Limiting number of connections at once

Bulletproof · 08-08-2012, 07:23 PM

I'm wondering if it's possible to limit the number of connections total on at a single time.

I already know how to set connection limits per-IP but not the amount of connections all-together that can be connected to the server at a single time.

Not really sure if it's possible either. Would appreciate any help at all.

Using linux debian iptables.

chrism01 · 08-08-2012, 08:18 PM

It looks like somaxconn is most likely what you want http://serverfault.com/questions/271...e-of-somaxconn, but there are other params https://computing.llnl.gov/linux/slu...hroughput.html

That's just for generic TCP cxns; many services have their own configurable limit.

hawk1278 · 08-09-2012, 05:32 AM

You can do this with iptables.
/sbin/iptables -A INPUT -p tcp --syn --dport $port -m connlimit --connlimit-above N -j DROP

you can throw in --connlimit-mask and provide specific subnets as well. check the iptables man pages.

Bulletproof · 08-09-2012, 10:01 AM

Quote:

Originally Posted by hawk1278

You can do this with iptables.
/sbin/iptables -A INPUT -p tcp --syn --dport $port -m connlimit --connlimit-above N -j DROP

you can throw in --connlimit-mask and provide specific subnets as well. check the iptables man pages.

Sorry but doesn't that just limit the connections Per-IP, not the total connections from all-IPs on at a single time on the server?

Bulletproof · 08-09-2012, 10:20 AM

Quote:

Originally Posted by chrism01

It looks like somaxconn is most likely what you want http://serverfault.com/questions/271...e-of-somaxconn, but there are other params https://computing.llnl.gov/linux/slu...hroughput.html

That's just for generic TCP cxns; many services have their own configurable limit.

I'm looking for UDP since it's a gameserver (doesn't use PHP either) - not a webserver. Sorry for not mentioning that earlier on.