I want to limit connections per IP for a specific UDP port. I got it working for TCP, but somehow it doesn't work on UDP. These are my rules:
For TCP (working)
iptables -A INPUT -p tcp --syn --dport 7787 -m connlimit --connlimit-above 3 -j REJECT --reject-with tcp-reset
iptables -A INPUT -p tcp --syn --dport 7788 -m connlimit --connlimit-above 3 -j REJECT --reject-with tcp-reset
For UDP
iptables -A INPUT -p udp --dport 7787 -m connlimit --connlimit-above 3 -j REJECT
iptables -A INPUT -p udp --dport 7788 -m connlimit --connlimit-above 3 -j REJECT
According to the man pages this should work (atleast how I understand it), but I still get flooded by single IP's sometimes.