To enable access to the SSH server in IPTables, you must add a rule:
sudo iptables -A INPUT -p tcp --dport 22 -j ACCEPT
To open only a particular network, for example 192.168.0.0/24:
sudo iptables -A INPUT -s 192.168.0.0/24 -p tcp --dport 22 -j ACCEPT
You can also restrict access by the IP configuration of the SSH itself.
To remove a rule, we’ll specify the same command, replacing -A with -D, for example:
sudo iptables -D INPUT -p tcp --dport 22 -j ACCEPT
To view the list of rules, use the command:
sudo iptables -nvL
See also:
Installing and Configuring SSH
Configuring IPTables