Permitting and Blocking Traffic with the Firewall

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

# systemctl status iptables

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.

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