[tproxy] TPROXY behavior when there is no listening socket at the target port

Balazs Scheidler bazsi at balabit.hu
Thu Apr 15 10:08:08 CEST 2010

On Thu, 2009-12-03 at 12:44 -0800, Ashwani Wason wrote:
> Hi All,
> If one has a TPROXY rule that redirects the packets to a local socket
> on which there is no one listening then the SYN packets keep getting
> dropped silently. Is this expected? Without knowing that this would
> happen my natural expectation was that a RST would be sent by local
> TCP. Is this by design or a bug?

You can change this behaviour by changing your iptables rules, in this
case the "-m socket" rule doesn't match and the default policy (or the
next rule) of your iptables ruleset will determine what action is taken
for the given packet.


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