So I recently came across a similar scenario that I have listed below and would like to know how to troubleshoot.

So let's say we have a scenario where a router has one of it's links congested because say that link is connected to a server which is being patched and therefore the link is getting overloaded which is causing problems or slowness of that link and also the server itself is not able to say use it's services properly.

Now how do I go about troubleshooting this issue if-

• if I have access to the router(ssh access) and have no idea that the issue is being caused by a server being patched (say I want to look at which link is getting saturated).

• if I do not have access to the router at all but have access to say a firewall (like checkpoint,Cisco ASA or something) and say I could look at the logs or something.