STRONGSWAN.CONF(5) strongSwan STRONGSWAN.CONF(5)
NAME
strongswan.conf - strongSwan configuration file
DESCRIPTION
While the ipsec.conf(5) configuration file is well suited to define IPsec related configuration parameters, it is not useful for other
strongSwan applications to read options from this file. The file is hard to parse and only ipsec starter is capable of doing so. As the
number of components of the strongSwan project is continually growing, a more flexible configuration file was needed, one that is easy to
extend and can be used by all components. With strongSwan 4.2.1 strongswan.conf(5) was introduced which meets these requirements.
SYNTAX
The format of the strongswan.conf file consists of hierarchical sections and a list of key/value pairs in each section. Each section has a
name, followed by C-Style curly brackets defining the section body. Each section body contains a set of subsections and key/value pairs:
settings := (section|keyvalue)*
section := name { settings }
keyvalue := key = value
Values must be terminated by a newline.
Comments are possible using the #-character, but be careful: The parser implementation is currently limited and does not like brackets in
comments.
Section names and keys may contain any printable character except:
. { } #
space
An example file in this format might look like this:
a = b
section-one {
somevalue = asdf
subsection {
othervalue = xxx
}
# yei, a comment
yetanother = zz
}
section-two {
x = 12
}
Indentation is optional, you may use tabs or spaces.
INCLUDING FILES
Using the include statement it is possible to include other files into strongswan.conf, e.g.
include /some/path/*.conf
If the file name is not an absolute path, it is considered to be relative to the directory of the file containing the include statement.
The file name may include shell wildcards (see sh(1)). Also, such inclusions can be nested.
Sections loaded from included files extend previously loaded sections; already existing values are replaced. It is important to note that
settings are added relative to the section the include statement is in.
As an example, the following three files result in the same final config as the one given above:
a = b
section-one {
somevalue = before include
include include.conf
}
include other.conf
include.conf:
# settings loaded from this file are added to section-one
# the following replaces the previous value
somevalue = asdf
subsection {
othervalue = yyy
}
yetanother = zz
other.conf:
# this extends section-one and subsection
section-one {
subsection {
# this replaces the previous value
othervalue = xxx
}
}
section-two {
x = 12
}
READING VALUES
Values are accessed using a dot-separated section list and a key. With reference to the example above, accessing section-one.subsec-
tion.othervalue will return xxx.
DEFINED KEYS
The following keys are currently defined (using dot notation). The default value (if any) is listed in brackets after the key.
charon section
charon.block_threshold [5]
Maximum number of half-open IKE_SAs for a single peer IP
charon.close_ike_on_child_failure [no]
Close the IKE_SA if setup of the CHILD_SA along with IKE_AUTH failed
charon.cookie_threshold [10]
Number of half-open IKE_SAs that activate the cookie mechanism
charon.dns1
charon.dns2
DNS servers assigned to peer via configuration payload (CP)
charon.dos_protection [yes]
Enable Denial of Service protection using cookies and aggressiveness checks
charon.filelog
Section to define file loggers, see LOGGER CONFIGURATION
charon.flush_auth_cfg [no]
charon.hash_and_url [no]
Enable hash and URL support
charon.ignore_routing_tables
A list of routing tables to be excluded from route lookup
charon.ikesa_table_segments [1]
Number of exclusively locked segments in the hash table
charon.ikesa_table_size [1]
Size of the IKE_SA hash table
charon.inactivity_close_ike [no]
Whether to close IKE_SA if the only CHILD_SA closed due to inactivity
charon.install_routes [yes]
Install routes into a separate routing table for established IPsec tunnels
charon.install_virtual_ip [yes]
Install virtual IP addresses
charon.keep_alive [20s]
NAT keep alive interval
charon.load
Plugins to load in the IKEv2 daemon charon
charon.max_packet [10000]
Maximum packet size accepted by charon
charon.multiple_authentication [yes]
Enable multiple authentication exchanges (RFC 4739)
charon.nbns1
charon.nbns2
WINS servers assigned to peer via configuration payload (CP)
charon.process_route [yes]
Process RTM_NEWROUTE and RTM_DELROUTE events
charon.receive_delay [0]
Delay for receiving packets, to simulate larger RTT
charon.receive_delay_response [yes]
Delay response messages
charon.receive_delay_request [yes]
Delay request messages
charon.receive_delay_type [0]
Specific IKEv2 message type to delay, 0 for any
charon.replay_window [32]
Size of the AH/ESP replay window, in packets.
charon.retransmit_base [1.8]
Base to use for calculating exponential back off, see IKEv2 RETRANSMISSION
charon.retransmit_timeout [4.0]
Timeout in seconds before sending first retransmit
charon.retransmit_tries [5]
Number of times to retransmit a packet before giving up
charon.reuse_ikesa [yes]
Initiate CHILD_SA within existing IKE_SAs
charon.routing_table
Numerical routing table to install routes to
charon.routing_table_prio
Priority of the routing table
charon.send_delay [0]
Delay for sending packets, to simulate larger RTT
charon.send_delay_response [yes]
Delay response messages
charon.send_delay_request [yes]
Delay request messages
charon.send_delay_type [0]
Specific IKEv2 message type to delay, 0 for any
charon.send_vendor_id [no]
Send strongSwan vendor ID payload
charon.syslog
Section to define syslog loggers, see LOGGER CONFIGURATION
charon.threads [16]
Number of worker threads in charon
charon.plugins subsection
charon.plugins.android.loglevel [1]
Loglevel for logging to Android specific logger
charon.plugins.attr
Section to specify arbitrary attributes that are assigned to a peer via configuration payload (CP)
charon.plugins.dhcp.identity_lease [no]
Derive user-defined MAC address from hash of IKEv2 identity
charon.plugins.dhcp.server [255.255.255.255]
DHCP server unicast or broadcast IP address
charon.plugins.duplicheck.enable [yes]
enable loaded duplicheck plugin
charon.plugins.eap-aka.request_identity [yes]
charon.plugins.eap-aka-3ggp2.seq_check
charon.plugins.eap-gtc.pam_service [login]
PAM service to be used for authentication
charon.plugins.eap-peap.fragment_size [1024]
Maximum size of an EAP-PEAP packet
charon.plugins.eap-peap.max_message_count [32]
Maximum number of processed EAP-PEAP packets
charon.plugins.eap-peap.include_length [no]
Include length in non-fragmented EAP-PEAP packets
charon.plugins.eap-peap.phase2_method [mschapv2]
Phase2 EAP client authentication method
charon.plugins.eap-peap.phase2_piggyback [no]
Phase2 EAP Identity request piggybacked by server onto TLS Finished message
charon.plugins.eap-peap.phase2_tnc [no]
Start phase2 EAP TNC protocol after successful client authentication
charon.plugins.eap-peap.request_peer_auth [no]
Request peer authentication based on a client certificate
charon.plugins.eap-radius.class_group [no]
Use the class attribute sent in the RADIUS-Accept message as group membership information that is compared to the groups specified
in the rightgroups option in ipsec.conf (5).
charon.plugins.eap-radius.eap_start [no]
Send EAP-Start instead of EAP-Identity to start RADIUS conversation
charon.plugins.eap-radius.filter_id [no]
If the RADIUS tunnel_type attribute with value ESP is received, use the filter_id attribute sent in the RADIUS-Accept message as
group membership information that is compared to the groups specified in the rightgroups option in ipsec.conf (5).
charon.plugins.eap-radius.id_prefix
Prefix to EAP-Identity, some AAA servers use a IMSI prefix to select the EAP method
charon.plugins.eap-radius.nas_identifier [strongSwan]
NAS-Identifier to include in RADIUS messages
charon.plugins.eap-radius.port [1812]
Port of RADIUS server (authentication)
charon.plugins.eap-radius.secret
Shared secret between RADIUS and NAS
charon.plugins.eap-radius.server
IP/Hostname of RADIUS server
charon.plugins.eap-radius.servers
Section to specify multiple RADIUS servers. The nas_identifier, secret, sockets and port options can be specified for each server. A
server's IP/Hostname can be configured using the address option. For each RADIUS server a priority can be specified using the pref-
erence [0] option.
charon.plugins.eap-radius.sockets [1]
Number of sockets (ports) to use, increase for high load
charon.plugins.eap-sim.request_identity [yes]
charon.plugins.eap-simaka-sql.database
charon.plugins.eap-simaka-sql.remove_used
charon.plugins.eap-tls.fragment_size [1024]
Maximum size of an EAP-TLS packet
charon.plugins.eap-tls.max_message_count [32]
Maximum number of processed EAP-TLS packets
charon.plugins.eap-tls.include_length [yes]
Include length in non-fragmented EAP-TLS packets
charon.plugins.eap-tnc.fragment_size [50000]
Maximum size of an EAP-TNC packet
charon.plugins.eap-tnc.max_message_count [10]
Maximum number of processed EAP-TNC packets
charon.plugins.eap-tnc.include_length [yes]
Include length in non-fragmented EAP-TNC packets
charon.plugins.eap-ttls.fragment_size [1024]
Maximum size of an EAP-TTLS packet
charon.plugins.eap-ttls.max_message_count [32]
Maximum number of processed EAP-TTLS packets
charon.plugins.eap-ttls.include_length [yes]
Include length in non-fragmented EAP-TTLS packets
charon.plugins.eap-ttls.phase2_method [md5]
Phase2 EAP client authentication method
charon.plugins.eap-ttls.phase2_piggyback [no]
Phase2 EAP Identity request piggybacked by server onto TLS Finished message
charon.plugins.eap-ttls.phase2_tnc [no]
Start phase2 EAP TNC protocol after successful client authentication
charon.plugins.eap-ttls.request_peer_auth [no]
Request peer authentication based on a client certificate
charon.plugins.ha.fifo_interface [yes]
charon.plugins.ha.heartbeat_delay [1000]
charon.plugins.ha.heartbeat_timeout [2100]
charon.plugins.ha.local
charon.plugins.ha.monitor [yes]
charon.plugins.ha.pools
charon.plugins.ha.remote
charon.plugins.ha.resync [yes]
charon.plugins.ha.secret
charon.plugins.ha.segment_count [1]
charon.plugins.led.activity_led
charon.plugins.led.blink_time [50]
charon.plugins.kernel-klips.ipsec_dev_count [4]
Number of ipsecN devices
charon.plugins.kernel-klips.ipsec_dev_mtu [0]
Set MTU of ipsecN device
charon.plugins.load-tester
Section to configure the load-tester plugin, see LOAD TESTS
charon.plugins.resolve.file [/etc/resolv.conf]
File where to add DNS server entries
charon.plugins.sql.database
Database URI for charons SQL plugin
charon.plugins.sql.loglevel [-1]
Loglevel for logging to SQL database
charon.plugins.tnc-imc.preferred_language [en]
Preferred language for TNC recommendations
charon.plugins.tnc-imc.tnc_config [/etc/tnc_config]
TNC IMC configuration directory
charon.plugins.tnc-imv.tnc_config [/etc/tnc_config]
TNC IMV configuration directory
charon.plugins.whitelist.enable [yes]
enable loaded whitelist plugin
libstrongswan section
libstrongswan.crypto_test.bench [no]
libstrongswan.crypto_test.bench_size [1024]
libstrongswan.crypto_test.bench_time [50]
libstrongswan.crypto_test.on_add [no]
Test crypto algorithms during registration
libstrongswan.crypto_test.on_create [no]
Test crypto algorithms on each crypto primitive instantiation
libstrongswan.crypto_test.required [no]
Strictly require at least one test vector to enable an algorithm
libstrongswan.crypto_test.rng_true [no]
Whether to test RNG with TRUE quality; requires a lot of entropy
libstrongswan.dh_exponent_ansi_x9_42 [yes]
Use ANSI X9.42 DH exponent size or optimum size matched to cryptographical strength
libstrongswan.ecp_x_coordinate_only [yes]
Compliance with the errata for RFC 4753
libstrongswan.integrity_test [no]
Check daemon, libstrongswan and plugin integrity at startup
libstrongswan.leak_detective.detailed [yes]
Includes source file names and line numbers in leak detective output
libstrongswan.x509.enforce_critical [yes]
Discard certificates with unsupported or unknown critical extensions
libstrongswan.plugins subsection
libstrongswan.plugins.attr-sql.database
Database URI for attr-sql plugin used by charon and pluto
libstrongswan.plugins.attr-sql.lease_history [yes]
Enable logging of SQL IP pool leases
libstrongswan.plugins.gcrypt.quick_random [no]
Use faster random numbers in gcrypt; for testing only, produces weak keys!
libstrongswan.plugins.openssl.engine_id [pkcs11]
ENGINE ID to use in the OpenSSL plugin
libstrongswan.plugins.pkcs11.modules
libstrongswan.plugins.pkcs11.use_hasher [no]
libtls section
libtls.cipher
List of TLS encryption ciphers
libtls.key_exchange
List of TLS key exchange methods
libtls.mac
List of TLS MAC algorithms
libtls.suites
List of TLS cipher suites
manager section
manager.database
Credential database URI for manager
manager.debug [no]
Enable debugging in manager
manager.load
Plugins to load in manager
manager.socket
FastCGI socket of manager, to run it statically
manager.threads [10]
Threads to use for request handling
manager.timeout [15m]
Session timeout for manager
mediation client section
medcli.database
Mediation client database URI
medcli.dpd [5m]
DPD timeout to use in mediation client plugin
medcli.rekey [20m]
Rekeying time on mediation connections in mediation client plugin
mediation server section
medsrv.database
Mediation server database URI
medsrv.debug [no]
Debugging in mediation server web application
medsrv.dpd [5m]
DPD timeout to use in mediation server plugin
medsrv.load
Plugins to load in mediation server plugin
medsrv.password_length [6]
Minimum password length required for mediation server user accounts
medsrv.rekey [20m]
Rekeying time on mediation connections in mediation server plugin
medsrv.socket
Run Mediation server web application statically on socket
medsrv.threads [5]
Number of thread for mediation service web application
medsrv.timeout [15m]
Session timeout for mediation service
openac section
openac.load
Plugins to load in ipsec openac tool
pki section
pki.load
Plugins to load in ipsec pki tool
pluto section
pluto.dns1
pluto.dns2
DNS servers assigned to peer via Mode Config
pluto.load
Plugins to load in IKEv1 pluto daemon
pluto.nbns1
pluto.nbns2
WINS servers assigned to peer via Mode Config
pluto.threads [4]
Number of worker threads in pluto
pluto.plugins section
pluto.plugins.attr
Section to specify arbitrary attributes that are assigned to a peer via Mode Config
charon.plugins.kernel-klips.ipsec_dev_count [4]
Number of ipsecN devices
charon.plugins.kernel-klips.ipsec_dev_mtu [0]
Set MTU of ipsecN device
pool section
pool.load
Plugins to load in ipsec pool tool
scepclient section
scepclient.load
Plugins to load in ipsec scepclient tool
starter section
starter.load_warning [yes]
Disable charon/pluto plugin load option warning
LOGGER CONFIGURATION
The options described below provide a much more flexible way to configure loggers for the IKEv2 daemon charon than using the charondebug
option in ipsec.conf(5).
Please note that if any loggers are specified in strongswan.conf, charondebug does not have any effect.
There are currently two types of loggers defined:
File loggers
Log directly to a file and are defined by specifying the full path to the file as subsection in the charon.filelog section. To log
to the console the two special filenames stdout and stderr can be used.
Syslog loggers
Log into a syslog facility and are defined by specifying the facility to log to as the name of a subsection in the charon.syslog
section. The following facilities are currently supported: daemon and auth.
Multiple loggers can be defined for each type with different log verbosity for the different subsystems of the daemon.
Options
charon.filelog.<filename>.default [1]
charon.syslog.<facility>.default
Specifies the default loglevel to be used for subsystems for which no specific loglevel is defined.
charon.filelog.<filename>.<subsystem> [<default>]
charon.syslog.<facility>.<subsystem>
Specifies the loglevel for the given subsystem.
charon.filelog.<filename>.append [yes]
If this option is enabled log entries are appended to the existing file.
charon.filelog.<filename>.flush_line [no]
Enabling this option disables block buffering and enables line buffering.
charon.filelog.<filename>.ike_name [no]
charon.syslog.<facility>.ike_name
Prefix each log entry with the connection name and a unique numerical identifier for each IKE_SA.
charon.filelog.<filename>.time_format
Prefix each log entry with a timestamp. The option accepts a format string as passed to strftime(3).
Subsystems
dmn Main daemon setup/cleanup/signal handling
mgr IKE_SA manager, handling synchronization for IKE_SA access
ike IKE_SA
chd CHILD_SA
job Jobs queueing/processing and thread pool management
cfg Configuration management and plugins
knl IPsec/Networking kernel interface
net IKE network communication
enc Packet encoding/decoding encryption/decryption operations
tls libtls library messages
lib libstrongwan library messages
Loglevels
-1 Absolutely silent
0 Very basic auditing logs, (e.g. SA up/SA down)
1 Generic control flow with errors, a good default to see whats going on
2 More detailed debugging control flow
3 Including RAW data dumps in Hex
4 Also include sensitive material in dumps, e.g. keys
Example
charon {
filelog {
/var/log/charon.log {
time_format = %b %e %T
append = no
default = 1
}
stderr {
ike = 2
knl = 3
ike_name = yes
}
}
syslog {
# enable logging to LOG_DAEMON, use defaults
daemon {
}
# minimalistic IKE auditing logging to LOG_AUTHPRIV
auth {
default = -1
ike = 0
}
}
}
LOAD TESTS
To do stability testing and performance optimizations, the IKEv2 daemon charon provides the load-tester plugin. This plugin allows to setup
thousands of tunnels concurrently against the daemon itself or a remote host.
WARNING: Never enable the load-testing plugin on productive systems. It provides preconfigured credentials and allows an attacker to
authenticate as any user.
Options
charon.plugins.load-tester.child_rekey [600]
Seconds to start CHILD_SA rekeying after setup
charon.plugins.load-tester.delay [0]
Delay between initiatons for each thread
charon.plugins.load-tester.delete_after_established [no]
Delete an IKE_SA as soon as it has been established
charon.plugins.load-tester.dynamic_port [0]
Base port to be used for requests (each client uses a different port)
charon.plugins.load-tester.enable [no]
Enable the load testing plugin
charon.plugins.load-tester.fake_kernel [no]
Fake the kernel interface to allow load-testing against self
charon.plugins.load-tester.ike_rekey [0]
Seconds to start IKE_SA rekeying after setup
charon.plugins.load-tester.initiators [0]
Number of concurrent initiator threads to use in load test
charon.plugins.load-tester.initiator_auth [pubkey]
Authentication method(s) the intiator uses
charon.plugins.load-tester.iterations [1]
Number of IKE_SAs to initate by each initiator in load test
charon.plugins.load-tester.pool
Provide INTERNAL_IPV4_ADDRs from a named pool
charon.plugins.load-tester.proposal [aes128-sha1-modp768]
IKE proposal to use in load test
charon.plugins.load-tester.remote [127.0.0.1]
Address to initiation connections to
charon.plugins.load-tester.responder_auth [pubkey]
Authentication method(s) the responder uses
charon.plugins.load-tester.request_virtual_ip [no]
Request an INTERNAL_IPV4_ADDR from the server
charon.plugins.load-tester.shutdown_when_complete [no]
Shutdown the daemon after all IKE_SAs have been established
Configuration details
For public key authentication, the responder uses the "CN=srv, OU=load-test, O=strongSwan" identity. For the initiator, each connection
attempt uses a different identity in the form "CN=c1-r1, OU=load-test, O=strongSwan", where the first number inidicates the client number,
the second the authentication round (if multiple authentication is used).
For PSK authentication, FQDN identities are used. The server uses srv.strongswan.org, the client uses an identity in the form
c1-r1.strongswan.org.
For EAP authentication, the client uses a NAI in the form 100000000010001@strongswan.org.
To configure multiple authentication, concatenate multiple methods using, e.g.
initiator_auth = pubkey|psk|eap-md5|eap-aka
The responder uses a hardcoded certificate based on a 1024-bit RSA key. This certificate additionally serves as CA certificate. A peer
uses the same private key, but generates client certificates on demand signed by the CA certificate. Install the Responder/CA certificate
on the remote host to authenticate all clients.
To speed up testing, the load tester plugin implements a special Diffie-Hellman implementation called modpnull. By setting
proposal = aes128-sha1-modpnull
this wicked fast DH implementation is used. It does not provide any security at all, but allows to run tests without DH calculation over-
head.
Examples
In the simplest case, the daemon initiates IKE_SAs against itself using the loopback interface. This will actually establish double the
number of IKE_SAs, as the daemon is initiator and responder for each IKE_SA at the same time. Installation of IPsec SAs would fails, as
each SA gets installed twice. To simulate the correct behavior, a fake kernel interface can be enabled which does not install the IPsec SAs
at the kernel level.
A simple loopback configuration might look like this:
charon {
# create new IKE_SAs for each CHILD_SA to simulate
# different clients
reuse_ikesa = no
# turn off denial of service protection
dos_protection = no
plugins {
load-tester {
# enable the plugin
enable = yes
# use 4 threads to initiate connections
# simultaneously
initiators = 4
# each thread initiates 1000 connections
iterations = 1000
# delay each initiation in each thread by 20ms
delay = 20
# enable the fake kernel interface to
# avoid SA conflicts
fake_kernel = yes
}
}
}
This will initiate 4000 IKE_SAs within 20 seconds. You may increase the delay value if your box can not handle that much load, or decrease
it to put more load on it. If the daemon starts retransmitting messages your box probably can not handle all connection attempts.
The plugin also allows to test against a remote host. This might help to test against a real world configuration. A connection setup to do
stress testing of a gateway might look like this:
charon {
reuse_ikesa = no
threads = 32
plugins {
load-tester {
enable = yes
# 10000 connections, ten in parallel
initiators = 10
iterations = 1000
# use a delay of 100ms, overall time is:
# iterations * delay = 100s
delay = 100
# address of the gateway
remote = 1.2.3.4
# IKE-proposal to use
proposal = aes128-sha1-modp1024
# use faster PSK authentication instead
# of 1024bit RSA
initiator_auth = psk
responder_auth = psk
# request a virtual IP using configuration
# payloads
request_virtual_ip = yes
# enable CHILD_SA every 60s
child_rekey = 60
}
}
}
IKEv2 RETRANSMISSION
Retransmission timeouts in the IKEv2 daemon charon can be configured globally using the three keys listed below:
charon.retransmit_base [1.8]
charon.retransmit_timeout [4.0]
charon.retransmit_tries [5]
The following algorithm is used to calculate the timeout:
relative timeout = retransmit_timeout * retransmit_base ^ (n-1)
Where n is the current retransmission count.
Using the default values, packets are retransmitted in:
Retransmission Relative Timeout Absolute Timeout
-----------------------------------------------------
1 4s 4s
2 7s 11s
3 13s 24s
4 23s 47s
5 42s 89s
giving up 76s 165s
FILES
/etc/strongswan.conf
SEE ALSO
ipsec.conf(5), ipsec.secrets(5), ipsec(8)
HISTORY
Written for the strongSwan project <http://www.strongswan.org> by Tobias Brunner, Andreas Steffen and Martin Willi.
4.5.2 2010-09-09 STRONGSWAN.CONF(5)