Internet Debug

I would like to devote a post to explaining basic debug methods for internet issues,
First of all I want to explain my approach to the process itself, I believe that in order to solve the problem we have to first understand why it occurs
Then find a solution, and most important try to avoid this in the future.

Slow / unstable connection or complete disconnections

Often an issue like this comes from a user uses a specific service that does not work properly
Most of my cases was regarding VOIP or VPN (the most sensitive connection types).
After eliminating the station by checking another one (or few to be sure) I'll start with
Usually this type of problems occurs as a result of Packet loss or latency on the path a packet travels.
to verify whether it's the case I would use a trace route to both sides illustrating the path,
from the trace output we can learn if there is latency (the hop starting exponential growth is most likely the cause)
let's say the trace did not show anything and the time it took for the packet to reach the end was reasonable
then I will try to ping each hop to verify if I get any packet loss, there is  – it's the problem and the solution is checking this device (and one before him)
there is none – look for other causes, I will look for Bandwidth overload or system resources of the gateway (Router / FW)
if all fails, every test show perfect results and the issue still persists consult with the destination for same tests on the other side.

To try and avoid the issue in the future I would most likely implement QOS when configured properly manages to overcome this type of an issue

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