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Re: troubles with ipnat TCP entries

2008/5/4 Manuel Bouyer <>:
> Hi,
>  I upgraded my home router to yesterday's current, and since then I have
>  troubles with ipnat: it seems to keep states for a lot of connections
>  which have been closed by either the application or the server,
>  while it closes TCP connection which are still active (e.g. an imaps
>  session initiated from mutt). FWIW, this is on a sparc (so big-endian)
>  machine.
>  Attached is the output of ipnat -lv on this box.
>  Notice that there's a lot of TCP map to remote host port 80 which have been
>  closed from the host or server side (a netstat on the nated host confirmes
>  this). These have a long TTL.
>  On the other hand, my connection to port 993 (the first entry in
>  the output below) has a ttl of only 465. This is the connection which is
>  dropped by the NAT box quite fast, while mutt had the connection to the
>  server still open.
>  Does anyone else have noticed this problem, or have an idea about it ?
>  --
>  Manuel Bouyer <>
>      NetBSD: 26 ans d'experience feront toujours la difference
>  --

Yes, for some time (at least a month) I have seen a similar behaviour:
I have a i386-box running current functioning as my NAT gateway and
after some time it collects a lot of NAT entries. As a user I
typically observe this when I use gmail from a machine on my local LAN
and the browser after a while cannot connect to the server.

It took me some time to suspect my gateway machine and then reboot
this machine would solve the problem for a while. Later I observed
that when it is stuck it typically has 1500-2000+ entries in the NAT
table and that running ipnat -F would clear it up without a reboot.

- Erik

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