit.