Provided by: strongswan-ikev1_4.5.2-1.1ubuntu1_i386 bug


       pluto - IPsec IKE keying daemon and control interface

       whack - control interface for IKE keying daemon


       ipsec pluto [--help] [--version] [--optionsfrom filename] [--nofork]
              [--stderrlog] [--uniqueids] [--interface interfacename]
              [--ikeport portnumber] [--ctlbase path] [--secretsfile secrets
              file] [--adns pathname] [--lwdnsq pathname] [--perpeerlog]
              [--perpeerlogbase dirname] [--debugnone] [--debugall]
              [--debugraw] [--debugcrypt] [--debugparsing] [--debugemitting] [--debugcontrol] [--debuglifecycle] [--debugkernel]
              [--debugdns] [--debugoppo] [--debugprivate]

       ipsec whack [--help] [--version]

       ipsec whack --name connection-name
              [--id id] [--host ipaddress] [--ikeport portnumber]
              [--nexthop ipaddress] [--client subnet] [--dnskeyondemand]
              [--updown updown]
              [--id id] [--host ipaddress] [--ikeport portnumber]
              [--nexthop ipaddress] [--client subnet] [--dnskeyondemand]
              [--updown updown]
              [--psk] [--rsasig] [--encrypt] [--authenticate] [--compress]
              [--tunnel] [--pfs] [--disablearrivalcheck] [--ipv4] [--ipv6]
              [--tunnelipv4] [--tunnelipv6] [--ikelifetime seconds]
              [--ipseclifetime seconds] [--rekeymargin seconds]
              [--rekeyfuzz percentage] [--keyingtries count] [--dontrekey]
              [--delete] [--ctlbase path] [--optionsfrom filename]
              [--label string]

       ipsec whack --keyid id [--addkey] [--pubkeyrsa key] [--ctlbase path]
              [--optionsfrom filename] [--label string]

       ipsec whack --myid id

       ipsec whack --listen|--unlisten [--ctlbase path]
              [--optionsfrom filename] [--label string]

       ipsec whack --route|--unroute --name connection-name [--ctlbase path]
              [--optionsfrom filename] [--label string]

       ipsec whack --initiate|--terminate --name connection-name
              [--asynchronous] [--ctlbase path] [--optionsfrom filename]
              [--label string]

       ipsec whack [--tunnelipv4] [--tunnelipv6] --oppohere ipaddress
              --oppothere ipaddress

       ipsec whack --delete --name connection-name [--ctlbase path]
              [--optionsfrom filename] [--label string]

       ipsec whack --deletestate state-number [--ctlbase path]
              [--optionsfrom filename] [--label string]

       ipsec whack [--name connection-name] [--debugnone] [--debugall]
              [--debugraw] [--debugcrypt] [--debugparsing] [--debugemitting] [--debugcontrol] [--debuglifecycle] [--debugkernel]
              [--debugdns] [--debugoppo] [--debugprivate] [--ctlbase path]
              [--optionsfrom filename] [--label string]

       ipsec whack --status [--ctlbase path] [--optionsfrom filename]
              [--label string]

       ipsec whack --shutdown [--ctlbase path] [--optionsfrom filename]
              [--label string]


       pluto is an IKE (``IPsec Key Exchange'') daemon.  whack is an auxiliary
       program to allow requests to be made to a running pluto.

       pluto  is  used to automatically build shared ``security associations''
       on a system that has IPsec, the secure IP protocol.   In  other  words,
       pluto  can  eliminate  much  of  the work of manual keying.  The actual
       secure transmission of packets  is  the  responsibility  of  the  Linux
       kernel.   ipsec_auto(8)  provides  a more convenient interface to pluto
       and whack.

   IKE's Job
       A Security Association (SA) is an agreement between two  network  nodes
       on  how  to  process  certain  traffic  between  them.  This processing
       involves encapsulation, authentication, encryption, or compression.

       IKE  can  be  deployed  on  a  network  node  to   negotiate   Security
       Associations  for  that  node.   These  IKE  implementations  can  only
       negotiate with other IKE implementations, so IKE must be on  each  node
       that  is  to  be an endpoint of an IKE-negotiated Security Association.
       No other nodes need to be running IKE.

       An IKE instance (i.e. an IKE implementation  on  a  particular  network
       node)  communicates  with another IKE instance using UDP IP packets, so
       there must be a route between the nodes in each direction.

       The negotiation of Security Associations requires a number  of  choices
       that  involve  tradeoffs  between  security,  convenience,  trust,  and
       efficiency.  These are policy issues and are normally specified to  the
       IKE instance by the system administrator.

       IKE deals with two kinds of Security Associations.  The first part of a
       negotiation between IKE instances is to build an ISAKMP SA.  An  ISAKMP
       SA  is  used  to protect communication between the two IKEs.  IPsec SAs
       can then be built by the IKEs - these are used to  carry  protected  IP
       traffic between the systems.

       The negotiation of the ISAKMP SA is known as Phase 1.  In theory, Phase
       1 can be accomplished by a couple of different exchange types,  but  we
       only  implement  one  called  Main  Mode (we don't implement Aggressive

       Any negotiation under the protection of an  ISAKMP  SA,  including  the
       negotiation  of  IPsec SAs, is part of Phase 2.  The exchange type that
       we use to negotiate an IPsec SA is called Quick Mode.

       IKE instances must be able to authenticate each other as part of  their
       negotiation  of  an  ISAKMP SA.  This can be done by several mechanisms
       described in the draft standards.

       IKE negotiation can be initiated by any instance with  any  other.   If
       both  can  find  an  agreeable  set  of  characteristics for a Security
       Association, and both recognize each others authenticity, they can  set
       up a Security Association.  The standards do not specify what causes an
       IKE instance to initiate a negotiation.

       In summary, an IKE instance is prepared to automate the  management  of
       Security  Associations  in an IPsec environment, but a number of issues
       are considered policy and are left in the system administrator's hands.

       pluto is an implementation of IKE.  It runs as a daemon  on  a  network
       node.   Currently, this network node must be a Linux 2.6 system running
       the native NETKEY IPsec stack.

       pluto only implements a subset of  IKE.   This  is  enough  for  it  to
       interoperate  with  other  instances  of  pluto,  and  many  other  IKE
       implementations.  We are working on implementing more of IKE.

       The policy for acceptable characteristics for Security Associations  is
       mostly hardwired into the code of pluto (spdb.c).  Eventually this will
       be moved into a security policy  database  with  reasonable  expressive
       power and more convenience.

       pluto  uses shared secrets or RSA signatures to authenticate peers with
       whom it is negotiating.

       pluto initiates negotiation  of  a  Security  Association  when  it  is
       manually  prodded:  the  program whack is run to trigger this.  It will
       also initiate a negotiation when the Linux  kernel  traps  an  outbound
       packet for Opportunistic Encryption.

       pluto  implements  ISAKMP  SAs  itself.   After  it  has negotiated the
       characteristics of  an  IPsec  SA,  it  directs  the  Linux  kernel  to
       implement  it.   It  also  invokes  a script to adjust any firewall and
       issue route(8) commands.

       When pluto shuts down, it closes all Security Associations.

   Before Running Pluto
       pluto runs as a daemon with userid root.   Before  running  it,  a  few
       things must be set up.

       pluto requires a Linux 2.6 kernel with the modules for the native IPsec
       stack enabled.

       pluto supports multiple public networks (that  is,  networks  that  are
       considered  insecure  and  thus need to have their traffic encrypted or
       authenticated).  It discovers the public interfaces to use  by  looking
       at  all  interfaces  that are configured (the --interface option can be
       used to limit the interfaces considered).  It does this only when whack
       tells  it  to  --listen,  so the interfaces must be configured by then.
       ifconfig(8) with the -a flag will show the  name  and  status  of  each
       network interface.

       pluto  requires  a  database of preshared secrets and RSA private keys.
       This is described in the ipsec.secrets(5).  pluto is told of RSA public
       keys  via  whack  commands.  If the connection is Opportunistic, and no
       RSA public key is known, pluto will attempt to fetch RSA keys using the
       Domain Name System.

   ipsec.secrets file
       A pluto daemon and another IKE daemon (for example, another instance of
       pluto) must convince each other that they are who they are supposed  to
       be   before  any  negotiation  can  succeed.   This  authentication  is
       accomplished by using either secrets that have been  shared  beforehand
       (manually) or by using RSA signatures.  There are other techniques, but
       they have not been implemented in pluto.

       The file /etc/ipsec.secrets is used to keep preshared secret  keys  and
       RSA  private  keys  for  authentication  with  other  IKE daemons.  For
       debugging, there is an argument to the pluto command to use a different
       file.  This file is described in ipsec.secrets(5).

   Running Pluto
       To  fire  up  the daemon, just type pluto (be sure to be running as the
       superuser).  The default IKE port number is 500, the UDP port  assigned
       by IANA for IKE Daemons.  pluto must be run by the superuser to be able
       to use the UDP 500 port.

       pluto attempts to create a lockfile with the  name  /var/run/
       If the lockfile cannot be created, pluto exits - this prevents multiple
       plutos from competing  Any ``leftover'' lockfile must be removed before
       pluto  will  run.   pluto writes its pid into this file so that scripts
       can find it.  This lock will not function properly if it is on  an  NFS
       volume  (but  sharing  locks  on  multiple  machines doesn't make sense

       pluto then forks and  the  parent  exits.   This  is  the  conventional
       ``daemon  fork''.  It can make debugging awkward, so there is an option
       to suppress this fork.

       All  logging,  including  diagnostics,  is  sent  to   syslog(3)   with
       facility=authpriv;  it decides where to put these messages (possibly in
       /var/log/secure).  Since this too can make debugging awkward, there  is
       an option to steer logging to stderr.

       If  the  --perpeerlog  option is given, then pluto will open a log file
       per connection. By  default,  this  is  in  /var/log/pluto/peer,  in  a
       subdirectory  formed  by turning all dot (.) [IPv4} or colon (:) [IPv6]
       into slashes (/).

       The base directory can be changed with the --perpeerlogbase.

       Once pluto is started, it waits for requests from whack.

   Pluto's Internal State
       To understand how to use pluto, it is helpful to  understand  a  little
       about  its  internal  state.  Furthermore, the terminology is needed to
       decipher some of the diagnostic messages.

       The  (potential)  connection  database  describes   attributes   of   a
       connection.   These  include  the  IP addresses of the hosts and client
       subnets and the security characteristics desired.  pluto requires  this
       information  (simply  called  a  connection) before it can respond to a
       request to build an SA.  Each connection is given a  name  when  it  is
       created, and all references are made using this name.

       During  the  IKE  exchange  to  build  an SA, the information about the
       negotiation is represented  in  a  state  object.   Each  state  object
       reflects  how far the negotiation has reached.  Once the negotiation is
       complete and the SA established, the state object remains to  represent
       the  SA.   When  the  SA  is terminated, the state object is discarded.
       Each State object is given a serial number and this is used to refer to
       the state objects in logged messages.

       Each  state object corresponds to a connection and can be thought of as
       an instantiation of that connection.  At any particular time, there may
       be   any   number  of  state  objects  corresponding  to  a  particular
       connection.  Often there is one representing an ISAKMP SA  and  another
       representing an IPsec SA.

       Each  connection  may  be routed, and must be while it has an IPsec SA.
       The  connection  specifies  the  characteristics  of  the  route:   the
       interface  on  this  machine,  the  ``gateway''  (the nexthop), and the
       peer's client subnet.  Two connections may not be simultaneously routed
       if  they  are  for  the  same  peer's  client  subnet but use different
       interfaces or gateways (pluto's logic does  not  reflect  any  advanced
       routing capabilities).

       Each eroute is associated with the state object for an IPsec SA because
       it has the particular characteristics of the SA.  Two eroutes  conflict
       if  they  specify  the  identical  local and remote clients (unlike for
       routes, the local clients are taken into account).

       When pluto needs to install a route for a connection, it must make sure
       that  no  conflicting  route  is  in  use.  If another connection has a
       conflicting route, that route will be taken down, as long as  there  is
       no  IPsec  SA instantiating that connection.  If there is such an IPsec
       SA, the attempt to install a route will fail.

       There is an exception.  If pluto, as  Responder,  needs  to  install  a
       route to a fixed client subnet for a connection, and there is already a
       conflicting route, then the SAs using the route  are  deleted  to  make
       room  for  the  new  SAs.   The rationale is that the new connection is
       probably more current.  The need for this usually is a product of  Road
       Warrior  connections (these are explained later; they cannot be used to

       When pluto needs to install an eroute for an  IPsec  SA  (for  a  state
       object),  first  the  state object's connection must be routed (if this
       cannot be done, the eroute  and  SA  will  not  be  installed).   If  a
       conflicting  eroute  is  already  in  place for another connection, the
       eroute and SA  will  not  be  installed  (but  note  that  the  routing
       exception   mentioned   above  may  have  already  deleted  potentially
       conflicting SAs).  If another IPsec SA for the same connection  already
       has  an  eroute,  all  its  outgoing  traffic  is taken over by the new
       eroute.   The  incoming  traffic  will  still   be   processed.    This
       characteristic is exploited during rekeying.

       Some  of  these  routing  characteristics  are  specific  to KLIPS, the
       FreeS/WAN implementation of IPsec and are  not  relevant  when  running
       pluto on the native Linux 2.6 IPsec stack.

   Using Whack
       whack  is  used  to  command a running pluto.  whack uses a UNIX domain
       socket to speak to pluto (by default, /var/pluto.ctl).

       whack has an  intricate  argument  syntax.   This  syntax  allows  many
       different  functions to be specified.  The help form shows the usage or
       version information.  The connection form gives pluto a description  of
       a  potential  connection.  The public key form informs pluto of the RSA
       public key for a potential peer.  The delete form deletes a  connection
       description  and  all  SAs  corresponding to it.  The listen form tells
       pluto to start or stop listening  on  the  public  interfaces  for  IKE
       requests  from peers.  The route form tells pluto to set up routing for
       a connection; the unroute form undoes this.  The  initiate  form  tells
       pluto  to negotiate an SA corresponding to a connection.  The terminate
       form tells pluto to remove  all  SAs  corresponding  to  a  connection,
       including those being negotiated.  The status form displays the pluto's
       internal state.  The debug form tells pluto to change the selection  of
       debugging output ``on the fly''.  The shutdown form tells pluto to shut
       down, deleting all SAs.

       Most options are specific to one of the forms, and  will  be  described
       with that form.  There are three options that apply to all forms.

       --ctlbase path
              path.ctl is used as the UNIX domain socket for talking to pluto.
              This option facilitates debugging.

       --optionsfrom filename
              adds the contents of the file to the argument list.

       --label string
              adds the string to all error messages generated by whack.

       The help form of whack is self-explanatory.

       --help display the usage message.

              display the version of whack.

       The connection form describes a potential connection to  pluto.   pluto
       needs  to  know  what  connections  can and should be negotiated.  When
       pluto is the initiator, it needs to know what to propose.   When  pluto
       is  the  responder,  it  needs  to  know enough to decide whether is is
       willing to set up the proposed connection.

       The description of a potential connection can specify a large number of
       details.   Each connection has a unique name.  This name will appear in
       a updown shell command, so it should not contain punctuation that would
       make the command ill-formed.

       --name connection-name

       The  topology  of  a  connection is symmetric, so to save space here is
       half a picture:


       A similar trick is used in the flags.  The same flag names are used for
       both ends.  Those before the --to flag describe the left side and those
       afterwards describe the right side.  When pluto  attempts  to  use  the
       connection, it decides whether it is the left side or the right side of
       the connection, based on the IP numbers of its interfaces.

       --id id
              the identity of the end.  Currently, this can be an  IP  address
              (specified  as  dotted quad or as a Fully Qualified Domain Name,
              which will be resolved immediately)  or  as  a  Fully  Qualified
              Domain  Name itself (prefixed by ``@'' to signify that it should
              not be resolved), or as user@FQDN, or as the magic value  %myid.
              Pluto  only  authenticates the identity, and does not use it for
              addressing, so, for example, an IP address need not be  the  one
              to  which  packets are to be sent.  If the option is absent, the
              identity defaults to the IP address specified by --host.   %myid
              allows  the identity to be separately specified (by the pluto or
              whack  option  --myid  or  by  the  ipsec.conf(5)  config  setup
              parameter  myid).   Otherwise,  pluto  tries to guess what %myid
              should stand for: the IP address  of  %defaultroute,  if  it  is
              supported  by  a  suitable  TXT record in the reverse domain for
              that IP address, or the system's hostname, if it is supported by
              a suitable TXT record in its forward domain.

       --host ipaddress

       --host %any

       --host %opportunistic
              the  IP address of the end (generally the public interface).  If
              pluto is to act as a responder for  IKE  negotiations  initiated
              from  unknown  IP  addresses (the ``Road Warrior'' case), the IP
              address should be specified as  %any  (currently,  the  obsolete
              notation  is  also  accepted for this).  If pluto is to
              opportunistically initiate the connection, use %opportunistic

       --ikeport portnumber
              the UDP port that IKE listens to on that host.  The  default  is
              500.   (pluto on this machine uses the port specified by its own
              command line argument, so this only affects  where  pluto  sends

       --nexthop ipaddress
              where to route packets for the peer's client (presumably for the
              peer too, but it  will  not  be  used  for  this).   When  pluto
              installs  an  IPsec  SA, it issues a route command.  It uses the
              nexthop as the gateway.  The default is the  peer's  IP  address
              (this  can  be  explicitly  written  as  %direct;  the  obsolete
              notation is accepted).   This  option  is  necessary  if
              pluto's host's interface used for sending packets to the peer is
              neither point-to-point nor directly connected to the peer.

       --client subnet
              the subnet for which the IPsec traffic will be destined.  If not
              specified,  the  host  will  be  the  client.  The subnet can be
              specified in any of the forms supported  by  ipsec_atosubnet(3).
              The  general  form is address/mask.  The address can be either a
              domain  name  or  four  decimal  numbers   (specifying   octets)
              separated  by  dots.   The most convenient form of the mask is a
              decimal integer, specifying the number of leading  one  bits  in
              the mask.  So, for example, would specify the class A
              network ``Net 10''.

              specifies that when an RSA public key is needed to  authenticate
              this host, and it isn't already known, fetch it from DNS.

       --updown updown
              specifies  an  external  shell  command to be run whenever pluto
              brings up or down a connection.  The script is used to  build  a
              shell  command,  so  it  may  contain positional parameters, but
              ought not to have punctuation that  would  cause  the  resulting
              command to be ill-formed.  The default is ipsec _updown.

       --to   separates  the  specification  of the left and right ends of the

       The potential connection description also specifies characteristics  of
       rekeying and security.

       --psk  Propose and allow preshared secret authentication for IKE peers.
              This authentication requires that each side use the same secret.
              May be combined with --rsasig; at least one must be specified.

              Propose  and  allow  RSA  signatures  for  authentication of IKE
              peers.  This authentication requires that each side have have  a
              private key of its own and know the public key of its peer.  May
              be combined with --psk; at least one must be specified.

              All proposed or accepted IPsec SAs will  include  non-null  ESP.
              The actual choices of transforms are wired into pluto.

              All  proposed IPsec SAs will include AH.  All accepted IPsec SAs
              will include AH or ESP with authentication.  The actual  choices
              of  transforms are wired into pluto.  Note that this has nothing
              to do with IKE authentication.

              All proposed IPsec SAs will include IPCOMP (compression).   This
              will  be  ignored  if  the  kernel is not configured with IPCOMP

              the IPsec SA should use tunneling.  Implicit if the  SA  is  for
              clients.  Must only be used with --authenticate or --encrypt.

       --ipv4 The  host addresses will be interpreted as IPv4 addresses.  This
              is the default.  Note that for a connection, all host  addresses
              must  be of the same Address Family (IPv4 and IPv6 use different
              Address Families).

       --ipv6 The host addresses (including nexthop) will  be  interpreted  as
              IPv6  addresses.  Note that for a connection, all host addresses
              must be of the same Address Family (IPv4 and IPv6 use  different
              Address Families).

              The client addresses will be interpreted as IPv4 addresses.  The
              default is to match what the host will be.  This does not  imply
              --tunnel  so  the  flag  can  be  safely  used when no tunnel is
              actually specified.  Note that  for  a  connection,  all  tunnel
              addresses must be of the same Address Family.

              The client addresses will be interpreted as IPv6 addresses.  The
              default is to match what the host will be.  This does not  imply
              --tunnel  so  the  flag  can  be  safely  used when no tunnel is
              actually specified.  Note that  for  a  connection,  all  tunnel
              addresses must be of the same Address Family.

       --pfs  There  should  be  Perfect Forward Secrecy - new keying material
              will be generated for each IPsec SA rather  than  being  derived
              from  the ISAKMP SA keying material.  Since the group to be used
              cannot be negotiated (a dubious feature of the standard),  pluto
              will  propose  the  same group that was used during Phase 1.  We
              don't implement a stronger form of PFS which would require  that
              the ISAKMP SA be deleted after the IPSEC SA is negotiated.

              If  the  connection  is a tunnel, allow packets arriving through
              the tunnel to have any source and destination addresses.

       If none of the --encrypt, --authenticate, --compress, or --pfs flags is
       given, the initiating the connection will only build an ISAKMP SA.  For
       such a connection, client subnets have  no  meaning  and  must  not  be

       More  work  is needed to allow for flexible policies.  Currently policy
       is hardwired in the source file spdb.c.  The ISAKMP SAs may use  Oakley
       groups  MODP1024  and  MODP1536;  3DES  encryption;  SHA1-96 and MD5-96
       authentication.  The IPsec SAs may use 3DES and MD5-96 or  SHA1-96  for
       ESP,  or  just  MD5-96 or SHA1-96 for AH.  IPCOMP Compression is always

       --ikelifetime seconds
              how long pluto will propose that an  ISAKMP  SA  be  allowed  to
              live.   The  default  is  10800 (three hours) and the maximum is
              86400 (one day).  This option will not affect what is  accepted.
              pluto will reject proposals that exceed the maximum.

       --ipseclifetime seconds
              how long pluto will propose that an IPsec SA be allowed to live.
              The default is 3600 (one hour) and the  maximum  is  86400  (one
              day).  This option will not affect what is accepted.  pluto will
              reject proposals that exceed the maximum.

       --rekeymargin seconds
              how long before an SA's expiration should pluto try to negotiate
              a  replacement  SA.   This  will  only  happen  if pluto was the
              initiator.  The default is 540 (nine minutes).

       --rekeyfuzz percentage
              maximum  size  of  random  component  to  add  to   rekeymargin,
              expressed  as  a percentage of rekeymargin.  pluto will select a
              delay uniformly distributed within this range.  By default,  the
              percentage  will  be  100.   If  greater determinism is desired,
              specify 0.  It may be appropriate for the percentage to be  much
              larger than 100.

       --keyingtries count
              how  many  times pluto should try to negotiate an SA, either for
              the first time or for rekeying.  A value of 0 is interpreted  as
              a very large number: never give up.  The default is three.

              A  misnomer.   Only  rekey a connection if we were the Initiator
              and there was recent traffic on the existing  connection.   This
              applies  to  Phase  1  and  Phase 2.  This is currently the only
              automatic way for a connection to terminate.  It may  be  useful
              with Road Warrior or Opportunistic connections.
              Since   SA   lifetime  negotiation  is  take-it-or-leave  it,  a
              Responder normally uses the shorter of  the  negotiated  or  the
              configured lifetime.  This only works because if the lifetime is
              shorter than negotiated, the Responder will  rekey  in  time  so
              that  everything  works.  This interacts badly with --dontrekey.
              In this case, the Responder will end up rekeying  to  rectify  a
              shortfall  in  an  IPsec  SA  lifetime;  for  an  ISAKMP SA, the
              Responder will accept the negotiated lifetime.

              when used  in  the  connection  form,  it  causes  any  previous
              connection  with  this  name  to  be  deleted before this one is
              added.  Unlike a normal delete, no  diagnostic  is  produced  if
              there  was  no  previous  connection  to delete.  Any routing in
              place for the connection is undone.

       The delete form deletes a named  connection  description  and  any  SAs
       established  or  negotiations  initiated  using  this  connection.  Any
       routing in place for the connection is undone.


       --name connection-name

       The deletestate form deletes the state object with the specified serial
       number.    This   is  useful  for  selectively  deleting  instances  of

       --deletestate state-number

       The route form of the whack command tells pluto to set up routing for a
       connection.  Although like a traditional route, it uses an ipsec device
       as a virtual interface.  Once routing is set up,  no  packets  will  be
       sent ``in the clear'' to the peer's client specified in the connection.
       A TRAP shunt eroute will be installed; if outbound traffic  is  caught,
       Pluto  will  initiate  the  connection.  An explicit whack route is not
       always needed: if it hasn't  been  done  when  an  IPsec  SA  is  being
       installed, one will be automatically attempted.

       When a routing is attempted for a connection, there must not already be
       a routing for a different connection with the same subnet but different
       interface  or destination, or if there is, it must not be being used by
       an IPsec SA.  Otherwise the attempt will fail.


       --name connection-name

       The unroute form of the whack command tells pluto to  undo  a  routing.
       pluto  will  refuse if an IPsec SA is using the connection.  If another
       connection is sharing the same routing,  it  will  be  left  in  place.
       Without   a  routing,  packets  will  be  sent  without  encryption  or


       --name connection-name

       The initiate form tells pluto to initiate a  negotiation  with  another
       pluto  (or  other  IKE  daemon)  according  to  the  named  connection.
       Initiation requires a route that --route would provide; if none  is  in
       place at the time an IPsec SA is being installed, pluto attempts to set
       one up.


       --name connection-name


       The initiate form of the whack  command  will  relay  back  from  pluto
       status information via the UNIX domain socket (unless --asynchronous is
       specified).  The status information is meant to look a  bit  like  that
       from  FTP.   Currently  whack  simply  copies this to stderr.  When the
       request is finished (eg. the SAs are established or  pluto  gives  up),
       pluto closes the channel, causing whack to terminate.

       The opportunistic initiate form is mainly used for debugging.



       --oppohere ip-address

       --oppothere ip-address

       This  will  cause  pluto  to  attempt  to  opportunistically initiate a
       connection from here to the there, even if a previous attempt had  been
       made.  The whack log will show the progress of this attempt.

       The terminate form tells pluto to delete any SAs that use the specified
       connection and to stop  any  negotiations  in  process.   It  does  not
       prevent  new  negotiations  from  starting  (the  delete  form has this


       --name connection-name

       The public key for informs pluto of the RSA public key for a  potential
       peer.   Private  keys  must  be  kept  secret,  so  they  are  kept  in

       --keyid id
              specififies the identity of the peer  for  which  a  public  key
              should  be  used.   Its form is identical to the identity in the
              connection.  If no public key is specified,  pluto  attempts  to
              find  KEY  records  from  DNS  for the id (if a FQDN) or through
              reverse lookup (if an IP  address).   Note  that  there  several
              interesting ways in which this is not secure.

              specifies that the new key is added to the collection; otherwise
              the new key replaces any old ones.

       --pubkeyrsa key
              specifies the value of the RSA public key.  It is a sequence  of
              bytes  as  described  in RFC 2537 ``RSA/MD5 KEYs and SIGs in the
              Domain Name System (DNS)''.  It is denoted in a way suitable for
              ipsec_ttodata(3).   For  example,  a base 64 numeral starts with

       The listen form tells pluto to start listening for IKE requests on  its
       public  interfaces.  To avoid race conditions, it is normal to load the
       appropriate connections into pluto before allowing it  to  listen.   If
       pluto  isn't listening, it is pointless to initiate negotiations, so it
       will refuse requests to do so.  Whenever the listen form is used, pluto
       looks  for  public  interfaces  and will notice when new ones have been
       added and when old ones have been removed.  This is  also  the  trigger
       for  pluto  to  read the ipsec.secrets file.  So listen may useful more
       than once.

              start listening for IKE traffic on public interfaces.

              stop listening for IKE traffic on public interfaces.

       The status form will display information about the  internal  state  of
       pluto:  information  about  each potential connection, about each state
       object, and  about  each  shunt  that  pluto  is  managing  without  an
       associated connection.


       The  shutdown  form is the proper way to shut down pluto.  It will tear
       down the SAs on this machine that pluto has negotiated.   It  does  not
       inform its peers, so the SAs on their machines remain.


       It  would  be normal to start pluto in one of the system initialization
       scripts.  It needs to be run by the superuser.  Generally, no arguments
       are needed.  To run in manually, the superuser can simply type

          ipsec pluto

       The  command  will immediately return, but a pluto process will be left
       running, waiting for requests from whack or a peer.

       Using whack, several potential connections would be described:

          ipsec whack --name silly --host --to --host
              --ikelifetime 900 --ipseclifetime 800 --keyingtries 3

       Since  this  silly connection description specifies neither encryption,
       authentication, nor tunneling, it could only be used  to  establish  an
       ISAKMP SA.

          ipsec whack --name secret --host --client --to
              --host --client --encrypt

       This is something that must be done on both sides.  If the  other  side
       is  pluto,  the  same  whack  command  could be used on it (the command
       syntax is designed to not distinguish which end is ours).

       Now that the connections  are  specified,  pluto  is  ready  to  handle
       requests  and  replies  via  the public interfaces.  We must tell it to
       discover those interfaces and start accepting messages from peers:

          ipsec whack --listen

       If we don't immediately wish to bring up a  secure  connection  between
       the  two  clients,  we  might  wish  to  prevent insecure traffic.  The
       routing form asks pluto to cause the packets sent from  our  client  to
       the  peer's  client to be routed through the ipsec0 device; if there is
       no SA, they will be discarded:

          ipsec whack --route secret

       Finally, we are ready to get pluto to initiate negotiation for an IPsec
       SA (and implicitly, an ISAKMP SA):

          ipsec whack --initiate --name secret

       A small log of interesting events will appear on standard output (other
       logging is sent to syslog).

       whack can also be used to terminate pluto cleanly, tearing down all SAs
       that it has negotiated.

          ipsec whack --shutdown

       Notification  of  any  IPSEC SA deletion, but not ISAKMP SA deletion is
       sent to the peer.  Unfortunately, such Notification  is  not  reliable.
       Furthermore, pluto itself ignores Notifications.

   The updown command
       Whenever  pluto  brings  a connection up or down, it invokes the updown
       command.  This command is specified using the  --updown  option.   This
       allows for customized control over routing and firewall manipulation.

       The  updown  is  invoked  for five different operations.  Each of these
       operations can be for our client subnet or for our host itself.

       prepare-host or prepare-client
              is  run  before  bringing  up  a  new  connection  if  no  other
              connection  with  the  same  clients  is up.  Generally, this is
              useful for deleting a route that might have been set  up  before
              pluto was run or perhaps by some agent not known to pluto.

       route-host or route-client
              is  run  when  bringing  up  a  connection for a new peer client
              subnet (even if prepare-host or prepare-client  was  run).   The
              command  should install a suitable route.  Routing decisions are
              based only on the destination (peer's  client)  subnet  address,
              unlike eroutes which discriminate based on source too.

       unroute-host or unroute-client
              is  run  when bringing down the last connection for a particular
              peer client subnet.  It  should  undo  what  the  route-host  or
              route-client did.

       up-host or up-client
              is  run  when  bringing up a tunnel eroute with a pair of client
              subnets that does  not  already  have  a  tunnel  eroute.   This
              command  should  install  firewall  rules as appropriate.  It is
              generally a good idea to  allow  IKE  messages  (UDP  port  500)
              travel between the hosts.

       down-host or down-client
              is  run  when  bringing  down  the  eroute  for a pair of client
              subnets.   This  command  should  delete   firewall   rules   as
              appropriate.   Note that there may remain some inbound IPsec SAs
              with these client subnets.

       The script is passed a large number of environment variables to specify
       what needs to be done.

              indicates  what  version  of this interface is being used.  This
              document describes version 1.1.   This  is  upwardly  compatible
              with version 1.0.

              specifies  the  name  of the operation to be performed (prepare-
              host,r prepare-client, up-host, up-client, down-host,  or  down-
              client).  If the address family for security gateway to security
              gateway communications is IPv6, then a suffix of -v6 is added to
              the verb.

              is the name of the connection for which we are routing.

              is  the  next  hop  to  which packets bound for the peer must be

              is the name of the ipsec interface to be used.

              is the IP address of our host.

              is the IP address / count of our client subnet.  If  the  client
              is  just  the host, this will be the host's own IP address / max
              (where max is 32 for IPv4 and 128 for IPv6).

              is the IP address of our client net.  If the client is just  the
              host, this will be the host's own IP address.

              is the mask for our client net.  If the client is just the host,
              this will be

              is the IP address of our peer.

              is the IP address / count of the peer's client subnet.   If  the
              client  is just the peer, this will be the peer's own IP address
              / max (where max is 32 for IPv4 and 128 for IPv6).

              is the IP address of the peer's client net.  If  the  client  is
              just the peer, this will be the peer's own IP address.

              is  the  mask  for the peer's client net.  If the client is just
              the peer, this will be

       All output sent by the script to  stderr  or  stdout  is  logged.   The
       script should return an exit status of 0 if and only if it succeeds.

       Pluto  waits  for  the  script  to  finish  and  will  not do any other
       processing while it is waiting.  The script may assume that pluto  will
       not  change  anything  while  the script runs.  The script should avoid
       doing anything that takes much time and it should not issue any command
       that requires processing by pluto.  Either of these activities could be
       performed by a background subprocess of the script.

       When an SA that was initiated by pluto has only a bit of lifetime left,
       pluto  will  initiate the creation of a new SA.  This applies to ISAKMP
       and IPsec SAs.  The rekeying will be initiated when the SA's  remaining
       lifetime is less than the rekeymargin plus a random percentage, between
       0 and rekeyfuzz, of the rekeymargin.

       Similarly, when an SA that was initiated by the peer has only a bit  of
       lifetime   left,   pluto  will  try  to  initiate  the  creation  of  a
       replacement.  To give preference to the initiator, this  rekeying  will
       only  be  initiated  when  the  SA's  remaining  lifetime  is  half  of
       rekeymargin.  If rekeying is done by the responder, the roles  will  be
       reversed:  the  responder  for the old SA will be the initiator for the
       replacement.  The former initiator might  also  initiate  rekeying,  so
       there may be redundant SAs created.  To avoid these complications, make
       sure that rekeymargin is generous.

       One risk of having the former responder initiate is that  perhaps  none
       of  its  proposals is acceptable to the former initiator (they have not
       been used in a successful negotiation).  To reduce the chances of  this
       happening,  and  to  prevent  loss of security, the policy settings are
       taken from the old SA (this is the case even if the former initiator is
       initiating).  These may be stricter than those of the connection.

       pluto  will  not  rekey  an SA if that SA is not the most recent of its
       type (IPsec or ISAKMP)  for  its  potential  connection.   This  avoids
       creating redundant SAs.

       The  random  component  in the rekeying time (rekeyfuzz) is intended to
       make certain pathological patterns of rekeying unstable.  If both sides
       decide  to  rekey  at the same time, twice as many SAs as necessary are
       created.  This could become a stable pattern without the randomness.

       Another more important case occurs when a security gateway has SAs with
       many  other security gateways.  Each of these connections might need to
       be rekeyed at the same time.  This would cause a high peek  requirement
       for   resources  (network  bandwidth,  CPU  time,  entropy  for  random
       numbers).  The rekeyfuzz can be used to stagger the rekeying times.

       Once a new set of SAs  has  been  negotiated,  pluto  will  never  send
       traffic  on  a  superseded  one.  Traffic will be accepted on an old SA
       until it expires.

   Selecting a Connection When Responding: Road Warrior Support
       When pluto receives an initial Main Mode message, it  needs  to  decide
       which  connection  this  message  is for.  It picks based solely on the
       source and destination IP addresses of the  message.   There  might  be
       several  connections  with  suitable IP addresses, in which case one of
       them is arbitrarily chosen.  (The ISAKMP SA proposal contained  in  the
       message could be taken into account, but it is not.)

       The ISAKMP SA is negotiated before the parties pass further identifying
       information,  so  all  ISAKMP  SA  characteristics  specified  in   the
       connection description should be the same for every connection with the
       same two host IP addresses.  At the  moment,  the  only  characteristic
       that might differ is authentication method.

       Up  to  this  point, all configuring has presumed that the IP addresses
       are known to all parties ahead of time.  This will not work when either
       end is mobile (or assigned a dynamic IP address for other reasons).  We
       call this situation ``Road Warrior''.  It is fairly tricky and has some
       important limitations, most of which are features of the IKE protocol.

       Only  the  initiator may be mobile: the initiator may have an IP number
       unknown to the responder.  When the responder doesn't recognize the  IP
       address  on  the first Main Mode packet, it looks for a connection with
       itself as one end and %any as the other.  If it  cannot  find  one,  it
       refuses  to  negotiate.   If  it  does find one, it creates a temporary
       connection that is a duplicate except with the  %any  replaced  by  the
       source  IP  address from the packet; if there was no identity specified
       for the peer, the new IP address will be used.

       When pluto is using one of these temporary  connections  and  needs  to
       find  the preshared secret or RSA private key in ipsec.secrets, and and
       the connection specified no identity for the peer, %any is used as  its
       identity.  After all, the real IP address was apparently unknown to the
       configuration, so it is unreasonable to require that it be used in this

       Part  way  into  the Phase 1 (Main Mode) negotiation using one of these
       temporary connection descriptions, pluto will be  receive  an  Identity
       Payload.    At   this  point,  pluto  checks  for  a  more  appropriate
       connection, one with an identity for the peer that matches the  payload
       but  which  would use the same keys so-far used for authentication.  If
       it finds one, it will switch to using  this  better  connection  (or  a
       temporary derived from this, if it has %any for the peer's IP address).
       It may even turn out that no connection matches  the  newly  discovered
       identity,  including  the  current  connection; if so, pluto terminates

       Unfortunately, if preshared secret authentication is  being  used,  the
       Identity  Payload is encrypted using this secret, so the secret must be
       selected by the responder without knowing this  payload.   This  limits
       there  to  being  at  most  one  preshared  secret for all Road Warrior
       systems connecting to a host.  RSA Signature authentications  does  not
       require  that  the  responder know how to select the initiator's public
       key until after the initiator's Identity Payload is decoded (using  the
       responder's private key, so that must be preselected).

       When  pluto  is responding to a Quick Mode negotiation via one of these
       temporary connection descriptions, it may well find  that  the  subnets
       specified   by  the  initiator  don't  match  those  in  the  temporary
       connection description.  If so, it will  look  for  a  connection  with
       matching  subnets,  its  own  host  address, a peer address of %any and
       matching identities.  If it finds one, a new  temporary  connection  is
       derived  from this one and used for the Quick Mode negotiation of IPsec
       SAs.  If it does not find one, pluto terminates negotiation.

       Be sure to specify an appropriate nexthop for the responder to  send  a
       message  to  the  initiator:  pluto  has  no  way  of  guessing  it (if
       forwarding isn't required, use an explicit %direct as the  nexthop  and
       the  IP  address  of  the  initiator  will  be  filled in; the obsolete
       notation is still accepted).

       pluto has no special provision for the  initiator  side.   The  current
       (possibly  dynamic)  IP  address  and  nexthop must be used in defining
       connections.   These  must  be  properly  configured  each   time   the
       initiator's  IP  address  changes.   pluto  has no mechanism to do this

       Although we call this Road Warrior Support, it could also  be  used  to
       support   encrypted   connections   with   anonymous  initiators.   The
       responder's organization could announce the preshared secret that would
       be used with unrecognized initiators and let anyone connect.  Of course
       the initiator's identity would not be authenticated.

       If any Road Warrior connections are supported, pluto cannot  reject  an
       exchange  initiated by an unknown host until it has determined that the
       secret is not shared or the signature is invalid.  This must await  the
       third  Main  Mode  message  from  the  initiator.   If  no Road Warrior
       connection is supported, the first message from an unknown source would
       be   rejected.    This   has   implications   for   ease  of  debugging
       configurations and for denial of service attacks.

       Although a Road Warrior connection must  be  initiated  by  the  mobile
       side,  the other side can and will rekey using the temporary connection
       it has created.  If the Road Warrior wishes to be able  to  disconnect,
       it  is probably wise to set --keyingtries to 1 in the connection on the
       non-mobile  side  to  prevent  it  trying  to  rekey  the   connection.
       Unfortunately,   there  is  no  mechanism  to  unroute  the  connection

       pluto accepts several optional arguments, useful mostly for  debugging.
       Except for --interface, each should appear at most once.

       --interface interfacename
              specifies that the named real public network interface should be
              considered.  The interface name specified should not be  ipsecN.
              If the option doesn't appear, all interfaces are considered.  To
              specify several interfaces, use the option once for  each.   One
              use  of this option is to specify which interface should be used
              when two or more share the same IP address.

       --ikeport port-number
              changes the UDP port that pluto will use (default, specified  by
              IANA: 500)

       --ctlbase path
              basename  for  control  files.   path.ctl  is the socket through
              which whack communicates with pluto. is  the  lockfile
              to   prevent   multiple   pluto   instances.    The  default  is

       --secretsfile file
              specifies  the  file  for   authentication   secrets   (default:
              /etc/ipsec.secrets).  This name is subject to ``globbing'' as in
              sh(1), so every file with a matching name is processed.  Quoting
              is  generally  needed  to  prevent  the  shell  from  doing  the

       --adns pathname

       --lwdnsq pathname
              specifies where to find pluto's helper program for  asynchronous
              DNS  lookup.   pluto  can  be  built  to  use  one of two helper
              programs: _pluto_adns or lwdnsq.  You must use the  program  for
              which it was built.  By default, pluto will look for the program
              in $IPSEC_DIR (if that  environment  variable  is  defined)  or,
              failing that, in the same directory as pluto.

              disable  ``daemon  fork''  (default  is  to fork).  In addition,
              after the lock file and control socket are  created,  print  the
              line ``Pluto initialized'' to standard out.

              if  this  option  has been selected, whenever a new ISAKMP SA is
              established,  any  connection  with  the  same  Peer  ID  but  a
              different  Peer IP address is unoriented (causing all its SAs to
              be deleted).  This helps clean up dangling SAs when a connection
              is lost and then regained at another IP address.

              log goes to standard out {default is to use syslogd(8))

       pluto   is   willing  to  produce  a  prodigious  amount  of  debugging
       information.  To do so, it must be compiled with  -DDEBUG.   There  are
       several  classes  of  debugging  output,  and  pluto may be directed to
       produce a selection  of  them.   All  lines  of  debugging  output  are
       prefixed with ``| '' to distinguish them from error messages.

       When  pluto  is  invoked,  it  may  be given arguments to specify which
       classes to output.  The current options are:

              show the raw bytes of messages

              show the encryption and decryption of messages

              show the structure of input messages

              show the structure of output messages

              show pluto's decision making

              [this option is temporary] log more detail of lifecycle of SAs

              show pluto's interaction with the kernel

              show pluto's interaction with DNS for KEY and TXT records

              show why  pluto  didn't  find  a  suitable  DNS  TXT  record  to
              authorize opportunistic initiation

              all of the above

              allow debugging output with private keys.

              none of the above

       The  debug  form  of  the  whack command will change the selection in a
       running pluto.  If a connection name is specified, the flags are  added
       whenever  pluto has identified that it is dealing with that connection.
       Unfortunately,  this  is  often  part  way  into  the  operation  being

       For  example, to start a pluto with a display of the structure of input
       and output:

              pluto --debug-emitting --debug-parsing

       To later change this pluto to only display raw bytes:

              whack --debug-raw

       For testing, SSH's IKE test page is quite useful:


       Hint: ISAKMP SAs are often kept alive by IKEs even after the  IPsec  SA
       is  established.   This  allows  future  IPsec  SA's  to  be negotiated
       directly.  If one of the IKEs is restarted, the other may  try  to  use
       the  ISAKMP  SA  but the new IKE won't know about it.  This can lead to
       much confusion.  pluto is not yet smart enough to get  out  of  such  a

   Pluto's Behaviour When Things Go Wrong
       When  pluto doesn't understand or accept a message, it just ignores the
       message.  It is not yet capable of communicating  the  problem  to  the
       other  IKE  daemon  (in  the  future  it  might  use  Notifications  to
       accomplish this in many cases).  It does log a diagnostic.

       When pluto gets no response from a message, it resends the same message
       (a message will be sent at most three times).  This is appropriate: UDP
       is unreliable.

       When pluto gets a message that it has  already  seen,  there  are  many
       cases  when  it  notices  and discards it.  This too is appropriate for

       Combine  these  three  rules,  and  you  can  explain  many  apparently
       mysterious  behaviours.   In  a  pluto  log, retrying isn't usually the
       interesting event.  The critical thing is either earlier (pluto  got  a
       message  which  it didn't like and so ignored, so it was still awaiting
       an acceptable message and got impatient) or on the other system  (pluto
       didn't send a reply because it wasn't happy with the previous message).

       Each  IPsec SA is assigned an SPI, a 32-bit number used to refer to the
       SA.  The IKE protocol lets the destination of the SA  choose  the  SPI.
       The  range  0 to 0xFF is reserved for IANA.  Pluto also avoids choosing
       an SPI in the range 0x100 to 0xFFF, leaving these SPIs free for  manual
       keying.   Remember  that the peer, if not pluto, may well chose SPIs in
       this range.

       This catalogue of policies may be of use when trying to configure Pluto
       and another IKE implementation to interoperate.

       In  Phase  1,  only  Main  Mode  is  supported.   We  are not sure that
       Aggressive Mode is secure.  For one thing, it does not support identity
       protection.  It may allow more severe Denial Of Service attacks.

       No Informational Exchanges are supported.  These are optional and since
       their delivery is not assured, they must not matter.  It  is  the  case
       that  some IKE implementations won't interoperate without Informational
       Exchanges, but we feel they are broken.

       No Informational Payloads  are  supported.   These  are  optional,  but
       useful.   It is of concern that these payloads are not authenticated in
       Phase 1, nor in those Phase 2 messages authenticated with HASH(3).

       · Diffie Hellman  Groups  MODP  1024  and  MODP  1536  (2  and  5)  are
         supported.   Group  MODP768  (1)  is  not supported because it is too

       · Host authetication can  be  done  by  RSA  Signatures  or  Pre-Shared

       · 3DES  CBC  (Cypher  Block  Chaining  mode)  is  the  only  encryption
         supported, both for ISAKMP SAs and IPSEC SAs.

       · MD5 and SHA1 hashing are supported for packet authentication in  both
         kinds of SAs.

       · The  ESP,  AH, or AH plus ESP are supported.  If, and only if, AH and
         ESP are combined, the  ESP  need  not  have  its  own  authentication
         component.    The  selection  is  controlled  by  the  --encrypt  and
         --authenticate flags.

       · Each of these may be combined with IPCOMP  Deflate  compression,  but
         only  if  the  potential connection specifies compression and only if
         the kernel is configured with IPCOMP support.

       · The IPSEC SAs may be tunnel or  transport  mode,  where  appropriate.
         The --tunnel flag controls this when pluto is initiating.

       · When  responding  to  an  ISAKMP  SA proposal, the maximum acceptable
         lifetime is eight hours.  The default  is  one  hour.   There  is  no
         minimum.    The  --ikelifetime  flag  controls  this  when  pluto  is

       · When responding to an  IPSEC  SA  proposal,  the  maximum  acceptable
         lifetime  is  one  day.   The  default  is  eight hours.  There is no
         minimum.  The  --ipseclifetime  flag  controls  this  when  pluto  is

       · PFS  is  acceptable,  and  will  be  proposed  if  the --pfs flag was
         specified.  The DH group proposed will be the same as negotiated  for
         Phase 1.


       Pluto   responds  to  SIGHUP  by  issuing  a  suggestion  that  ``whack
       --listen'' might have been intended.

       Pluto exits when it recieves SIGTERM.


       pluto normally forks a daemon process, so the exit status is normally a
       very preliminary result.

       0      means that all is OK so far.

       1      means that something was wrong.

       10     means that the lock file already exists.

       If  whack detects a problem, it will return an exit status of 1.  If it
       received progress messages from pluto, it returns as status  the  value
       of the numeric prefix from the last such message that was not a message
       sent to syslog or a comment (but the prefix for success is  treated  as
       0).  Otherwise, the exit status is 0.






       The rest of the FreeS/WAN distribution, in particular ipsec(8).

       ipsec_auto(8) is designed to make using pluto more pleasant.  Use it!

       ipsec.secrets(5) describes the format of the secrets file.

       ipsec_atoaddr(3),  part  of  the  FreeS/WAN distribution, describes the
       forms that IP addresses may  take.   ipsec_atosubnet(3),  part  of  the
       FreeS/WAN distribution, describes the forms that subnet specifications.

       For  more  information  on  IPsec,  the  mailing list, and the relevant
       documents, see:


       At the time of writing, the most relevant IETF RFCs are:

              RFC2409 The Internet Key Exchange (IKE)

              RFC2408   Internet   Security  Association  and  Key  Management
              Protocol (ISAKMP)

              RFC2407 The Internet IP Security Domain  of  Interpretation  for

       The  FreeS/WAN  web site <htp://> and the mailing lists
       described there.


       This code is released under the GPL terms.  See the  accompanying  file
       COPYING-2.0  for  more details.  The GPL does NOT apply to those pieces
       of code written by others which  are  included  in  this  distribution,
       except as noted by the individual authors.

       This   software  was  originally  written  for  the  FreeS/WAN  project
       <>      by      Angelos       D.       Keromytis
       (,  in  May/June  1997,  in  Athens,  Greece.
       Thanks go to John Ioannidis for his help.

       It is currently (2000)  being  developed  and  maintained  by  D.  Hugh
       Redelmeier (, in Canada.  The regulations of Greece and
       Canada allow us to make the code freely redistributable.

       Kai  Martius  (  contributed  the  initial
       version of the code supporting PFS.

       Richard   Guy   Briggs   <>  and  Peter  Onion
       <> added the PFKEY2 support.

       We gratefully acknowledge that we use  parts  of  Eric  Young's  libdes
       package; see ../libdes/COPYRIGHT.


       pluto  is  a work-in-progress.  It currently has many limitations.  For
       example, it ignores notification messages  that  it  receives,  and  it
       generates only Delete Notifications and those only for IPSEC SAs.

       pluto  does  not  support  the  Commit  Flag.  The Commit Flag is a bad
       feature of the IKE protocol.  It isn't protected --  neither  encrypted
       nor  authenticated.   A  man in the middle could turn it on, leading to
       DoS.   We  just  ignore  it,  with  a  warning.   This  should  let  us
       interoperate with implementations that insist on it, with minor damage.

       pluto  does not check that the SA returned by the Responder is actually
       one that was proposed.  It only checks that the SA is acceptable.   The
       difference  is  not  large,  but  can  show up in attributes such as SA

       There is no good way for a connection to be  automatically  terminated.
       This  is a problem for Road Warrior and Opportunistic connections.  The
       --dontrekey option does prevent the SAs from being rekeyed  on  expiry.
       Additonally,  if  a  Road Warrior connection has a client subnet with a
       fixed IP address, a negotiation with that subnet will cause  any  other
       connection  instantiations  with  that  same  subnet  to  be unoriented
       (deleted, in effect).  See also the --uniqueids option for an extension
       of this.

       When  pluto  sends  a  message  to  a  peer that has disappeared, pluto
       receives incomplete  information  from  the  kernel,  so  it  logs  the
       unsatisfactory  message  ``some  IKE  message we sent has been rejected
       with ECONNREFUSED (kernel supplied no details)''.  John Denker suggests
       that  this  command  is  useful  for  tracking down the source of these
            tcpdump -i eth0 icmp[0] != 8 and icmp[0] != 0
       Substitute your public interface for eth0 if it is different.

       The word ``authenticate'' is used for two different features.  We  must
       authenticate  each IKE peer to the other.  This is an important task of
       Phase 1.  Each packet must be authenticated, both in IKE and in  IPsec,
       and  the  method  for IPsec is negotiated as an AH SA or part of an ESP
       SA.  Unfortunately, the protocol has no  mechanism  for  authenticating
       the Phase 2 identities.

       Bugs should be reported to the <> mailing list.
       Caution: we cannot accept actual code from US  residents,  or  even  US
       citizens  living  outside  the  US,  because that would bring FreeS/WAN
       under US export law.  Some other countries cause similar problems.   In
       general,  we would prefer that you send detailed problem reports rather
       than code:  we want FreeS/WAN to be unquestionably  freely  exportable,
       which means being very careful about where the code comes from, and for
       a  small  bug  fix,  that  is  often  more  time-consuming  than   just
       reinventing the fix ourselves.

                                 28 March 1999                  IPSEC_PLUTO(8)