Hello,

I would like to allow all that is possible to allow for accurate machine with a known IP.

#iptables -A INPUT -s xx.yyy.zzz.aa -j ACCEPT
#iptables -A OUTPUT -s xx.yyy.zzz.aa -j ACCEPT


... But I feel like it's not. Obviously I'm not sure of anything. Can you confirm / deny whether the commands above are likely to do what I believe they do, and how else should I do?

Thank you.

Two things I would change... -A appends the rules to the end of the list, meaning a previous rule could drop the traffic before it is "allowed" by your rule. -I inserts the rule to the top of the list making it the first rule processed (be careful not to "INSERT" rules later that could drop the traffic again).

Also, add the -p tcp to define the type of traffic you are looking for.

One last thought, since there is not much information detailing the setup and location of aa.yyy.zzz.aa in relation to your network, and I'm not sure the direction the traffic is flowing here, but one of these might need the -s changed to a -d for destination (probably the OUTPUT statement by my logic).