View source for Limiting number of simultaneous connections

[[Main Page|Home]] > [[CentOS]] > [[CentOS 6.x]] > [[Iptables configuration]] > [[Limiting number of simultaneous connections]]

==Using connlimit module==

We can use connlimit module of iptables to limit number of simultaneous connections to server in following manner
<pre>
iptables -I INPUT -p tcp --syn --dport 22 -m connlimit --connlimit-above 1 -j REJECT
</pre>
This will allow only one ssh connection to server per client.

To limit number of simultaneous connections based on subnets we can use below syntax
<pre>
iptables -p tcp --syn --dport 22 -m connlimit --connlimit-above 16 --connlimit-mask 24 -j REJECT
</pre>
This would allow only 16 connections from each /24 network.




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