Using hashlimit in iptables
iptables -I INPUT -m hashlimit -m tcp -p tcp –dport 23032 –hashlimit 1/min –hashlimit-mode srcip –hashlimit-name ssh -m state –state NEW -j ACCEPT
This rule limits one connection to the SSH port from one IP address per minute.
hashlimit match options
--hashlimit-upto max average match rate
[Packets per second unless followed by
/sec /minute /hour /day postfixes]
–hashlimit-above min average match rate
–hashlimit-mode mode is a comma-separated list of
dstip,srcip,dstport,srcport (or none)
–hashlimit-srcmask source address grouping prefix length
–hashlimit-dstmask destination address grouping prefix length
–hashlimit-name name for /proc/net/ipt_hashlimit
–hashlimit-burst number to match in a burst, default 5
–hashlimit-htable-size number of hashtable buckets
–hashlimit-htable-max number of hashtable entries
–hashlimit-htable-gcinterval interval between garbage collection runs
–hashlimit-htable-expire after which time are idle entries expired?
