$ sudo iptables -L
Chain INPUT (policy DROP)
target prot opt source destination
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED /* allow inbound traffic for established and related connections */
fail2ban-ssh tcp -- anywhere anywhere multiport dports ssh
ACCEPT tcp -- anywhere anywhere tcp dpt:ssh /* allow SSH to this host from anywhere */
ACCEPT udp -- anywhere anywhere udp dpt:route /* allow incoming RIP on the internal interface */
ACCEPT all -- localhost localhost /* allow any local-only traffic */
ACCEPT ipv6 -- tserv2.ash1.he.net anywhere /* allow IPv6 tunnel traffic from HE */
ACCEPT icmp -- anywhere anywhere /* allow ICMP traffic to this host from anywhere */</p><p> Chain FORWARD (policy DROP)
target prot opt source destination
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED /* allow inbound traffic for established and related connections */
ACCEPT all -- anywhere anywhere /* allow all Internet bound traffic from the internal network */
ACCEPT icmp -- anywhere anywhere /* forward any ICMP traffic */</p><p> Chain OUTPUT (policy ACCEPT)
target prot opt source destination</p><p> Chain fail2ban-ssh (1 references)
target prot opt source destination
RETURN all -- anywhere anywhere

$ sudo iptables -A INPUT -p tcp -m tcp --dport 22 -m comment --comment "allow SSH to this host from anywhere" -j ACCEPT

$ sudo iptables -L</p><p>ACCEPT tcp -- anywhere anywhere tcp dpt:ssh /* allow SSH to this host from anywhere */