IPSEC_PLUTO(8) Executable programs IPSEC_PLUTO(8)
ipsec_pluto, ipsec_whack, pluto - ipsec whack : IPsec IKE keying daemon and control interface
ipsec pluto [--help] [--version] [--leak-detective] [--config filename] [--vendorid VID] [--nofork] [--stderrlog] [----plutostderrlogtime] [--logfile filename] [--use-klips]
[--use-mast] [--use-netkey] [--use-nostack] [--uniqueids] [--virtual-private network_list] [--keep-alive delay_sec] [--force-busy] [--nocrsend] [--strictcrlpolicy]
[--crlcheckinterval] [--interface interfacename] [--listen ipaddr] [--ikeport portnumber] [--natikeport portnumber] [--ctlbase path] [--secretsfile secrets-file]
[--adns pathname] [--nhelpers number] [--seedbits numbits] [--perpeerlog] [--perpeerlogbase dirname] [--ipsecdir dirname] [--coredir dirname] [--statsbin filename]
ipsec whack [--help] [--version]
ipsec whack [--debug-none] [--debug-all] [--debug-raw] [--debug-crypt] [--debug-parsing] [--debug-emitting] [--debug-control] [--debug-lifecycle] [--debug-kernel] [--debug-pfkey]
[--debug-nat-t] [--debug-dpd] [--debug-dns] [--debug-oppo] [--debug-oppoinfo] [--debug-whackwatch] [--debug-private] [--debug-x509]
ipsec whack --name connection-name [[--ipv4] | [--ipv6]] [[--tunnelipv4] | [--tunnelipv6]]
[--id identity] [--host ip-address] [--cert path] [--ca distinguished name] [--groups access control groups] [--sendcert yes | forced | always | ifasked | no | never]
[--sendca none | issuer | all] [--certtype number] [--ikeport portnumber] [--nexthop ip-address] [[--client subnet] | [--clientwithin subnet]]
[--clientprotoport protocol/port] [--srcip ip-address] [--xauthserver] [--xauthclient] [--modecfgserver] [--modecfgclient] [--modecfgdns1 ip-address]
[--modecfgdns2 ip-address] [--modecfgdomain DNS-domain] [--modecfgbanner login-banner] [--dnskeyondemand] [--updown updown]
[--id identity] [--host ip-address] [--cert path] [--ca distinguished name] [--groups access control groups] [--sendcert yes | always | ifasked | no | never]
[--certtype number] [--ikeport port-number] [--nexthop ip-address] [--client subnet] [--clientwithin subnet] [--clientprotoport protocol/port] [--srcip ip-address]
[--xauthserver] [--xauthclient] [--modecfgserver] [--modecfgclient] [--modecfgdns1 ip-address] [--modecfgdns2 ip-address] [--modecfgdomain DNS-domain] [--dnskeyondemand]
[--tunnel] [--psk] [--rsasig] [--encrypt] [--authenticate] [--compress] [--pfs]
[--pfsgroup [modp1024] | [modp1536] | [modp2048] | [modp3072] | [modp4096] | [modp6144] | [modp8192] | [dh22] | [dh23] | [dh24]] [--disablearrivalcheck]
[--ikelifetime seconds] [--ipseclifetime seconds] [--rekeymargin seconds] [--rekeyfuzz percentage] [--keyingtries count] [--esp esp-algos] [--dontrekey] [--aggrmode]
[--modecfgpull] [--metric metric] [--nflog-group nflognum] [[--dpddelay seconds] | [--dpdtimeout seconds]] [--dpdaction [clear] | [hold] | [restart]] [--forceencaps]
[--no-keep-alive] [[--initiateontraffic] | [--pass] | [--drop] | [--reject]] [[--failnone] | [--failpass] | [--faildrop] | [--failreject]] [--ctlbase path] [--label string]
ipsec whack --keyid id [--addkey] [--pubkeyrsa key] [--ctlbase path] [--label string]
ipsec whack --myid id
ipsec whack --listen | --unlisten [--ctlbase path] [--label string]
ipsec whack --busy | --relax [--ctlbase path]
ipsec whack --route | --unroute --name connection-name [--ctlbase path] [--label string]
ipsec whack --initiate | --terminate --name connection-name [--xauthuser user] [--xauthpass pass] [--asynchronous] [--ctlbase path] [--label string]
ipsec whack [[--tunnelipv4] | [--tunnelipv6]] --oppohere ip-address --oppothere ip-address
ipsec whack --crash [ipaddress]
ipsec whack --whackrecord [filename]
ipsec whack --whackstoprecord
ipsec whack --name connection-name --delete [--ctlbase path] [--label string]
ipsec whack --deletestate state-number [--ctlbase path] [--label string]
ipsec whack --deleteuser --name username [--ctlbase path] [--label string]
ipsec whack [--name connection-name] [--debug-none] [--debug-all] [--debug-raw] [--debug-crypt] [--debug-parsing] [--debug-emitting] [--debug-control] [--debug-controlmore]
[--debug-lifecycle] [--debug-klips] [--debug-pfkey] [--debug-dns] [--debug-dpd] [--debug-natt] [--debug-oppo] [--debug-oppoinfo] [--debug-whackwatch] [--debug-private]
[--impair-bust-mi2] [--impair-bust-mr2] [--impair-sa-fail] [--impair-die-oninfo] [--impair-jacob-two-two] [--impair-major-version-bump] [--impair-minor-version-bump]
[--impair-retransmits] [--impair-send-bogus-isakmp-flag] [--impair-send-ikev2-ke] [--impair-send-key-size-check] [--impair-send-no-delete]
ipsec whack [--utc] [--listall] [--listpubkeys] [--listcerts] [--listcacerts] [--listcrls]
ipsec whack [--utc] [--rereadsecrets] [--rereadcrls] [--rereadall]
ipsec whack --listevents
ipsec whack --purgeocsp
ipsec whack --status [--ctlbase path] [--label string]
ipsec whack --trafficstatus --shuntstatus [--ctlbase path] [--label string]
ipsec whack --shutdown [--ctlbase path] [--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 other parts of the system - the kernel. Pluto can talk to various kernel implementations, such
as KLIPS, such as NETKEY, and such as KAME IPsec stacks. ipsec_auto(8) provides a more convenient interface to pluto and whack.
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. Currently, Main Mode and Aggressive Mode are
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
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 system running the KLIPS or NETKEY implementation of IPsec,
or a FreeBSD/NetBSD/Mac OSX system running the KAME implementation of IPsec.
pluto implements a large subset of IKE. This is enough for it to interoperate with other instances of pluto, and many other IKE implementations.
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. These RSA signatures can come from DNS(SEC), a configuration file, or from X.509
and CA certificates.
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 KLIPS 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 kernel to implement it. If necessary, it also invokes a script to
adjust any firewall and issue route(8) commands to direct IP packets.
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 working IPsec stack.
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. Each interface with a name of the form ipsec[0-9] is taken as a KLIPS virtual public interface. Another network
interface with the same IP address (the first one found will be used) is taken as the corresponding real public interface. The --listen can be used to limit listening on only 1
IP address of a certain interface. ifconfig(8) or ip(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.
Setting up KLIPS for pluto
The most basic network topology that pluto supports has two security gateways negotiating on behalf of client subnets. The diagram of RGB's testbed is a good example (see
The file INSTALL in the base directory of this distribution explains how to start setting up the whole system, including KLIPS.
Make sure that the security gateways have routes to each other. This is usually covered by the default route, but may require issuing route(8) commands. The route must go through
a particular IP interface (we will assume it is eth0, but it need not be). The interface that connects the security gateway to its client must be a different one.
It is necessary to issue a ipsec_tncfg(8) command on each gateway. The required command is:
ipsec tncfg --attach --virtual ipsec0 --physical eth0
A command to set up the ipsec0 virtual interface will also need to be run. It will have the same parameters as the command used to set up the physical interface to which it has
just been connected using ipsec_tncfg(8).
Setting up NETKEY for pluto
No special requirements are necessary to use NETKEY - it ships with all modern versions of Linux 2.4 and 2.6. however, note that certain vendors or older distributions use old
versions or backports of NETKEY which are broken. If possible use a NETKEY version that is at least based on, or backported from Linux 2.6.11 or newer.
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 XAUTH passwords. RSA private keys, X.509 certificates, CRLs, OCSP and smartcards are handled via NSS. For
debugging, there is an argument to the pluto command to use a different file. This file is described in ipsec.secrets(5).
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. If pluto is told to enable NAT-Traversal, then UDP port 4500 is also taken by pluto to listen on.
Pluto supports different IPstacks on different operating systems. This can be configured using one of the options --use-netkey (the default), --use-klips, --use-mast,
--use-bsdkame, --use-win2k or --use-nostack. The latter is meant for testing only - no actual IPsec connections will be loaded into the kernel. The option --use-auto has been
obsoleted. On startup, pluto might also read the protostack= option to select the IPsec stack to use if --config /etc/ipsec.conf is given as argument to pluto. If both --use-XXX
and --config /etc/ipsec.conf are specified, the last command line argument specified takes precedence.
Pluto supports RFC 3947 NAT-Traversal. The allowed range behind the NAT routers is submitted using the --virtual-private option. See ipsec.conf(5) for the syntax. The option
--force-keepalive forces the sending of the keep-alive packets, which are send to prevent the NAT router from closing its port when there is not enough traffic on the IPsec
connection. The --keep-alive sets the delay (in seconds) of these keep-alive packets. The newer NAT-T standards support port floating, and Libreswan enables this per default.
Pluto supports the use of X.509 certificates and sends it certificate when needed. This can confuse IKE implementations that do not implement this, such as the old FreeS/WAN
implementation. The --nocrsend prevents pluto from sending these. At startup, pluto loads all the X.509 related files from the directories /etc/ipsec.d/certs,
/etc/ipsec.d/cacerts, /etc/ipsec.d/aacerts, /etc/ipsec.d/private and /etc/ipsec.d/crls. The Certificate Revocation Lists can also be retrieved from an URL. The option
--crlcheckinterval sets the time between checking for CRL expiration and issuing new fetch commands. The first attempt to update a CRL is started at 2*crlcheckinterval before the
next update time. Pluto logs a warning if no valid CRL was loaded or obtained for a connection. If --strictcrlpolicy is given, the connection will be rejected until a valid CRL
has been loaded.
Pluto can also use helper children to off-load cryptographic operations. This behavior can be fine tuned using the --nhelpers. Pluto will start (n-1) of them, where n is the
number of CPU’s you have (including hypherthreaded CPU’s). A value of 0 forces pluto to do all operations in the main process. A value of -1 tells pluto to perform the above
calculation. Any other value forces the number to that amount.
Pluto uses the NSS crypto library as its random source. Some government Three Letter Agency requires that pluto reads 440 bits from /dev/random and feed this into the NSS RNG
before drawing random from the NSS library, despite the NSS library itself already seeding its internal state. As this process can block pluto for an extended time, the default
is to not perform this redundant seeding. The --seedbits option can be used to specify the number of bits that will be pulled from /dev/random and seeded into the NSS RNG. This
can also be accomplished by specifying seedbits in the "config setup" section of ipsec.conf. This option should not be used by most people.
pluto attempts to create a lockfile with the name /var/run/pluto/pluto.pid. 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 anyway).
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. In certain
configurations, pluto might also launch helper programs to assist with DNS queries or to offload cryptographic operations.
All logging, including diagnostics, is sent to syslog(3) with facility=authpriv; it decides where to put these messages (possibly in /var/log/secure or /var/log/auth.log). Since
this too can make debugging awkward, the option --stderrlog is used to steer logging to stderr.
Alternatively, --logfile can be used to send all logging information to a specific file.
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.
Pluto supports food groups, and X.509 certificates. These are located in /etc/ipsec.d, or another directory as specified by --ipsecdir.
Pluto may core dump. It will normally do so into the current working directory. You can specify the --coredir option for pluto, or specify the dumpdir= option in ipsec.conf.
If you are investigating a potential memory leak in pluto, start pluto with the --leak-detective option. Before the leak causes the system or pluto to die, shut down pluto in the
regular way. pluto will display a list of leaks it has detected.
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.
KLIPS hooks into the routing code in a LINUX kernel. Traffic to be processed by an IPsec SA must be directed through KLIPS by routing commands. Furthermore, the processing to be
done is specified by ipsec eroute(8) commands. pluto takes the responsibility of managing both of these special kinds of routes.
NETKEY requires no special routing.
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).
On KLIPS, 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 initiate).
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.
All of these routing characteristics are expected change when KLIPS and NETKEY merge into a single new stack.
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.
The crash option asks pluto to consider a particularly target IP to have crashed, and to attempt to restart all connections with that IP address as a gateway. In general, you
should use Dead Peer Detection to detect this kind of situation automatically, but this is not always possible.
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.
path.ctl is used as the UNIX domain socket for talking to pluto. This option facilitates debugging.
adds the string to all error messages generated by whack.
The help form of whack is self-explanatory.
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.
sets the name of the connection
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.
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 an X.509 DN, 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 ip-address, --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 0.0.0.0 is also accepted for this). If pluto is to opportunistically initiate the
connection, use %opportunistic
The filename of the X.509 certificate. This must be the public key certificate only, and cannot be the PKCS#12 certificate file. See ipsec.conf(5) on how to extrac this from
the PKCS#12 file.
--ca distinguished name
the X.509 Certificate Authority's Distinguished Name (DN) used as trust anchor for this connection. This is the CA certificate that signed the host certificate, as well as
the certificate of the incoming client.
--groups access control groups
the access control groups used.
Whether or not to send our X.509 certificate credentials. This could potentially give an attacker too much information about which identities are allowed to connect to this
host. The default is to use ifasked when we are a Responder, and to use yes (which is the same as forced and always if we are an Initiator. The values no and never are
equivalent. NOTE: "forced" does not seem to be actually implemented - do not use it.
How much of our available X.509 trust chain to send with the end certificate, excluding any root CAs. Specifying issuer sends just the issuing intermediate CA, while
all will send the entire chain of intermediate CAs.none will not send any CA certs. The default is none which maintains the current libreswan behavior.
The X.509 certificate type number.
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 messages.)
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 0.0.0.0 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.
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, 10.0.0.0/8 would specify the class A network “Net
This option is obsolete and will be removed. Do not use this option anymore.
specify the Port Selectors (filters) to be used on this connection. The general form is protocol/port. This is most commonly used to limit the connection to L2TP traffic only
by specifying a value of 17/1701 for UDP (protocol 17) and port 1701. The notation 17/%any can be used to allow all UDP traffic and is needed for L2TP connections with
Windows XP machines before Service Pack 2.
the IP address for this host to use when transmitting a packet to the remote IPsec gateway itself. This option is used to make the gateway itself use its internal IP, which
is part of the --client subnet. Otherwise it will use its nearest IP address, which is its public IP address, which is not part of the subnet-subnet IPsec tunnel, and would
therefor not get encrypted.
this end is an xauthserver. It will lookup the xauth user name and password and verify this before allowing the connection to get established.
this end is an xauthclient. To bring this connection up with the --initiate also requires the client to specify --xauthuser username and --xauthpass password
The username for the xauth authentication.This option is normally passed along by ipsec_auto(8) when an xauth connection is started using ipsec auto --up conn
The password for the xauth authentication. This option is normally passed along by ipsec_auto(8) when an xauth connection is started using ipsec auto --up conn
this end is an Mode Config server
this end is an Mode Config client
The IP address of the first DNS server to pass along to the ModeConfig Client
The IP address of the second DNS server to pass along to the ModeConfig Client
specifies that when an RSA public key is needed to authenticate this host, and it isn't already known, fetch it from DNS.
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. Pluto passes a dozen environment
variables to the script about the connection involved.
separates the specification of the left and right ends of the connection. Pluto tries to decide whether it is left or right based on the information provided on both sides of
The potential connection description also specifies characteristics of rekeying and security.
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 KLIPS is not configured with IPCOMP support.
the IPsec SA should use tunneling. Implicit if the SA is for clients. Must only be used with --authenticate or --encrypt.
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).
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.
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.
Sets the Diffie-Hellman group used. Currently the following values are supported: modp1024 (DHgroup 2), modp1536 (DHgroup 5), modp2048 (DHgroup 14), modp3072 (DHgroup 15),
modp4096 (DHgroup 16), modp6144 (DHgroup 17), and modp8192 (DHgroup 18). It is possible to support the weak and broken modp768 (DHgroup 1), but this requires a manual
recompile and is strongly discouraged.
If the connection is a tunnel, allow packets arriving through the tunnel to have any source and destination addresses.
ESP encryption/authentication algorithm to be used for the connection (phase2 aka IPsec SA). The options must be suitable as a value of ipsec_spi(8). See ipsec.conf(5) for a
detailed description of the algorithm format.
This tunnel is using aggressive mode ISAKMP negotiation. The default is main mode. Aggressive mode is less secure than main mode as it reveals your identity to an
eavesdropper, but is needed to support road warriors using PSK keys or to interoperate with other buggy implementations insisting on using aggressive mode.
Pull the Mode Config network information from the peer.
Set the delay (in seconds) between Dead Peer Detection (RFC 3706) keepalives (R_U_THERE, R_U_THERE_ACK) that are sent for this connection (default 30 seconds).
Set the length of time (in seconds) we will idle without hearing either an R_U_THERE poll from our peer, or an R_U_THERE_ACK reply. After this period has elapsed with no
response and no traffic, we will declare the peer dead, and remove the SA (default 120 seconds).
When a DPD enabled peer is declared dead, what action should be taken. hold(default) means the eroute will be put into %hold status, while clearmeans the eroute and SA with
both be cleared. Clear is really only useful on the server of a Road Warrior config. The action restart is used on tunnels that need to be permanently up, and have static IP
addresses. The action restart_by_peerhas been obsoleted and its functionality has been moved into the restart action.
In some cases, for example when ESP packets are filtered or when a broken IPsec peer does not properly recognise NAT, it can be useful to force RFC-3948 encapsulation using
this option. It causes pluto lie and tell the remote peer that RFC-3948 encapsulation (ESP in UDP port 4500 packets) is required.
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 specified.
Apart from initiating directly using the --initiate option, a tunnel can be loaded with a different policy
Only initiate the connection when we have traffic to send over the connection
Allow unencrypted traffic to flow until the tunnel is initiated.
Drop unencrypted traffic silently.
Drop unencrypted traffic silently, but send an ICMP message notifying the other end.
These options need to be documented
to be documented
to be documented
to be documented
to be documented
pluto supports various X.509 Certificate related options.
display all times in UTC.
lists all of the X.509 information known to pluto.
list all the public keys that have been successfully loaded.
list all the X.509 certificates that are currently loaded.
list all the loaded X.509 certificates which are about to expire or have been expired.
list all the Certificate Authority X.509 certificates that are currently loaded.
list all the loaded Certificate Revocation Lists (CRLs)
The corresponding options --rereadsecrets, --rereadall, and --rereadcrls options reread this information from their respective sources, and purge all the online obtained
information. The option --listevents lists all pending CRL fetch commands.
how long pluto will propose that an ISAKMP SA be allowed to live. The default is 3600 (one hour) and the maximum is 86400 (1 day). This option will not affect what is
accepted. pluto will reject proposals that exceed the maximum.
how long pluto will propose that an IPsec SA be allowed to live. The default is 28800 (eight hours) and the maximum is 86400 (one day). This option will not affect what is
accepted. pluto will reject proposals that exceed the maximum.
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).
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.
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
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.
--delete, --name connection-name
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
The deletestate form deletes the state object with the specified serial number. This is useful for selectively deleting instances of connections.
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.
--route, --name connection-name
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.
--unroute, --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 authentication.
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.
--initiate, --name connection-name, --asynchronous
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.
--tunnelipv4, --tunnelipv6, --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.
Ending an connection
--terminate, --name connection-name
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 effect).
If the remote peer has crashed, and therefor did not notify us, we keep sending encrypted traffic, and rejecting all plaintext (non-IKE) traffic from that remote peer. The
--crash brings our end down as well for all the known connections to the specified ip-address
this causes plutoto open the given filename for write, and record each of the messages received from whack or addconn. This continues until the whackstoprecord option is
used. This option may not be combined with any other command. The start/stop commands are not recorded themselves. These files are usually used to create input files for unit
tests, particularly for complex setups where policies may in fact overlap.
The format of the file consists of a line starting with #!pluto-whack and the date that the file was started, as well as the hostname, and a linefeed. What follows are binary
format records consisting of a 32-bit record length in bytes, (including the length record itself), a 64-bit timestamp, and then the literal contents of the whack message
that was received. All integers are in host format. In order to unambigously determine the host order, the first record is an empty record that contains only the current
WHACK_MAGIC value. This record is 16 bytes long.
If the remote peer has crashed, and therefor did not notify us, we keep sending encrypted traffic, and rejecting all plaintext (non-IKE) traffic from that remote peer. The
--crash brings our end down as well for all the known connections to the specified ip-address
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 ipsec.secrets(5).
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
specifies that the new key is added to the collection; otherwise the new key replaces any old ones.
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 0s.
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 busy and relax options tells pluto to explicitly activate or deactivate additional DDoS protection. Normally, these meassures are automatically activate or deactivate based
on the number of states inside pluto. One of these DDoS protection methods is to active IKEv2 DCOOKIEs to defend against spoofed IKE packets.
place pluto into busy mode and activate anti-DDoS measures.
pull pluto out of busy mode and deactivate anti-DDoS measures.
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 trafficstatus form will display the xauth username, add_time and the total in and out bytes of the IPsec SA's.
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
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
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 127.0.0.1 --to --host 127.0.0.2 --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 conn_name --host 10.0.0.1 --client 10.0.1.0/24 --to --host 10.0.0.2 --client 10.0.2.0/24 --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 conn_name
Finally, we are ready to get pluto to initiate negotiation for an IPsec SA (and implicitly, an ISAKMP SA):
ipsec whack --initiate --name conn_name
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
If pluto needs additional authentication, such as defined by the XAUTH specifications, then it may ask whack to prompt the operator for username or passwords. Typically, these
will be entered interactively. A GUI that wraps around whack may look for the 041 (username) or 040 (password) prompts, and display them to the user.
For testing purposes, the options --xauthuser user--xauthpass pass may be be given prior to the --initiate to provide responses to the username and password prompts.
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 sent.
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 255.255.255.255.
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
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 255.255.255.255.
lists the protocols allowed over this IPsec SA.
lists the protocols the peer allows over this IPsec SA.
lists the ports allowed over this IPsec SA.
lists the ports the peer allows over this IPsec SA.
lists our id.
Dlists our peer's id.
lists the peer's CA.
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 negotiation.
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
When pluto is responding to a