kern/38773: ipf/ipnat broken in 4.99.63

[paul%whooppee.com@localhost]

>Number:         38773
>Category:       kern
>Synopsis:       ipf/ipnat broken in 4.99.63
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed May 28 00:15:00 +0000 2008
>Originator:     Paul Goyette
>Release:        4.99.63
>Organization:
>Environment:
NetBSD quicky.whooppee.com 4.99.63 NetBSD 4.99.63 (QUICKY (ASUS M2N32 WS) 
2008-05-23 19:09:17) #4: Sat May 24 05:04:53 PDT 2008  
paul%quicky.whooppee.com@localhost:/build/obj/amd64/sys/arch/amd64/compile/QUICKY
 amd64

>Description:
The recent import of ipf appears broken.

With no ipf rules defined, but with ipnat enabled, I am unable to ssh from 
another machine into the 4.99.63 box.  SSH -d shows that the TCP session is 
established, but fails during the key exchange.  I can open an ftp session but 
unable to perform an ls.  ICMP pings are properly responded to.  NFS mounts of 
remote file systems also work, but any attempt to to a 'df' or to otherwise 
access the mounted directory fails.

I'm suspecting a problem with packet size, but am unable to confirm.  I have 
had to revert this machine back to 4.99.62 (from May 14th) since I cannot 
disable ipnat (my VoIP gateway needs an IP address).
>How-To-Repeat:
See description.
>Fix: