You were exposed to iptables in your OPS235 course. You should refer to those notes or find and use documentation to learn how to complete these tasks. You can also ask your professor or lab assistant during the lab for help when using iptables. Some basic iptables commands are provided in this lab for reference, but it is also essential that you know how to obtain help (man pages and online) in order to become self-reliant.

{{Admon/important |firewalld|In this lab we will be using ''iptables'', '''<u>not</u>''' ''firewalld''. Although both can be used at the same time, that would be too advantaged that this point of learning Linux network administration.<br><br>In the first labs, '''Prep for labs''', you should have disabled and stopped the firewalld service: [http://zenit.senecac.on.ca/wiki/index.php/OPS335_Installation_Lab#Using_iptables Prep for Labs].<br><br>You can also check the status of the firewalld service by issuing the '''systemctl''' command. You can also check if the firewalld service is running by issuing '''iptables -L''' and noting a high volume of unexpected output (i.e. "a strange result").