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From: "Kristof Provost" <kp@FreeBSD.org>
To: "Bakul Shah" <bakul@bitblocks.com>
Cc: freebsd-net@freebsd.org
Subject: Re: pf & NAT issue
Date: Fri, 20 Jan 2017 11:48:04 +0100
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On 20 Jan 2017, at 9:35, Bakul Shah wrote:
> pf seems to drop NAT connections quite a bit. This seems to
> happen much more frequently if there are delays involved (slow
> server or interactive use). Almost seems like pf losing
> track of NATted connections due to an uninitialized
> variable....  Often a retry or two works. Connecting from
> outside to forwarded connections to NATTED hosts works fine.
>
> This problem started after ungrading to freebsd-10. Is there a
> bug fix in works or a known work around (other than using ipfw
> or reverting to 9, which I don't want to do)?
>
The problem you describe doesn’t immediately ring a bell.

We’ll have to gather a bit more information:

  * What FreeBSD version are you running exactly?
  * What’s your pf.conf?
  * Can you perform a network capture of rejected/failed connections? 
Ideally
    both on LAN and WAN on the gateway machine. Please capture full 
packets (so
    tcpdump -s0 -w lan.pcap) as pcap files).
  * What networking cards are you using?

Regards,
Kristof