server:~# iptables -L -v Chain INPUT (policy ACCEPT 13166 packets, 1372K bytes) pkts bytes target prot opt in out source destination 2 332 tcp -- any any anywhere anywhere tcp dpt:ssh recent: SET name: SSH side: source 2 332 SSH_WHITELIST tcp -- any any anywhere anywhere tcp dpt:ssh 0 0 ULOG tcp -- any any anywhere anywhere tcp dpt:ssh recent: CHECK seconds: 60 hit_count: 4 TTL-Match name: SSH side: source ULOG copy_range 0 nlgroup 1 prefix `SSH_brute_force' queue_threshold 1 0 0 DROP tcp -- any any anywhere anywhere tcp dpt:ssh recent: CHECK seconds: 60 hit_count: 4 TTL-Match name: SSH side: source Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 15452 packets, 5071K bytes) pkts bytes target prot opt in out source destination Chain SSH_WHITELIST (1 references) pkts bytes target prot opt in out source destination 0 0 ACCEPT 0 -- any any jan.bude.lan anywhere recent: REMOVE name: SSH side: source server:~# cat /proc/net/ipt_recent/SSH src=140.211.166.4 ttl: 52 last_seen: 5801735 oldest_pkt: 2 5787039, 5801735