On Mon, 2012-10-01 at 16:01 -0400, David Miller wrote:

From: Dave Jones <redacted>
Date: Mon, 1 Oct 2012 15:34:34 -0400

quoted

On Mon, Oct 01, 2012 at 11:15:50AM +0200, Eric Dumazet wrote:
 > > 
 > > $ netstat -s
 > > Icmp:
 > >      4 ICMP messages received
 > >      4 input ICMP message failed.
 > >      ICMP input histogram:
 > >          echo replies: 4
 > 
 > So icmp replies come back and are delivered to host instead of being
 > forwarded.
 > 
 > I wonder if MASQUERADE broke...

I hit something that sounds just like this a few months back..
http://lists.openwall.net/netdev/2012/07/25/53

It "went away" a few builds later, but I've seen it happen
again from time to time.

Yep I remembe that report.

If you can find a way to more reliably trigger the case, that would
help us immensely.

I am building a KMEMCHECK kernel, as a last try before my night ;)