Manual Pages  — SETKEY

Meta-arguments are as follows:

src dst
	Source/destination of the secure communication is specified as IPv4/v6 address. The setkey utility can resolve a FQDN into numeric addresses. If the FQDN resolves into multiple addresses, setkey will install multiple SAD/SPD entries into the kernel by trying all possible combinations. -4, -6 and -n restricts the address resolution of FQDN in certain ways. -4 and -6 restrict results into IPv4/v6 addresses only, respectively. -n avoids FQDN resolution and requires addresses to be numeric addresses.
protocol	protocol is one of following:
esp	ESP based on rfc2406
esp-old
	ESP based on rfc1827
ah	AH based on rfc2402
ah-old	AH based on rfc1826
ipcomp	IPComp
tcp	TCP-MD5 based on rfc2385

spi	Security Parameter Index (SPI) for the SAD and the SPD. spi must be a decimal number, or a hexadecimal number with ‘0x’ prefix. SPI values between 0 and 255 are reserved for future use by IANA and they cannot be used.
extensions
	take some of the following:
-m mode
	Specify a security protocol mode for use. mode is one of following: transport, tunnel or any. The default value is any.
-r size
	Specify the bitmap size in octets of the anti-replay window. size is a 32-bit unsigned integer, and its value is one eighth of the anti-replay window size in packets. If size is zero or not specified, an anti-replay check does not take place.
-u id
	Specify the identifier of the policy entry in SPD. See policy.
-f pad_option
	defines the content of the ESP padding. pad_option is one of following:

zero-pad	All of the padding are zero.
random-pad	A series of randomized values are set.
seq-pad	A series of sequential increasing numbers started from 1 are set.

-fnocyclic-seq
	Do not allow cyclic sequence number.
-lh time -ls time
	Specify hard/soft life time duration of the SA.

algorithm

-E ealgo key
	Specify an encryption or Authenticated Encryption with Associated Data (AEAD) algorithm ealgo for ESP.
-E ealgo key -A aalgo key Specify a encryption algorithm ealgo, as well as a payload authentication algorithm aalgo, for ESP.
-A aalgo key
	Specify an authentication algorithm for AH.
-C calgo [-R]
	Specify a compression algorithm for IPComp. If -R is specified, the spi field value will be used as the IPComp CPI (compression parameter index) on wire as is. If -R is not specified, the kernel will use well-known CPI on wire, and spi field will be used only as an index for kernel internal usage.

key must be double-quoted character string, or a series of hexadecimal digits preceded by ‘0x’.

Possible values for ealgo, aalgo and calgo are specified in separate section.

src_range dst_range
	These are selections of the secure communication specified as IPv4/v6 address or IPv4/v6 address range, and it may accompany TCP/UDP port specification. This takes the following form: address address/prefixlen address[port] address/prefixlen[port] prefixlen and port must be a decimal number. The square brackets around port are necessary and are not manpage metacharacters. For FQDN resolution, the rules applicable to src and dst apply here as well.
upperspec
	The upper layer protocol to be used. You can use one of the words in /etc/protocols as upperspec, as well as icmp6, ip4, or any. The word any stands for "any protocol". The protocol number may also be used to specify the upperspec. A type and code related to ICMPv6 may also be specified as an upperspec. The type is specified first, followed by a comma and then the relevant code. The specification must be placed after icmp6. The kernel considers a zero to be a wildcard but cannot distinguish between a wildcard and an ICMPv6 type which is zero. The following example shows a policy where IPSec is not required for inbound Neighbor Solicitations:     spdadd ::/0 ::/0 icmp6 135,0 -P in none; NOTE: upperspec does not work in the forwarding case at this moment, as it requires extra reassembly at forwarding node, which is not implemented at this moment. Although there are many protocols in /etc/protocols, protocols other than TCP, UDP and ICMP may not be suitable to use with IPsec.
policy
	policy is expressed in one of the following three formats:
-P directiondiscard -P directionnone
protocol/mode/src-dst/level [...]

The direction of a policy must be specified as one of: out or in. The direction is followed by one of the following policy levels: discard, none, or ipsec. The discard policylevel means that packets matching the supplied indices will be discarded while none means that IPsec operations will not take place on the packet and ipsec means that IPsec operation will take place onto the packet. The protocol/mode/src-dst/level statement gives the rule for how to process the packet. The protocol is specified as ah, esp or ipcomp. The mode is either transport or tunnel. If mode is tunnel, you must specify the end-point addresses of the SA as src and dst with a dash, '-', between the addresses. If mode is transport, both src and dst can be omitted. The level is one of the following: default, use, require or unique. If the SA is not available in every level, the kernel will request the SA from the key exchange daemon. A value of default tells the kernel to use the system wide default protocol e.g.,amp; the one from the esp_trans_deflev sysctl variable, when the kernel processes the packet. A value of use means that the kernel will use an SA if it is available, otherwise the kernel will pass the packet as it would normally. A value of require means that an SA is required whenever the kernel sends a packet matched that matches the policy. The unique level is the same as require but, in addition, it allows the policy to bind with the unique out-bound SA. For example, if you specify the policy level unique, racoon(8) will configure the SA for the policy. If you configure the SA by manual keying for that policy, you can put the decimal number as the policy identifier after unique separated by colon ‘:amp;’ as in the following example: unique:number. In order to bind this policy to the SA, number must be between 1 and 32767, which corresponds to extensions -u of manual SA configuration.

When you want to use an SA bundle, you can define multiple rules. For example, if an IP header was followed by an AH header followed by an ESP header followed by an upper layer protocol header, the rule would be:

    esp/transport//require ah/transport//require;

The rule order is very important.