Re: Hung Port

Jan Engelhardt
2007-01-17T16:57:19Z

>Last week I had a port (TCP:52557) that was mysteriously unavailable on
>my ubuntu machine (running kernel 2.6.15-27-k7 #1 SMP PREEMPT). If you
>tried to bind to it, it was unavailable. However, nmap (both to
>localhost and from an external host) reported the port closed. fuser,
>lsof, and netstat had no record of the port being used.

Did your application forgot to set SO_REUSEADDR?

> Our firewall
>logs didn't show any unusual traffic to the machine. Nor did they show
>any traffic at all to/from that port on the machine. After checking
>everything I could think of, I rebooted it, and there were no ports that
>were unavailable in this way when it came back up. This morning another
>hung port has appeared (TCP:43355). My best guess is that this is an
>ephemeral port that has somehow gotten hung in the kernel somewhere.
>Has anyone seen anything like this and/or is there anything else I could
>look at to figure it out?

-`J'
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