TCP Logs Why "Connection attempt to closed port"

Daniel Bye freebsd-questions at slightlystrange.org
Mon Sep 20 14:21:41 UTC 2010


On Mon, Sep 20, 2010 at 11:58:38AM +0100, David Southwell wrote:
> 
> Large quantities of these errors constantly appear in log/dmesg.today.
> 
> Can anyone explain what is going on and whether any action is needed. If so 
> how to go about tracing the cause.

I think you probably have the net.inet.tcp.log_in_vain sysctl set to
something other than 0, causing the kernel to log these connection attempts
on ports where no service is listening. It is probably nothing to worry
about.

If you want to turn these warnings off, check in your /etc/rc.conf for
`log_in_vain=1' or similar and remove it - the default, set in
/etc/defaults/rc.conf, is to not log these attempts. 

Dan

-- 
Daniel Bye
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