Messages in this thread | | | Date | Wed, 19 Dec 2007 12:43:13 -0500 | From | "James Nichols" <> | Subject | Re: After many hours all outbound connections get stuck in SYN_SENT |
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On 12/19/07, Eric Dumazet <dada1@cosmosbay.com> 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.
> > I can take these captures and take a look at the results. > > Unfortunately, I don't think I'll be able to make the captures > > available to the general public. > > I dont understand, why dont you change IPs to mask them with 192.168.X.Y, or > just ME, and peer1, peer2, peer...
I will see if I can do that, but it's major pain with 2000 hosts. Plus, there is application data in the packets that I can't allow into the public domain. I really don't think I can pull it off... I literally would have to go through our legal department.
> > Random ideas : > > 1) Is your server behind a NET router or something ?
What's a NET router? I am behind a Cisco router and a firewall, but these network components have completely been replaced/rebuilt several times in the 4+ years that we've had this problem. I've looked at the logs there and neither are doing anything other than passing the traffic along.
> 2) Are you sure you are not using connection tracking, and hit a limit on it ?
I'm using ip_conntrack, but the limit I have for max entries is 65K. The most I've seen in there are a couple thousand- that was one of the first things I monitored very closely. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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