Re: After many hours all outbound connections get stuck in SYN_SENT

From: Ilpo Järvinen
Date: Wed Dec 19 2007 - 16:28:09 EST


On Wed, 19 Dec 2007, Eric Dumazet wrote:

> James Nichols a écrit :
> > On 12/19/07, Eric Dumazet <dada1@xxxxxxxxxxxxx> wrote:
> > > James Nichols a écrit :
> > > > > So you see outgoing SYN packets, but no SYN replies coming from the
> > > > > remote
> > > > > peer ? (you mention ACKS, but the first packet received from the
> > > > > remote
> > > > > peer should be a SYN+ACK),
> > > > Right, I meant to say SYN+ACK. I don't see them coming back.
> > > So... Really unlikely a linux problem, but ...
> > >
> >
> >
> > I don't know how you can be so sure. Turning tcp_sack off instantly
> > resovles the problem and all connections are succesful. I can't
> > imagine even the most far-fetched scenario where a router or every
> > single remote endpoints would suddenly stop causing the problem just
> > by removing a single TCP option.

You could also check if you can pull same trick off by touching
tcp_timestamps. It affects the TCP header as well.



--
i.