Table of Contents

1. Challenge

   Verify that a firewall is running.

   You should already have iptables started and running. You can verify this with:

   # systemctl status iptables

2. Challenge

   Verify that the host listening on port 80.

   You'll want to verify that the host has a service listening on port 80. You can do so using the following command:

   # ss -lntp | grep :80

   You should see that port 80 is listening for the httpd process.

3. Challenge

   Verify that port 80 is blocked, and add a rule to permit traffic coming from 10.0.1.11.

   From Client1 (10.0.1.11), try to curl 10.0.1.10:

   [cloud_user@ip-10-0-1-11 ~]$ curl 10.0.1.10

   You'll need to add a rule to permit the traffic:

   iptables -I INPUT -p tcp -s 10.0.1.11 --dport 80 -j ACCEPT

   Test from Client1 again, and also with Client2. If Client1 is successful and Client2 isn't, save your existing chain with:

   [root@ip-10-0-1-10 ~]# service iptables save