Paul Wouters

placeholder to suppress warning

IPSEC_TNCFG 5 27 Jun 2000 libreswan Executable programs
ipsec_tncfg lists IPSEC virtual interfaces attached to real interfaces
`ipsec` tncfg
cat/proc/net/ipsec_tncfg

## KLIPS

Note that tncfg is only supported on the KLIPS stack which uses ipsecX interfaces bound to physical interfaces

## DESCRIPTION

`/proc/net/ipsec_tncfg` is a read-only file which lists which IPSEC virtual interfaces are attached to which real interfaces, through which packets will be forwarded once processed by IPSEC.

Each line lists one ipsec I/F. A table entry consists of:

+

  an ipsec virtual I/F name

+

  a visual and machine parsable separator '->', separating the virtual I/F and the physical I/F,

+

  a physical I/F name, to which the ipsec virtual I/F is attached or NULL if it is not attached,

+

  the keyword mtu=,

+

  the MTU of the ipsec virtual I/F,

+

  the automatically adjusted effective MTU for PMTU discovery, in brackets,

+

  a visual and machine parsable separator '->', separating the virtual I/F MTU and the physical I/F MTU,

+

  the MTU of the attached physical I/F.

## EXAMPLES

`ipsec2 -> eth3 mtu=16260(1443) -> 1500`

shows that virtual device ipsec2 with an MTU of `16260` is connected to physical device eth3 with an MTU of `1500` and that the effective MTU as a result of PMTU discovery has been automatically set to `1443.`

`ipsec0 -> wvlan0 mtu=1400(16260) -> 1500`

shows that virtual device ipsec0 with an MTU of `1400` is connected to physical device wvlan0 with an MTU of `1500` and no PMTU packets have gotten far enough to bump down the effective MTU from its default of 16260.

`ipsec3 -> NULL mtu=0(0) -> 0`

shows that virtual device ipsec3 is not connected to any physical device.

## FILES

/proc/net/ipsec_tncfg, /usr/local/bin/ipsec

## SEE ALSO

ipsec(8), ipsec_manual(8), ipsec_eroute(5), ipsec_spi(5), ipsec_spigrp(5), ipsec_klipsdebug(5), ipsec_tncfg(8), ipsec_version(5), ipsec_pf_key(5)

## HISTORY

Written for the Linux FreeS/WAN project <http://www.freeswan.org/> by Richard Guy Briggs.