>Number:         14319
>Category:       kern
>Synopsis:       NAT with only one physical interface is broken.
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Oct 21 06:13:00 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Johan Ihren
>Release:        1.5X, August 7, 2001
>Organization:
	Autonomica AB
>Environment:
	i386, 
System: NetBSD snout.autonomica.se 1.5X NetBSD 1.5X (SNOUT) #41: Thu Sep 27 22:10:40 CEST 2001 johani@snout.autonomica.se:/usr/store/source/netbsd/kernels.i386/SNOUT i386
Architecture: i386
Machine: i386
>Description:
	Presently it is (as far as I can tell) impossible to use NAT with 
	only one physical interface since the NAT gets confused over which
	source address to use when communicating with hosts on the "inside".

>How-To-Repeat:
	ifconfig ep0 192.168.1.1/24
	ifconfig ep0 10.1.1.1/24

	Use an ipnat.conf somewhat like this:

	#!/usr/sbin/ipnat -v -f -
	map ep0 192.168.1.0/24 -> 10.1.1.1/32 portmap tcp/udp 40000:60000
	map ep0 192.168.1.0/24 -> 10.1.1.1/32
	map ep0 192.168.1.0/24 -> 10.1.1.1/32 proxy port ftp ftp/tcp

	The try pinging (from another box) the 192.168.1.1 address and se
	return packets from 10.1.1.1.

	As soon as the NAT is turned off (by ipnat -C) the source address
	changes to the (correct) 192.168.1.1.

>Fix:
	Don't know.
>Release-Note:
>Audit-Trail:
>Unformatted: