---
author: James Wen
hints:
  - Using 'tcpdump' on the Gitlab server is a great way to monitor outgoing and incoming traffic of all kinds. You can filter for source and destination ports and ip addresses.
  - Using 'ping' to try and reach the Gitlab server is a great way to see whether the server can resolve any kinds of traffic. But beware, ping uses icmp protocol!
  - Using dns lookup tools like 'dig' or 'nslookup' are great ways to find whether a hostname or IP address is resolvable.
  - Using 'curl' is a great way to get more explicit HTTP info about endpoints.
  - I think someone on the security team mentioned something recently about changing firewall rules on all servers...
  - One of the most commonly utilized Linux utilities for network control is 'iptables'. Super powerful tool!
description: Your Gitlab instance is no longer reachable! You seem to no longer be able to access the Gitlab instance.
introduction: You are running Gitlab. You're oncall for it.
solution: Just flush those iptable rules! Or, if you want to be more surgical, here's how you can disable that specific rule

---
author: James Wen
hints:
  - Using 'tcpdump' on the Gitlab server is a great way to monitor outgoing and incoming traffic of all kinds. You can filter for source and destination ports and ip addresses.
  - Using 'ping' to try and reach the Gitlab server is a great way to see whether the server can resolve any kinds of traffic. But beware, ping uses icmp protocol!
  - Using dns lookup tools like 'dig' or 'nslookup' are great ways to find whether a hostname or IP address is resolvable.
  - Using 'curl' is a great way to get more explicit HTTP info about endpoints.
  - I think someone on the security team mentioned something recently about changing firewall rules on all servers...
  - One of the most commonly utilized Linux utilities for network control is 'iptables'. Super powerful tool!
description: You are running your company's public Gitlab instance. You're also currently oncall for it. Let's see how you handle some network issues.
introduction: Your Gitlab instance is no longer reachable! You seem to no longer be able to access the Gitlab instance via browser or curl? Let's get to fixing it!
solution: One way to fix the issue would be to just flush those iptable rules via 'sudo iptables -F'. However, this would also flush and delete all the other existing iptables rules. The recommended fix would be to remove that specific rule. You can do this by running 'sudo iptables -D <rule specifics>'. Check out the module 'resolve' script for a detailed example.

Update description, solution, and intro for sample network module
Update description, solution, and intro for sample network module
