freebsd-nq/share/man/man4/enc.4
Andrew Thompson bdea400f3b Add a pseudo interface for packet filtering IPSec connections before or after
encryption. There are two functions, a bpf tap which has a basic header with
the SPI number which our current tcpdump knows how to display, and handoff to
pfil(9) for packet filtering.

Obtained from:	OpenBSD
Based on:	kern/94829
No objections:	arch, net
MFC after:	1 month
2006-06-26 22:30:08 +00:00

83 lines
2.7 KiB
Groff

.\" $OpenBSD: enc.4,v 1.22 2006/05/26 08:51:29 jmc Exp $
.\"
.\" Copyright (c) 1999 Angelos D. Keromytis
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.\" $FreeBSD$
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.Dd June 16, 2006
.Dt ENC 4
.Os
.Sh NAME
.Nm enc
.Nd Encapsulating Interface
.Sh SYNOPSIS
.Cd "device enc"
.Sh DESCRIPTION
The
.Nm
interface is a software loopback mechanism that allows hosts or
firewalls to filter
.Xr fast_ipsec 4
traffic using any firewall package that hooks in via the
.Xr pfil 9
framework.
.Pp
The
.Nm
interface allows an administrator
to see outgoing packets before they have been processed by
.Xr fast_ipsec 4 ,
or incoming packets after they have been similarly processed, via
.Xr tcpdump 8 .
.Pp
The
.Dq enc0
interface inherits all IPsec traffic.
Thus all IPsec traffic can be filtered based on
.Dq enc0 ,
and all IPsec traffic could be seen by invoking
.Xr tcpdump 8
on the
.Dq enc0
interface.
.Sh EXAMPLES
To see all outgoing packets before they have been processed via
.Xr fast_ipsec 4 ,
or all incoming packets after they have been similarly processed:
.Pp
.Dl # tcpdump -i enc0
.Sh SEE ALSO
.Xr bpf 4 ,
.Xr fast_ipsec 4 ,
.Xr ipf 4 ,
.Xr ipfw 4 ,
.Xr pf 4 ,
.Xr tcpdump 8