Limit to number of listening ports in linux

Question

I have tried to launch a script to listen to thousands of tcp ports (1000 to 10000) but it appears to be hitting a limit of 1024 listening ports. I've confirmed this via netstat and closed ports above certain ranges.

Is there a fixed limit of listening ports in linux and how, if possible, can this be raised?

what does `sysctl net.ipv4.ip_local_port_range` tell you? – Mike Feb 07 '15 at 14:17 — Mike, Feb 07 '15 at 14:17
Output below net.ipv4.ip_local_port_range = 32768 61000 – loloy.batoytoy Feb 08 '15 at 00:28 — loloy.batoytoy, Feb 08 '15 at 00:28

score 4 · Answer 1 · answered Feb 07 '15 at 14:18

4

You are probably hitting at nofile limit, which is by default 1024.

Try raising ulimit -n in your shell before running the program, like:

$ ulimit -n 20480; ./myprogram

Offcourse, you have to have priviledge to raise nofile limit so high, so check current soft and hard limits with:

$ ulimit -a

And raise them in /etc/security/limits.conf or /etc/security/limits.d/*conf

answered Feb 07 '15 at 14:18

Jakov Sosic

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I have raised soft and hard nofile limits from 1024/4096 to 16384/32768 but still hitting the 1024 listening ports limit. – loloy.batoytoy Feb 08 '15 at 00:27

score 0 · Answer 2 · answered Feb 08 '15 at 03:49

0

By the way I didn't mention that the program/script is launched by xinetd, and that xinetd is ignoring the ulimit nofile settings, looking at the xinetd source now to try and bypass this limitation.

answered Feb 08 '15 at 03:49

loloy.batoytoy

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Limit to number of listening ports in linux

2 Answers2