strongswan.conf¶

Overview¶

While the ipsec.conf 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, we needed a more flexible configuration file that is easy to extend and can be used by all components. The new configuration format consists of hierarchical sections and a list of key/value pairs in each section. Starting with the strongSwan 4.2.1 release, a default strongswan.conf file is installed in your sysconfdir, e.g. /etc/strongswan.conf.

Syntax¶

Each section has a name, followed by C-Style curly brackets defining the sections body. Each section body contains a set of subsections and key/value pairs:

settings := (section|keyvalue)*
section  := name { settings }
keyvalue := key = value\n

Values must be terminated by a newline. Comments are possible using the #-character, but be careful: The parser implementation is currently limited and does not like braces in comments. Section names and keys may contain any printable character except:

. { } # \n \t space

An example 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¶

Version 4.5.1 introduced the include statement which allows 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. Also, such inclusions can be nested.

Sections loaded from the 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¶

The config file is read by libstrongswan during library initialization. Values are accessed using a dot-separated section list and a key:
Accessing section-one.subsection.othervalue will return xxx.

Have a look at the settings interface (source:src/libstrongswan/settings.h) to learn about the details.

Defined keys¶

The following keys are currently defined (using dot notation).

Key	Default	Description
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		DNS server 1 assigned to peer via configuration payload (CP), see attr plugin
charon.dns2		DNS server 2 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 LoggerConfiguration
charon.flush_auth_cfg	no
charon.half_open_timeout	30	Timeout in seconds for connecting IKE_SAs, also see IKE_SA_INIT dropping
charon.hash_and_url	no	Enable hash and URL support
charon.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.init_limit_half_open	0	Limit new connections based on the current number of half open IKE_SAs, see IKE_SA_INIT dropping
charon.init_limit_job_load	0	Limit new connections based on the number of jobs currently queued for processing, see IKE_SA_INIT dropping
charon.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 IKEv2 charon daemon, see PluginLoad
charon.max_packet	10000	Maximum packet size accepted by charon
charon.multiple_authentication	yes	Enable multiple authentication exchanges (RFC 4739)
charon.nbns1		WINS server 1 assigned to peer via configuration payload (CP), see attr plugin
charon.nbns2		WINS server 2 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.retransmit_base	1.8	Base to use for calculating exponential back off, see 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 LoggerConfiguration
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, see attr plugin
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, see DHCP plugin
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, see EAP-GTC
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.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, see EapRadius
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	Use the filter_id attribute sent in the RADIUS-Accept message as group membership if the RADIUS tunnel_type attribute is set to ESP
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, see EapRadius
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-TM NC 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.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.dpd_delay	0	DPD delay to use in load test
charon.plugins.load-tester.dynamic_port	0	Base port to be used for requests (each client uses a different port)
charon.plugins.load-tester.eap_password	default-pwd	EAP secret to use in load test
charon.plugins.load-tester.enable	no	Enable the load testing plugin. Read LoadTests first!
charon.plugins.load-tester.fake_kernel	no	Fake the kernel interface to allow load-testing against self
charon.plugins.load-tester.ike_rekey	0	Seconds to start IKE_SA rekeying after setup
charon.plugins.load-tester.init_limit	0	Global limit of concurrently established SAs during load test
charon.plugins.load-tester.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.initiator_id		Initiator ID to use in load test
charon.plugins.load-tester.iterations	1	Number of IKE_SAs to initate to self by each initiator in load test
charon.plugins.load-tester.pool		Provide INTERNAL_IPV4_ADDRs from a named pool
charon.plugins.load-tester.preshared_key	default-psk	Preshared key to use in load test
charon.plugins.load-tester.proposal	aes128-sha1-modp768	IKE proposal to use in load test
charon.plugins.load-tester.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.responder_id		Responder ID to use in load test
charon.plugins.load-tester.request_virtual_ip	no	Request an INTERNAL_IPV4_ADDR from the server
charon.plugins.load-tester.shutdown_when_complete	no	Shutdown the daemon after all IKE_SAs have been established
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_imv.tnc_config	/etc/tnc_config	TNC IMC configuration directory
charon.plugins.tnc_imc.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.processor.priority_threads		Subsection to configure the number of reserved threads per priority class (see JobPriority)
libstrongswan.x509.enforce_critical	yes	Discard certificates with unsupported or unknown critical extensions
libstrongswan plugins subsection
libstrongswan.plugins.attr-sql.database		Database URI for the 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		List of available PKCS#11 modules, see SmartCardsIKEv2
libstrongswan.plugins.pkcs11.use_hasher	no	Whether the PKCS#11 modules should be used to hash data
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
libimcv section
libimcv.debug_level	1	Debug level for a standalone libimcv library
libimcv.stderr_quiet	no	Disable the output to stderr in a standalone libimcv library
libimcv plugins subsection
libimcv.plugins.imc_test.command	none	Command to be sent to the IMV Test
libimcv.plugins.imc_test.retry	no	Do a handshake retry
libimcv.plugins.imc_test.retry_command		Command to be sent to the IMV Test in the handshake retry
libimcv.plugins.imv_test.rounds	0	Number of IMC-IMV retry rounds
libimcv.plugins.imv_scanner.closed_port_policy	yes	By default all ports must be closed (yes) or can be open (no)
libimcv.plugins.imv_scanner.tcp_ports		List of TCP ports that can be open or must be closed
libimcv.plugins.imv_scanner.udp_ports		List of UDP ports that can be open or must be closed
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		DNS server 1 assigned to peer via Mode Config, see attr plugin
pluto.dns2		DNS server 2 assigned to peer via Mode Config
pluto.load		Plugins to load in IKEv1 pluto daemon, also see PluginLoad
pluto.nbns1		WINS server 1 assigned to peer via Mode Config, see attr plugin
pluto.nbns2		WINS server 2 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, see attr plugin
pluto.plugins.kernel-klips.ipsec_dev_count	4	Number of ipsecN devices
pluto.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