My server restarted three weeks ago, and ever since then, we have had some issues, such as a much slower TTFB when accessing the website. It went from less than a second to now more than 5 seconds. I tried to check the etc/resolv.conf in case the nameservers changed and caused the DNS lookups to be slower than before which could maybe cause that issue, however even after replacing the resolv.conf set to what it was before the restart it didn't fix this.
Another issue that I have had since the restart involves a VPN that is used on the server being disconnected everytime ssh is used to connect to the server, this is covered in a bit more detail here.
I know this is a very broad question and I apologise, I'm just trying to figure out what sort of configurations might have changed on my server when it restarted, any insight that might lead me in the right direction would be greatly appreciated, as I am new to networking.
I am mostly looking for clues at least on what might have changed relating to maybe DNS lookups and IP routing configurations that could be influencing the VPN when I use ssh to connect to the server.
For now, I have results from the commands: "iptables -L INPUT", "route -n", and "sudo ufw status" but I am not entirely sure what to make of these, nor what is safe to share here, but it would be great if someone more experienced could tell me if one of these commands, is what I need to be looking at.
Any tips on how to improve this question is also appreciated.
