/proc/net/ipsec_eroute lists the IPSEC extended routing tables, which control what (if any) processing is applied to non-encrypted packets arriving for IPSEC processing and forwarding. At this point it is a read-only file.
A table entry consists of:
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Addresses are written as IPv4 dotted quads or IPv6 coloned hex, protocol is one of "ah", "esp", "comp" or "tun" and SPIs are prefixed hexadecimal numbers where the prefix '.' is for IPv4 and the prefix ':' is for IPv6
SAIDs are written as "protoafSPI@edst". There are also five "magic" SAIDs that have special meaning:
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1867 172.31.252.0/24:0 -> 0.0.0.0/0:0 => tun0x130@192.168.43.1:0
() ()
means that 1,867 packets have been sent to an eroute that has been set up to protect traffic between the subnet 172.31.252.0 with a subnet mask of 24 bits and the default address/mask represented by an address of 0.0.0.0 with a subnet mask of 0 bits using the local machine as a security gateway on this end of the tunnel and the machine 192.168.43.1 on the other end of the tunnel with a Security Association IDentifier of tun0x130@192.168.43.1 which means that it is a tunnel mode connection (4, IPPROTO_IPIP) with a Security Parameters Index of 130 in hexadecimal with no identities defined for either end.
746 192.168.2.110/32:0 -> 192.168.2.120/32:25 => esp0x130@192.168.2.120:6
() ()
means that 746 packets have been sent to an eroute that has been set up to protect traffic sent from any port on the host 192.168.2.110 to the SMTP (TCP, port 25) port on the host 192.168.2.120 with a Security Association IDentifier of tun0x130@192.168.2.120 which means that it is a transport mode connection with a Security Parameters Index of 130 in hexadecimal with no identies defined for either end.
125 3049:1::/64 -> 0:0/0 => tun:130@3058:4::5 () ()
means that 125 packets have been sent to an eroute that has been set up to protect traffic between the subnet 3049:1:: with a subnet mask of 64 bits and the default address/mask represented by an address of 0:0 with a subnet mask of 0 bits using the local machine as a security gateway on this end of the tunnel and the machine 3058:4::5 on the other end of the tunnel with a Security Association IDentifier of tun:130@3058:4::5 which means that it is a tunnel mode connection with a Security Parameters Index of 130 in hexadecimal with no identies defined for either end.
42 192.168.6.0/24:0 -> 192.168.7.0/24:0 => %passthrough
means that 42 packets have been sent to an eroute that has been set up to pass the traffic from the subnet 192.168.6.0 with a subnet mask of 24 bits and to subnet 192.168.7.0 with a subnet mask of 24 bits without any IPSEC processing with no identies defined for either end.
2112 192.168.8.55/32:0 -> 192.168.9.47/24:0 => %hold (east) ()
means that 2112 packets have been sent to an eroute that has been set up to hold the traffic from the host 192.168.8.55 and to host 192.168.9.47 until a key exchange from a Key Management daemon succeeds and puts in an SA or fails and puts in a pass or drop eroute depending on the default configuration with the local client defined as "east" and no identy defined for the remote end.
2001 192.168.2.110/32:0 -> 192.168.2.120/32:0 =>
esp0xe6de@192.168.2.120:0 () ()
means that 2001 packets have been sent to an eroute that has been set up to protect traffic between the host 192.168.2.110 and the host 192.168.2.120 using 192.168.2.110 as a security gateway on this end of the connection and the machine 192.168.2.120 on the other end of the connection with a Security Association IDentifier of esp0xe6de@192.168.2.120 which means that it is a transport mode connection with a Security Parameters Index of e6de in hexadecimal using Encapsuation Security Payload protocol (50, IPPROTO_ESP) with no identies defined for either end.
1984 3049:1::110/128 -> 3049:1::120/128 =>
ah:f5ed@3049:1::120 () ()
means that 1984 packets have been sent to an eroute that has been set up to authenticate traffic between the host 3049:1::110 and the host 3049:1::120 using 3049:1::110 as a security gateway on this end of the connection and the machine 3049:1::120 on the other end of the connection with a Security Association IDentifier of ah:f5ed@3049:1::120 which means that it is a transport mode connection with a Security Parameters Index of f5ed in hexadecimal using Authentication Header protocol (51, IPPROTO_AH) with no identies defined for either end.
/proc/net/ipsec_eroute, /usr/local/bin/ipsec
ipsec(8), ipsec_tncfg(5), ipsec_spi(5), ipsec_spigrp(5), ipsec_klipsdebug(5), ipsec_eroute(8), ipsec_version(5), ipsec_pf_key(5)
Written for the Linux FreeS/WAN project <m[blue]http://www.freeswan.org/m[]> by Richard Guy Briggs.
Paul Wouters