Thorsten Greiner wrote: > > * Andre Oppermann <andre_at_freebsd.org> [2004-01-09 11:34]: > > You can simply increase net.inet.tcp.minmssoverload to any > > higher value. I suggest 2,000 as next step. If set it to > > 0 the check will be disabled entirely. > > Setting net.inet.tcp.minmssoverload to 4000 fixed my problem(s). Ok, that's an important information. > > This makes we wonder why the Oracle database server is sending > > so many small packets. Is your JBoss application doing connection > > pooling (eg. multiplexing multiple SQL sessions over one tcp > > session)? > > It performs connection pooling on the application layer, i.e. it > opens several connections and pools them to avoid reopening them. As > far as I understand each Oracle connection is associated with a TCP > connection - there is no pooling on the TCP level. Ok. Might it be that Oracle is setting the TCP_NODELAY option on its sending socket? I guess it is difficult to find that out... > While I have read your commit message thoroughly I am not sure I > have understood the consequences of the new mechanism. Will the > exchange of many small packets trigger a connection drop? Yes. Once you receive more than 1,000 tcp packets per second whose average size is below the net.inet.tcp.minmss value, then it will assume a malicious DoS attack. It appears that the default value of 1,000 is too low. -- AndreReceived on Fri Jan 09 2004 - 05:24:00 UTC
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