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[Linux]Rate limit a connection with iptables
On a quick note
I had to limit the amount of packages that was directed to a single port. Usually this can be configure within the boundaries of the application. However this was an UDP based application and I wasn’t aware of any configuration parameters what would have allow this.
So I jumped to the firewall and limit the rate via iptables:
iptables -A FORWARD -s 0.0.0.0/0 -d 10.0.0.3/32 \ -p udp \ -i eth0 \ -o virbr0 \ --dport 9987\ -m state --state NEW \ -m limit --limit 5/second \ -j ACCEPT iptables -A FORWARD -s 0.0.0.0/0 -d 10.0.0.3/32 -p udp -i eth0 -o virbr0 --dport 9987\ -j LOG --log-prefix "BRUST UDP DROP " --log-ip-options iptables -A FORWARD -s 0.0.0.0/0 -d 10.0.0.3/32 -p udp -i eth0 -o virbr0 --dport 9987 -j DROP
This will allow up to 5 new connection to the port at the same time. When more connection are occur they will be dropped and logged.