3

I need to ensure on my server that maximum new ssh connections per minute are not more then 5.

sudo /sbin/iptables -A INPUT -p tcp --syn --dport 22 -m connlimit --connlimit-above 5 -j REJECT

Above IPtables rule work for me, but it will not allow new connections after one minute.

Any pointers how to achieve this?

4

Add --reject-with tcp-reset so that the rejected connections get closed gracefully otherwise you're going to have a bunch of SYN_WAITs sitting around.

sudo /sbin/iptables -A INPUT -p tcp --syn --dport 22 -m connlimit --connlimit-above 5 -j REJECT --reject-with tcp-reset

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.