STRONGSWAN.CONF(5) strongSwan STRONGSWAN.CONF(5)NAMEstrongswan.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 sec‐
tions 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\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 brackets in com‐
ments.
Section names and keys may contain any printable character except:
. { } # \n \t 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 rela‐
tive to the directory of the file containing the include statement. The
file name may include shell wildcards (see sh(1)). Also, such inclu‐
sions 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 con‐
fig 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.subsection.other‐
value 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.
attest.database []
File measurement information database URI. If it contains a
password, make sure to adjust the permissions of the config file
accordingly.
attest.load []
Plugins to load in ipsec attest tool.
charon
Options for the charon IKE daemon.
Note: Many of the options in this section also apply to
charon-cmd and other charon derivatives. Just use their respec‐
tive name (e.g. charon-cmd instead of charon). For many
options defaults can be defined in the libstrongswan section.
charon.block_threshold [5]
Maximum number of half-open IKE_SAs for a single peer IP.
charon.cert_cache [yes]
Whether relations in validated certificate chains should be
cached in memory.
charon.cisco_unity [no]
Send Cisco Unity vendor ID payload (IKEv1 only).
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.crypto_test.bench [no]
Benchmark crypto algorithms and order them by efficiency.
charon.crypto_test.bench_size [1024]
Buffer size used for crypto benchmark.
charon.crypto_test.bench_time [50]
Number of iterations to test each algorithm.
charon.crypto_test.on_add [no]
Test crypto algorithms during registration (requires test vec‐
tors provided by the test-vectors plugin).
charon.crypto_test.on_create [no]
Test crypto algorithms on each crypto primitive instantiation.
charon.crypto_test.required [no]
Strictly require at least one test vector to enable an algo‐
rithm.
charon.crypto_test.rng_true [no]
Whether to test RNG with TRUE quality; requires a lot of
entropy.
charon.dh_exponent_ansi_x9_42 [yes]
Use ANSI X9.42 DH exponent size or optimum size matched to cryp‐
tographic strength.
charon.dns1 []
DNS server assigned to peer via configuration payload (CP).
charon.dns2 []
DNS server assigned to peer via configuration payload (CP).
charon.dos_protection [yes]
Enable Denial of Service protection using cookies and aggres‐
siveness checks.
charon.ecp_x_coordinate_only [yes]
Compliance with the errata for RFC 4753.
charon.filelog
Section to define file loggers, see LOGGER CONFIGURATION in
strongswan.conf(5).
charon.filelog.<filename>
<filename> is the full path to the log file.
charon.filelog.<filename>.<subsystem> [<default>]
Loglevel for a specific subsystem.
charon.filelog.<filename>.append [yes]
If this option is enabled log entries are appended to the exist‐
ing file.
charon.filelog.<filename>.default [1]
Specifies the default loglevel to be used for subsystems for
which no specific loglevel is defined.
charon.filelog.<filename>.flush_line [no]
Enabling this option disables block buffering and enables line
buffering.
charon.filelog.<filename>.ike_name [no]
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).
charon.flush_auth_cfg [no]
If enabled objects used during authentication (certificates,
identities etc.) are released to free memory once an IKE_SA is
established. Enabling this might conflict with plugins that
later need access to e.g. the used certificates.
charon.fragment_size [512]
Maximum size (in bytes) of a sent fragment when using the pro‐
prietary IKEv1 fragmentation extension.
charon.group []
Name of the group the daemon changes to after startup.
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.host_resolver.max_threads [3]
Maximum number of concurrent resolver threads (they are termi‐
nated if unused).
charon.host_resolver.min_threads [0]
Minimum number of resolver threads to keep around.
charon.i_dont_care_about_security_and_use_aggressive_mode_psk [no]
If enabled responders are allowed to use IKEv1 Aggressive Mode
with pre-shared keys, which is discouraged due to security con‐
cerns (offline attacks on the openly transmitted hash of the
PSK).
charon.ignore_routing_tables []
A space-separated list of routing tables to be excluded from
route lookups.
charon.ikesa_limit [0]
Maximum number of IKE_SAs that can be established at the same
time before new connection attempts are blocked.
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.imcv
Defaults for options in this section can be configured in the
libimcv section.
charon.imcv.assessment_result [yes]
Whether IMVs send a standard IETF Assessment Result attribute.
charon.imcv.database []
Global IMV policy database URI. If it contains a password, make
sure to adjust the permissions of the config file accordingly.
charon.imcv.os_info.name []
Manually set the name of the client OS (e.g. Ubuntu).
charon.imcv.os_info.version []
Manually set the version of the client OS (e.g. 12.04 i686).
charon.imcv.policy_script [ipsec _imv_policy]
Script called for each TNC connection to generate IMV policies.
charon.inactivity_close_ike [no]
Whether to close IKE_SA if the only CHILD_SA closed due to inac‐
tivity.
charon.init_limit_half_open [0]
Limit new connections based on the current number of half open
IKE_SAs, see IKE_SA_INIT DROPPING in strongswan.conf(5).
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.initiator_only [no]
Causes charon daemon to ignore IKE initiation requests.
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.install_virtual_ip_on []
The name of the interface on which virtual IP addresses should
be installed. If not specified the addresses will be installed
on the outbound interface.
charon.integrity_test [no]
Check daemon, libstrongswan and plugin integrity at startup.
charon.interfaces_ignore []
A comma-separated list of network interfaces that should be
ignored, if interfaces_use is specified this option has no
effect.
charon.interfaces_use []
A comma-separated list of network interfaces that should be used
by charon. All other interfaces are ignored.
charon.keep_alive [20s]
NAT keep alive interval.
charon.leak_detective.detailed [yes]
Includes source file names and line numbers in leak detective
output.
charon.leak_detective.usage_threshold [10240]
Threshold in bytes for leaks to be reported (0 to report all).
charon.leak_detective.usage_threshold_count [0]
Threshold in number of allocations for leaks to be reported (0
to report all).
charon.load []
Plugins to load in the IKE daemon charon.
charon.load_modular [no]
If enabled, the list of plugins to load is determined via the
value of the charon.plugins.<name>.load options. In addition to
a simple boolean flag that option may take an integer value
indicating the priority of a plugin, which would influence the
order of a plugin in the plugin list (the default is 1). If two
plugins have the same priority their order in the default plugin
list is preserved. Enabled plugins not found in that list are
ordered alphabetically before other plugins with the same prior‐
ity.
charon.max_packet [10000]
Maximum packet size accepted by charon.
charon.multiple_authentication [yes]
Enable multiple authentication exchanges (RFC 4739).
charon.nbns1 []
WINS servers assigned to peer via configuration payload (CP).
charon.nbns2 []
WINS servers assigned to peer via configuration payload (CP).
charon.plugins.android_log.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.attr.<attr> []
<attr> can be either address, netmask, dns, nbns, dhcp, subnet,
split-include, split-exclude or the numeric identifier of the
attribute type. The assigned value can be an IPv4/IPv6 address,
a subnet in CIDR notation or an arbitrary value depending on the
attribute type. For some attribute types multiple values may be
specified as a comma separated list.
charon.plugins.attr-sql.database []
Database URI for attr-sql plugin used by charon. If it contains
a password, make sure to adjust the permissions of the config
file accordingly.
charon.plugins.attr-sql.lease_history [yes]
Enable logging of SQL IP pool leases.
charon.plugins.certexpire.csv.cron []
Cron style string specifying CSV export times.
charon.plugins.certexpire.csv.empty_string []
String to use in empty intermediate CA fields.
charon.plugins.certexpire.csv.fixed_fields [yes]
Use a fixed intermediate CA field count.
charon.plugins.certexpire.csv.force [yes]
Force export of all trustchains we have a private key for.
charon.plugins.certexpire.csv.format [%d:%m:%Y]
strftime(3) format string to export expiration dates as.
charon.plugins.certexpire.csv.local []
strftime(3) format string for the CSV file name to export local
certificates to.
charon.plugins.certexpire.csv.remote []
strftime(3) format string for the CSV file name to export remote
certificates to.
charon.plugins.certexpire.csv.separator [,]
CSV field separator.
charon.plugins.coupling.file []
File to store coupling list to.
charon.plugins.coupling.hash [sha1]
Hashing algorithm to fingerprint coupled certificates.
charon.plugins.coupling.max [1]
Maximum number of coupling entries to create.
charon.plugins.dhcp.force_server_address [no]
Always use the configured server address. This might be helpful
if the DHCP server runs on the same host as strongSwan, and the
DHCP daemon does not listen on the loopback interface. In that
case the server cannot be reached via unicast (or even
255.255.255.255) as that would be routed via loopback. Setting
this option to yes and configuring the local broadcast address
(e.g. 192.168.0.255) as server address might work.
charon.plugins.dhcp.identity_lease [no]
Derive user-defined MAC address from hash of IKE identity.
charon.plugins.dhcp.interface []
Interface name the plugin uses for address allocation. The
default is to bind to any (0.0.0.0) and let the system decide
which way to route the packets to the DHCP server.
charon.plugins.dhcp.server [255.255.255.255]
DHCP server unicast or broadcast IP address.
charon.plugins.dnscert.enable [no]
Enable fetching of CERT RRs via DNS.
charon.plugins.duplicheck.enable [yes]
Enable duplicheck plugin (if loaded).
charon.plugins.duplicheck.socket [unix://${piddir}/charon.dck]
Socket provided by the duplicheck plugin.
charon.plugins.eap-aka.request_identity [yes]
charon.plugins.eap-aka-3ggp2.seq_check []
charon.plugins.eap-dynamic.prefer_user [no]
If enabled the EAP methods proposed in an EAP-Nak message sent
by the peer are preferred over the methods registered locally.
charon.plugins.eap-dynamic.preferred []
The preferred EAP method(s) to be used. If it is not given the
first registered method will be used initially. If a comma sep‐
arated list is given the methods are tried in the given order
before trying the rest of the registered methods.
charon.plugins.eap-gtc.backend [pam]
XAuth backend to be used for credential verification.
charon.plugins.eap-peap.fragment_size [1024]
Maximum size of an EAP-PEAP packet.
charon.plugins.eap-peap.include_length [no]
Include length in non-fragmented EAP-PEAP packets.
charon.plugins.eap-peap.max_message_count [32]
Maximum number of processed EAP-PEAP packets (0 = no limit).
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 Fin‐
ished message.
charon.plugins.eap-peap.phase2_tnc [no]
Start phase2 EAP TNC protocol after successful client authenti‐
cation.
charon.plugins.eap-peap.request_peer_auth [no]
Request peer authentication based on a client certificate.
charon.plugins.eap-radius.accounting [no]
Send RADIUS accounting information to RADIUS servers.
charon.plugins.eap-radius.accounting_close_on_timeout [yes]
Close the IKE_SA if there is a timeout during interim RADIUS
accounting updates.
charon.plugins.eap-radius.accounting_requires_vip [no]
If enabled, accounting is disabled unless an IKE_SA has at least
one virtual IP.
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.close_all_on_timeout [no]
Closes all IKE_SAs if communication with the RADIUS server times
out. If it is not set only the current IKE_SA is closed.
charon.plugins.eap-radius.dae.enable [no]
Enables support for the Dynamic Authorization Extension (RFC
5176).
charon.plugins.eap-radius.dae.listen [0.0.0.0]
Address to listen for DAE messages from the RADIUS server.
charon.plugins.eap-radius.dae.port [3799]
Port to listen for DAE requests.
charon.plugins.eap-radius.dae.secret []
Shared secret used to verify/sign DAE messages. If set, make
sure to adjust the permissions of the config file accordingly.
charon.plugins.eap-radius.eap_start [no]
Send EAP-Start instead of EAP-Identity to start RADIUS conversa‐
tion.
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.forward.ike_to_radius []
RADIUS attributes to be forwarded from IKEv2 to RADIUS (can be
defined by name or attribute number, a colon can be used to
specify vendor-specific attributes, e.g. Reply-Message, or 11,
or 36906:12).
charon.plugins.eap-radius.forward.radius_to_ike []
Same as charon.plugins.eap-radius.forward.ike_to_radius but from
RADIUS to IKEv2, a strongSwan specific private notify (40969) is
used to transmit the attributes.
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. If set, make sure to
adjust the permissions of the config file accordingly.
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 (or auth_port) options can be specified
for each server. A server's IP/Hostname can be configured using
the address option. The acct_port [1813] option can be used to
specify the port used for RADIUS accounting. For each RADIUS
server a priority can be specified using the preference [0]
option.
charon.plugins.eap-radius.sockets [1]
Number of sockets (ports) to use, increase for high load.
charon.plugins.eap-radius.xauth
Section to configure multiple XAuth authentication rounds via
RADIUS. The subsections define so called authentication profiles
with arbitrary names. In each profile section one or more XAuth
types can be configured, with an assigned message. For each type
a separate XAuth exchange will be initiated and all replies get
concatenated into the User-Password attribute, which then gets
verified over RADIUS.
Available XAuth types are password, passcode, nextpin, and
answer. This type is not relevant to strongSwan or the AAA
server, but the client may show a different dialog (along with
the configured message).
To use the configured profiles, they have to be configured in
the respective connection in ipsec.conf(5) by appending the pro‐
file name, separated by a colon, to the xauth-radius XAauth
backend configuration in rightauth or rightauth2, for instance,
rightauth2=xauth-radius:profile.
charon.plugins.eap-sim.request_identity [yes]
charon.plugins.eap-simaka-sql.database []
charon.plugins.eap-simaka-sql.remove_used [no]
charon.plugins.eap-tls.fragment_size [1024]
Maximum size of an EAP-TLS packet.
charon.plugins.eap-tls.include_length [yes]
Include length in non-fragmented EAP-TLS packets.
charon.plugins.eap-tls.max_message_count [32]
Maximum number of processed EAP-TLS packets (0 = no limit).
charon.plugins.eap-tnc.max_message_count [10]
Maximum number of processed EAP-TNC packets (0 = no limit).
charon.plugins.eap-tnc.protocol [tnccs-1.1]
IF-TNCCS protocol version to be used (tnccs-1.1, tnccs-2.0,
tnccs-dynamic).
charon.plugins.eap-ttls.fragment_size [1024]
Maximum size of an EAP-TTLS packet.
charon.plugins.eap-ttls.include_length [yes]
Include length in non-fragmented EAP-TTLS packets.
charon.plugins.eap-ttls.max_message_count [32]
Maximum number of processed EAP-TTLS packets (0 = no limit).
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 Fin‐
ished message.
charon.plugins.eap-ttls.phase2_tnc [no]
Start phase2 EAP TNC protocol after successful client authenti‐
cation.
charon.plugins.eap-ttls.request_peer_auth [no]
Request peer authentication based on a client certificate.
charon.plugins.error-notify.socket [unix://${piddir}/charon.enfy]
Socket provided by the error-notify plugin.
charon.plugins.gcrypt.quick_random [no]
Use faster random numbers in gcrypt; for testing only, produces
weak keys!
charon.plugins.ha.autobalance [0]
Interval in seconds to automatically balance handled segments
between nodes. Set to 0 to disable.
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.imc-attestation.aik_blob []
AIK encrypted private key blob file.
charon.plugins.imc-attestation.aik_cert []
AIK certificate file.
charon.plugins.imc-attestation.aik_key []
AIK public key file.
charon.plugins.imc-attestation.mandatory_dh_groups [yes]
Enforce mandatory Diffie-Hellman groups.
charon.plugins.imc-attestation.nonce_len [20]
DH nonce length.
charon.plugins.imc-attestation.pcr17_after []
Dummy data if the TBOOT log is not retrieved.
charon.plugins.imc-attestation.pcr17_before []
Dummy data if the TBOOT log is not retrieved.
charon.plugins.imc-attestation.pcr17_meas []
Dummy data if the TBOOT log is not retrieved.
charon.plugins.imc-attestation.pcr18_after []
Dummy data if the TBOOT log is not retrieved.
charon.plugins.imc-attestation.pcr18_before []
Dummy data if the TBOOT log is not retrieved.
charon.plugins.imc-attestation.pcr18_meas []
Dummy data if the TBOOT log is not retrieved.
charon.plugins.imc-attestation.pcr_info [yes]
Whether to send pcr_before and pcr_after info.
charon.plugins.imc-attestation.use_quote2 [yes]
Use Quote2 AIK signature instead of Quote signature.
charon.plugins.imc-os.push_info [yes]
Send operating system info without being prompted.
charon.plugins.imc-scanner.push_info [yes]
Send open listening ports without being prompted.
charon.plugins.imc-swid.swid_directory [${prefix}/share]
Directory where SWID tags are located.
charon.plugins.imc-test.additional_ids [0]
Number of additional IMC IDs.
charon.plugins.imc-test.command [none]
Command to be sent to the Test IMV.
charon.plugins.imc-test.dummy_size [0]
Size of dummy attribute to be sent to the Test IMV (0 = dis‐
abled).
charon.plugins.imc-test.retry [no]
Do a handshake retry.
charon.plugins.imc-test.retry_command []
Command to be sent to the Test IMV in the handshake retry.
charon.plugins.imv-attestation.cadir []
Path to directory with AIK cacerts.
charon.plugins.imv-attestation.dh_group [ecp256]
Preferred Diffie-Hellman group.
charon.plugins.imv-attestation.hash_algorithm [sha256]
Preferred measurement hash algorithm.
charon.plugins.imv-attestation.mandatory_dh_groups [yes]
Enforce mandatory Diffie-Hellman groups.
charon.plugins.imv-attestation.min_nonce_len [0]
DH minimum nonce length.
charon.plugins.imv-os.remediation_uri []
URI pointing to operating system remediation instructions.
charon.plugins.imv-scanner.remediation_uri []
URI pointing to scanner remediation instructions.
charon.plugins.imv-test.rounds [0]
Number of IMC-IMV retry rounds.
charon.plugins.ipseckey.enable [no]
Enable fetching of IPSECKEY RRs via DNS.
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.kernel-libipsec.allow_peer_ts [no]
Allow that the remote traffic selector equals the IKE peer. The
route installed for such traffic (via TUN device) usually pre‐
vents further IKE traffic. The fwmark options for the ker‐
nel-netlink and socket-default plugins can be used to circumvent
that problem.
charon.plugins.kernel-netlink.fwmark []
Firewall mark to set on the routing rule that directs traffic to
our routing table. The format is [!]mark[/mask], where the
optional exclamation mark inverts the meaning (i.e. the rule
only applies to packets that don't match the mark).
charon.plugins.kernel-netlink.roam_events [yes]
Whether to trigger roam events when interfaces, addresses or
routes change.
charon.plugins.kernel-netlink.xfrm_acq_expires [165]
Lifetime of XFRM acquire state in kernel. The value gets written
to /proc/sys/net/core/xfrm_acq_expires. Indirectly controls the
delay of XFRM acquire messages sent.
charon.plugins.kernel-pfroute.vip_wait [1000]
Time in ms to wait until virtual IP addresses appear/disappear
before failing.
charon.plugins.led.activity_led []
charon.plugins.led.blink_time [50]
charon.plugins.load-tester
Section to configure the load-tester plugin, see LOAD TESTS in
strongswan.conf(5) for details.
charon.plugins.load-tester.addrs
Section that contains key/value pairs with address pools (in
CIDR notation) to use for a specific network interface e.g. eth0
= 10.10.0.0/16.
charon.plugins.load-tester.addrs_keep [no]
Whether to keep dynamic addresses even after the associated SA
got terminated.
charon.plugins.load-tester.addrs_prefix [16]
Network prefix length to use when installing dynamic addresses.
If set to -1 the full address is used (i.e. 32 or 128).
charon.plugins.load-tester.ca_dir []
Directory to load (intermediate) CA certificates from.
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.digest [sha1]
Digest algorithm used when issuing certificates.
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. WARNING: Never enable this
plugin on productive systems. It provides preconfigured creden‐
tials and allows an attacker to authenticate as any user.
charon.plugins.load-tester.esp [aes128-sha1]
CHILD_SA proposal to use for load tests.
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.initiator [0.0.0.0]
Address to initiate from.
charon.plugins.load-tester.initiator_auth [pubkey]
Authentication method(s) the intiator uses.
charon.plugins.load-tester.initiator_id []
Initiator ID used in load test.
charon.plugins.load-tester.initiator_match []
Initiator ID to match against as responder.
charon.plugins.load-tester.initiator_tsi []
Traffic selector on initiator side, as proposed by initiator.
charon.plugins.load-tester.initiator_tsr []
Traffic selector on responder side, as proposed by initiator.
charon.plugins.load-tester.initiators [0]
Number of concurrent initiator threads to use in load test.
charon.plugins.load-tester.issuer_cert []
Path to the issuer certificate (if not configured a hard-coded
default value is used).
charon.plugins.load-tester.issuer_key []
Path to private key that is used to issue certificates (if not
configured a hard-coded default value is used).
charon.plugins.load-tester.iterations [1]
Number of IKE_SAs to initiate by each initiator in load test.
charon.plugins.load-tester.mode [tunnel]
IPsec mode to use, one of tunnel, transport, or beet.
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.request_virtual_ip [no]
Request an INTERNAL_IPV4_ADDR from the server.
charon.plugins.load-tester.responder [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 used in load test.
charon.plugins.load-tester.responder_tsi [initiator_tsi]
Traffic selector on initiator side, as narrowed by responder.
charon.plugins.load-tester.responder_tsr [initiator_tsr]
Traffic selector on responder side, as narrowed by responder.
charon.plugins.load-tester.shutdown_when_complete [no]
Shutdown the daemon after all IKE_SAs have been established.
charon.plugins.load-tester.socket [unix://${piddir}/charon.ldt]
Socket provided by the load-tester plugin.
charon.plugins.load-tester.version [0]
IKE version to use (0 means use IKEv2 as initiator and accept
any version as responder).
charon.plugins.lookip.socket [unix://${piddir}/charon.lkp]
Socket provided by the lookip plugin.
charon.plugins.ntru.max_drbg_requests [4294967294]
Number of pseudo-random bit requests from the DRBG before an
automatic reseeding occurs.
charon.plugins.ntru.parameter_set [optimum]
The following parameter sets are available: x9_98_speed,
x9_98_bandwidth, x9_98_balance and optimum, the last set not
being part of the X9.98 standard but having the best perfor‐
mance.
charon.plugins.openssl.engine_id [pkcs11]
ENGINE ID to use in the OpenSSL plugin.
charon.plugins.openssl.fips_mode [0]
Set OpenSSL FIPS mode: disabled(0), enabled(1), Suite B
enabled(2).
charon.plugins.pkcs11.load_certs [yes]
Whether to load certificates from tokens.
charon.plugins.pkcs11.modules
List of available PKCS#11 modules.
charon.plugins.pkcs11.reload_certs [no]
Reload certificates from all tokens if charon receives a SIGHUP.
charon.plugins.pkcs11.use_dh [no]
Whether the PKCS#11 modules should be used for DH and ECDH (see
use_ecc option).
charon.plugins.pkcs11.use_ecc [no]
Whether the PKCS#11 modules should be used for ECDH and ECDSA
public key operations. ECDSA private keys can be used regardless
of this option.
charon.plugins.pkcs11.use_hasher [no]
Whether the PKCS#11 modules should be used to hash data.
charon.plugins.pkcs11.use_pubkey [no]
Whether the PKCS#11 modules should be used for public key opera‐
tions, even for keys not stored on tokens.
charon.plugins.pkcs11.use_rng [no]
Whether the PKCS#11 modules should be used as RNG.
charon.plugins.radattr.dir []
Directory where RADIUS attributes are stored in client-ID spe‐
cific files.
charon.plugins.radattr.message_id [-1]
Attributes are added to all IKE_AUTH messages by default (-1),
or only to the IKE_AUTH message with the given IKEv2 message ID.
charon.plugins.random.random [${random_device}]
File to read random bytes from.
charon.plugins.random.strong_equals_true [no]
If set to yes the RNG_STRONG class reads random bytes from the
same source as the RNG_TRUE class.
charon.plugins.random.urandom [${urandom_device}]
File to read pseudo random bytes from.
charon.plugins.resolve.file [/etc/resolv.conf]
File where to add DNS server entries.
charon.plugins.resolve.resolvconf.iface_prefix [lo.inet.ipsec.]
Prefix used for interface names sent to resolvconf(8). The
nameserver address is appended to this prefix to make it unique.
The result has to be a valid interface name according to the
rules defined by resolvconf. Also, it should have a high prior‐
ity according to the order defined in interface-order(5).
charon.plugins.socket-default.fwmark []
Firewall mark to set on outbound packets.
charon.plugins.socket-default.set_source [yes]
Set source address on outbound packets, if possible.
charon.plugins.socket-default.use_ipv4 [yes]
Listen on IPv4, if possible.
charon.plugins.socket-default.use_ipv6 [yes]
Listen on IPv6, if possible.
charon.plugins.sql.database []
Database URI for charon's SQL plugin. If it contains a password,
make sure to adjust the permissions of the config file accord‐
ingly.
charon.plugins.sql.loglevel [-1]
Loglevel for logging to SQL database.
charon.plugins.stroke.ignore_missing_ca_basic_constraint [no]
Treat certificates in ipsec.d/cacerts and ipsec.conf ca sections
as CA certificates even if they don't contain a CA basic con‐
straint.
charon.plugins.stroke.max_concurrent [4]
Maximum number of stroke messages handled concurrently.
charon.plugins.stroke.prevent_loglevel_changes [no]
If enabled log level changes via stroke socket are not allowed.
charon.plugins.stroke.socket [unix://${piddir}/charon.ctl]
Socket provided by the stroke plugin.
charon.plugins.stroke.timeout [0]
Timeout in ms for any stroke command. Use 0 to disable the time‐
out.
charon.plugins.systime-fix.interval [0]
Interval in seconds to check system time for validity. 0 dis‐
ables the check.
charon.plugins.systime-fix.reauth [no]
Whether to use reauth or delete if an invalid cert lifetime is
detected.
charon.plugins.systime-fix.threshold []
Threshold date where system time is considered valid. Disabled
if not specified.
charon.plugins.systime-fix.threshold_format [%Y]
strptime(3) format used to parse threshold option.
charon.plugins.tnc-ifmap.client_cert []
Path to X.509 certificate file of IF-MAP client.
charon.plugins.tnc-ifmap.client_key []
Path to private key file of IF-MAP client.
charon.plugins.tnc-ifmap.device_name []
Unique name of strongSwan server as a PEP and/or PDP device.
charon.plugins.tnc-ifmap.renew_session_interval [150]
Interval in seconds between periodic IF-MAP RenewSession
requests.
charon.plugins.tnc-ifmap.server_cert []
Path to X.509 certificate file of IF-MAP server.
charon.plugins.tnc-ifmap.server_uri [https://localhost:8444/imap]
URI of the form [https://]servername[:port][/path].
charon.plugins.tnc-ifmap.username_password []
Credentials of IF-MAP client of the form username:password. If
set, make sure to adjust the permissions of the config file
accordingly.
charon.plugins.tnc-imc.dlclose [yes]
Unload IMC after use.
charon.plugins.tnc-imc.preferred_language [en]
Preferred language for TNC recommendations.
charon.plugins.tnc-imv.dlclose [yes]
Unload IMV after use.
charon.plugins.tnc-imv.recommendation_policy [default]
TNC recommendation policy, one of default, any, or all.
charon.plugins.tnc-pdp.pt_tls.enable [yes]
Enable PT-TLS protocol on the strongSwan PDP.
charon.plugins.tnc-pdp.pt_tls.port [271]
PT-TLS server port the strongSwan PDP is listening on.
charon.plugins.tnc-pdp.radius.enable [yes]
Enable RADIUS protocol on the strongSwan PDP.
charon.plugins.tnc-pdp.radius.method [ttls]
EAP tunnel method to be used.
charon.plugins.tnc-pdp.radius.port [1812]
RADIUS server port the strongSwan PDP is listening on.
charon.plugins.tnc-pdp.radius.secret []
Shared RADIUS secret between strongSwan PDP and NAS. If set,
make sure to adjust the permissions of the config file accord‐
ingly.
charon.plugins.tnc-pdp.server []
Name of the strongSwan PDP as contained in the AAA certificate.
charon.plugins.tnc-pdp.timeout []
Timeout in seconds before closing incomplete connections.
charon.plugins.tnccs-11.max_message_size [45000]
Maximum size of a PA-TNC message (XML & Base64 encoding).
charon.plugins.tnccs-20.max_batch_size [65522]
Maximum size of a PB-TNC batch (upper limit via PT-EAP = 65529).
charon.plugins.tnccs-20.max_message_size [65490]
Maximum size of a PA-TNC message (upper limit via PT-EAP =
65497).
charon.plugins.unbound.dlv_anchors []
File to read trusted keys for DLV (DNSSEC Lookaside Validation)
from. It uses the same format as trust_anchors. Only one DLV
can be configured, which is then used as a root trusted DLV,
this means that it is a lookaside for the root.
charon.plugins.unbound.resolv_conf [/etc/resolv.conf]
File to read DNS resolver configuration from.
charon.plugins.unbound.trust_anchors [/etc/ipsec.d/dnssec.keys]
File to read DNSSEC trust anchors from (usually root zone KSK).
The format of the file is the standard DNS Zone file format,
anchors can be stored as DS or DNSKEY entries in the file.
charon.plugins.updown.dns_handler [no]
Whether the updown script should handle DNS servers assigned via
IKEv1 Mode Config or IKEv2 Config Payloads (if enabled they
can't be handled by other plugins, like resolve)
charon.plugins.whitelist.enable [yes]
Enable loaded whitelist plugin.
charon.plugins.whitelist.socket [unix://${piddir}/charon.wlst]
Socket provided by the whitelist plugin.
charon.plugins.xauth-eap.backend [radius]
EAP plugin to be used as backend for XAuth credential verifica‐
tion.
charon.plugins.xauth-pam.pam_service [login]
PAM service to be used for authentication.
charon.plugins.xauth-pam.session [no]
Open/close a PAM session for each active IKE_SA.
charon.plugins.xauth-pam.trim_email [yes]
If an email address is received as an XAuth username, trim it to
just the username part.
charon.port [500]
UDP port used locally. If set to 0 a random port will be allo‐
cated.
charon.port_nat_t [4500]
UDP port used locally in case of NAT-T. If set to 0 a random
port will be allocated. Has to be different from charon.port,
otherwise a random port will be allocated.
charon.process_route [yes]
Process RTM_NEWROUTE and RTM_DELROUTE events.
charon.processor.priority_threads
Section to configure the number of reserved threads per priority
class see JOB PRIORITY MANAGEMENT in strongswan.conf(5).
charon.receive_delay [0]
Delay in ms for receiving packets, to simulate larger RTT.
charon.receive_delay_request [yes]
Delay request messages.
charon.receive_delay_response [yes]
Delay response 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 in strongswan.conf(5).
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.retry_initiate_interval [0]
Interval to use when retrying to initiate an IKE_SA (e.g. if DNS
resolution failed), 0 to disable retries.
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 in ms for sending packets, to simulate larger RTT.
charon.send_delay_request [yes]
Delay request messages.
charon.send_delay_response [yes]
Delay response 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 in
strongswan.conf(5).
charon.syslog.<facility>
<facility> is one of the supported syslog facilities, see LOGGER
CONFIGURATION in strongswan.conf(5).
charon.syslog.<facility>.<subsystem> [<default>]
Loglevel for a specific subsystem.
charon.syslog.<facility>.default [1]
Specifies the default loglevel to be used for subsystems for
which no specific loglevel is defined.
charon.syslog.<facility>.ike_name [no]
Prefix each log entry with the connection name and a unique
numerical identifier for each IKE_SA.
charon.syslog.identifier []
Global identifier used for an openlog(3) call, prepended to each
log message by syslog. If not configured, openlog(3) is not
called, so the value will depend on system defaults (often the
program name).
charon.threads [16]
Number of worker threads in charon. Several of these are
reserved for long running tasks in internal modules and plugins.
Therefore, make sure you don't set this value too low. The num‐
ber of idle worker threads listed in ipsec statusall might be
used as indicator on the number of reserved threads.
charon.tls.cipher []
List of TLS encryption ciphers.
charon.tls.key_exchange []
List of TLS key exchange methods.
charon.tls.mac []
List of TLS MAC algorithms.
charon.tls.suites []
List of TLS cipher suites.
charon.tnc.tnc_config [/etc/tnc_config]
TNC IMC/IMV configuration file.
charon.user []
Name of the user the daemon changes to after startup.
charon.x509.enforce_critical [yes]
Discard certificates with unsupported or unknown critical exten‐
sions.
libimcv.debug_level [1]
Debug level for a stand-alone libimcv library.
libimcv.load [random nonce gmp pubkey x509]
Plugins to load in IMC/IMVs with stand-alone libimcv library.
libimcv.stderr_quiet [no]
Disable output to stderr with a stand-alone libimcv library.
manager.database []
Credential database URI for manager. If it contains a password,
make sure to adjust the permissions of the config file accord‐
ingly.
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.
medsrv.database []
Mediation server database URI. If it contains a password, make
sure to adjust the permissions of the config file accordingly.
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 plug‐
in.
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.
pacman.database []
Database URI for the database that stores the package informa‐
tion. If it contains a password, make sure to adjust the permis‐
sions of the config file accordingly.
pacman.load []
Plugins to load in package manager.
pki.load []
Plugins to load in ipsec pki tool.
pool.database []
Database URI for the database that stores IP pools and configu‐
ration attributes. If it contains a password, make sure
to adjust the permissions of the config file accordingly.
pool.load []
Plugins to load in ipsec pool tool.
scepclient.load []
Plugins to load in ipsec scepclient tool.
starter.load []
Plugins to load in starter.
starter.load_warning [yes]
Disable charon plugin load option warning.
LOGGER CONFIGURATION
Options in strongswan.conf(5) provide a much more flexible way to con‐
figure loggers for the IKE daemon charon than using the charondebug
option in ipsec.conf(5).
Note: If any loggers are specified in strongswan.conf, charondebug does
not have any effect.
There are currently two types of loggers:
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 ver‐
bosity for the different subsystems of the daemon.
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
asn Low-level encoding/decoding (ASN.1, X.509 etc.)
enc Packet encoding/decoding encryption/decryption operations
tls libtls library messages
esp libipsec library messages
lib libstrongwan library messages
tnc Trusted Network Connect
imc Integrity Measurement Collector
imv Integrity Measurement Verifier
pts Platform Trust Service
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
}
}
}
JOB PRIORITY MANAGEMENT
Some operations in the IKEv2 daemon charon are currently implemented
synchronously and blocking. Two examples for such operations are commu‐
nication with a RADIUS server via EAP-RADIUS, or fetching CRL/OCSP
information during certificate chain verification. Under high load con‐
ditions, the thread pool may run out of available threads, and some
more important jobs, such as liveness checking, may not get executed in
time.
To prevent thread starvation in such situations job priorities were
introduced. The job processor will reserve some threads for higher
priority jobs, these threads are not available for lower priority,
locking jobs.
Implementation
Currently 4 priorities have been defined, and they are used in charon
as follows:
CRITICAL
Priority for long-running dispatcher jobs.
HIGH INFORMATIONAL exchanges, as used by liveness checking (DPD).
MEDIUM Everything not HIGH/LOW, including IKE_SA_INIT processing.
LOW IKE_AUTH message processing. RADIUS and CRL fetching block here
Although IKE_SA_INIT processing is computationally expensive, it is
explicitly assigned to the MEDIUM class. This allows charon to do the
DH exchange while other threads are blocked in IKE_AUTH. To prevent the
daemon from accepting more IKE_SA_INIT requests than it can handle, use
IKE_SA_INIT DROPPING.
The thread pool processes jobs strictly by priority, meaning it will
consume all higher priority jobs before looking for ones with lower
priority. Further, it reserves threads for certain priorities. A prior‐
ity class having reserved n threads will always have n threads avail‐
able for this class (either currently processing a job, or waiting for
one).
Configuration
To ensure that there are always enough threads available for higher
priority tasks, threads must be reserved for each priority class.
charon.processor.priority_threads.critical [0]
Threads reserved for CRITICAL priority class jobs
charon.processor.priority_threads.high [0]
Threads reserved for HIGH priority class jobs
charon.processor.priority_threads.medium [0]
Threads reserved for MEDIUM priority class jobs
charon.processor.priority_threads.low [0]
Threads reserved for LOW priority class jobs
Let's consider the following configuration:
charon {
processor {
priority_threads {
high = 1
medium = 4
}
}
}
With this configuration, one thread is reserved for HIGH priority
tasks. As currently only liveness checking and stroke message process‐
ing is done with high priority, one or two threads should be suffi‐
cient.
The MEDIUM class mostly processes non-blocking jobs. Unless your setup
is experiencing many blocks in locks while accessing shared resources,
threads for one or two times the number of CPU cores is fine.
It is usually not required to reserve threads for CRITICAL jobs. Jobs
in this class rarely return and do not release their thread to the
pool.
The remaining threads are available for LOW priority jobs. Reserving
threads does not make sense (until we have an even lower priority).
Monitoring
To see what the threads are actually doing, invoke ipsec statusall.
Under high load, something like this will show up:
worker threads: 2 or 32 idle, 5/1/2/22 working,
job queue: 0/0/1/149, scheduled: 198
From 32 worker threads,
2 are currently idle.
5 are running CRITICAL priority jobs (dispatching from sockets,
etc.).
1 is currently handling a HIGH priority job. This is actually the
thread currently providing this information via stroke.
2 are handling MEDIUM priority jobs, likely IKE_SA_INIT or CRE‐
ATE_CHILD_SA messages.
22 are handling LOW priority jobs, probably waiting for an EAP-
RADIUS response while processing IKE_AUTH messages.
The job queue load shows how many jobs are queued for each priority,
ready for execution. The single MEDIUM priority job will get executed
immediately, as we have two spare threads reserved for MEDIUM class
jobs.
IKE_SA_INIT DROPPING
If a responder receives more connection requests per seconds than it
can handle, it does not make sense to accept more IKE_SA_INIT messages.
And if they are queued but can't get processed in time, an answer might
be sent after the client has already given up and restarted its connec‐
tion setup. This additionally increases the load on the responder.
To limit the responder load resulting from new connection attempts, the
daemon can drop IKE_SA_INIT messages just after reception. There are
two mechanisms to decide if this should happen, configured with the
following options:
charon.init_limit_half_open [0]
Limit based on the number of half open IKE_SAs. Half open
IKE_SAs are SAs in connecting state, but not yet established.
charon.init_limit_job_load [0]
Limit based on the number of jobs currently queued for process‐
ing (sum over all job priorities).
The second limit includes load from other jobs, such as rekeying.
Choosing a good value is difficult and depends on the hardware and
expected load.
The first limit is simpler to calculate, but includes the load from new
connections only. If your responder is capable of negotiating 100 tun‐
nels/s, you might set this limit to 1000. The daemon will then drop new
connection attempts if generating a response would require more than 10
seconds. If you are allowing for a maximum response time of more than
30 seconds, consider adjusting the timeout for connecting IKE_SAs
(charon.half_open_timeout). A responder, by default, deletes an IKE_SA
if the initiator does not establish it within 30 seconds. Under high
load, a higher value might be required.
LOAD TESTS
To do stability testing and performance optimizations, the IKE daemon
charon provides the load-tester plugin. This plugin allows one 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 authenti‐
cate as any user.
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 rounds are
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 rounds, concatenate multiple meth‐
ods 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 one to run tests without DH calculation
overhead.
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 fail, as each SA gets
installed twice. To simulate the correct behavior, a fake kernel inter‐
face 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 one 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
VARIABLES
The variables used above are configured as follows:
${piddir} /var/run
${prefix} /usr
${random_device} /dev/random
${urandom_device} /dev/urandom
FILES
/etc/strongswan.conf configuration file
/etc/strongswan.d/ directory containing included config snippets
/etc/strongswan.d/charon/ plugin specific config snippets
SEE ALSOipsec.conf(5), ipsec.secrets(5), ipsec(8), charon-cmd(8)HISTORY
Written for the strongSwan project ⟨http://www.strongswan.org⟩ by
Tobias Brunner, Andreas Steffen and Martin Willi.
5.1.3STRONGSWAN.CONF(5)
