Kernel TCP tuning

[Tyler Aviss]

My understanding is that the following setting basically sets the range of
high "local ports" used for outgoing connections

Either in sysctl.conf
/proc/sys/net/ipv4/ip_local_port_range = LOW HIGH

This can also be set by using sysctl or echoing to proc (but lost on
reboot).



My question is, what would be a symptom of exhausting the port pool?
Say if you have a port range of 10001 15000, and you attempt connection
#5001... what happens?

Is there something visible in dmesg/kern.log/syslog that indicates an error
opening ports? Do you see the port opening/connection attempt time out, or
just block?

I know if you start nipping at the limits of your max filehandles, an
kernel error is rather apparent, but I'm not sure what happens for ports.

As most people prefer to leave this at the default, there isn't a lot of
information other than how to set the port range




-- 
Tyler Aviss
Systems Support
LPIC/LPIC-2/DCTS/CLA

"Computers don't make mistakes. They can, however, execute those provided
to them very quickly"
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