nanog mailing list archives

Re: TCP time_wait and port exhaustion for servers


From: JÁKÓ András <jako.andras () eik bme hu>
Date: Wed, 5 Dec 2012 17:56:06 +0100 (CET)

 Ray,

With a 60 second timeout on TIME_WAIT, local port identifiers are tied
up from being used for new outgoing connections (in this case a proxy
server).  The default local port range on Linux can easily be
adjusted; but even when bumped up to a range of 32K ports, the 60
second timeout means you can only sustain about 500 new connections
per second before you run out of ports.

Is that 500 new connections per second per {protocol, remote address, 
remote port} tuple, that's too few for your proxy? (OK, this tuple is more 
or less equivalent with only {remote address} if we talk about a web 
proxy.) Just curious.

Regards,
András


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