[1117] in linux-net channel archive
Re: Sockets stuck in SYN_RECV filling up the accept queue...
daemon@ATHENA.MIT.EDU (Alan Cox)
Tue Sep 19 14:38:49 1995
From: Alan Cox <alan@cymru.net>
To: guru@ncm.com (Simon Janes)
Date: Tue, 19 Sep 1995 09:33:30 +0100 (BST)
Cc: linux-net@vger.rutgers.edu
In-Reply-To: <Pine.LNX.3.91.950918154201.16890O-100000@savvy.ncm.com> from "Simon Janes" at Sep 18, 95 03:45:31 pm
> I am fighting with a lousy TCP/IP WINSOCK package that has developed a
> very bad bug. (Core Internet connect (Run away! Run away!. you get the
> idea)).
Yeah, old hat.
> It botches the connection and fills up the accept-queue until no more
> connections can be started.
Correct.
> Does Linux ever expire and flush these dead connections, and if it does,
> which version of the kernel implements this?
Yes. The default timeout is about 12 minutes. Change tcp_conn_recv if it
worries you, 2 minutes is akin to BSD's timeout.
> This has real good/bad potential for a method of denial-of-service
> attacks. (I don't know how other stacks react under the same conditions...)
The same way - its a protocol rather than OS flaw.
Alan
