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    SubjectRe: After many hours all outbound connections get stuck in SYN_SENT
    James Nichols a écrit :
    >> Here is a purely hypothethical (and in practice unlikely) idea:
    >> Java opens up too many sockets (more than you really request) and the
    >> kernel, for whatever reason, does not deliver packets to programs
    >> which have maxed out their fds. Well it would already help if the
    >> java blob was split into multiple blobs (assuming the problem
    >> persists), as the best testcase is the smallest possible one. So if
    >> it is reproducable without the web blob, great step there.
    > Right, I don't disagree with you there. FWIW, I can disable entire
    > parts of the application and have already narrowed down reproduction
    > of this issue to the 200 threads that make the webservice calls, so it
    > doesn't have anything to do with any of the GUI or other background
    > services that my application executes.
    > You said:
    >> Well you could still blame Java. I am sure that if you program was C,
    >> the problem could be narrowed down much easier.
    > I'm curious to know how this problem would be easier to narrow down if
    > it were written in C.
    Well... please dont start a flame war :(

    Back to your SYN_SENT problem, I suppose the remote IP is known, so you
    probably could post here the result of a tcdpump ?

    tcpdump -p -n -s 1600 host IP_of_problematic_peer -c 500

    Most probably remote peer received too many attempts from you, and a
    anti DOS mechanism is droping all SYN packets.

    Ah well... I remember now that you mentioned tcp_sack setting had an
    effect, so forget the "Most probably..." and give some tcpdump traces :)

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      Last update: 2007-12-18 19:35    [W:0.021 / U:10.676 seconds]
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