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    SubjectRe: After many hours all outbound connections get stuck in SYN_SENT
    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 ...

    >> When the problem comes, instead of restarting the application, please take a
    >> tcpdump of say 10.000 packets.
    >> Then turn off tcp_sack and take a 2nd tcpdump sample, and make both samples
    >> available to us.
    > 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...

    >> If turning off tcp_sack makes the problem go away, why dont you turn it off
    >> all the time ?
    > Unfortunately, I think that will be the answer if I can't get any help
    > fixing this problem in the kernel. It's a bummer, because many of the
    > remote hosts my application communicates with are on wireless links,
    > so there may be performance implications to turning SACK off.

    Random ideas :

    1) Is your server behind a NET router or something ?
    2) Are you sure you are not using connection tracking, and hit a limit on it ?

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      Last update: 2007-12-19 18:11    [W:0.021 / U:106.684 seconds]
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