i386/72210: ipnat problem with IP Fastforward enabled

[Remy de Ruysscher]

>Number:         72210
>Category:       i386
>Synopsis:       ipnat problem  with IP Fastforward enabled
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-i386
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Sep 30 18:50:11 GMT 2004
>Closed-Date:
>Last-Modified:
>Originator:     Remy de Ruysscher
>Release:        FreeBSD 5.3-BETA6
>Organization:
>Environment:
FreeBSD defiant.unix-asp.com 5.3-BETA6 FreeBSD 5.3-BETA6 #5: Mon Sep 27 01:04:37 CEST 2004     root at defiant.unix-asp.com:/usr/obj/usr/src/sys/GENERIC  i386

>Description:
ipnat is not working correctly after enabling IP Fastforward. 
ipmon shows NAT:MAP and NAT:RDR connections but don't seem to work on clients pc's.

I couldn't find any solutions at the usual places. Andre Opperman suggested I created this PR.
>How-To-Repeat:
Enable IP fastforward. sysctl net.inet.ip.fastforwarding=1 
>Fix:
Disable IP fastforward. sysctl net.inet.ip.fastforwarding=0
>Release-Note:
>Audit-Trail:
>Unformatted: