Lab
A Cloud Guru

Permitting and Blocking Traffic with the Firewall

In this hands-on lab, you will need to configure `Server1` (10.0.1.10) so that it only permits HTTP connections (port 80) from `Client1` (10.0.1.11).

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Path Info

Level

Intermediate

Duration

30m

Published

Nov 14, 2018

Challenge

Verify that a firewall is running.

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

# systemctl status iptables
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.
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

Author

A Cloud Guru

The Cloud Content team comprises subject matter experts hyper focused on services offered by the leading cloud vendors (AWS, GCP, and Azure), as well as cloud-related technologies such as Linux and DevOps. The team is thrilled to share their knowledge to help you build modern tech solutions from the ground up, secure and optimize your environments, and so much more!

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