I didn't realise it was a clearos issue until I was going to make a post about it and saw this it did seem weird it started to happen recently but this makes sense as my internet on two of my clients servers drop out frequently and the server could always connect to the internet again but has to restart networking or restart the server to work again.
Thanks for the update Peter I'll monitor this and update.
Unfortunately this wouldn't solve the issue as port 81 would still be used via the firewall it would need to be a different port. I think the easiest solution is just expose 81 when a client needs to re-download their certificates to that particular server and then disable it at all other times.
That seems to work. However that can be a slight problem. We have several virtual machines running on a data centre and sometimes they need to share IP addresses.
The servers port to access it remotely is 810 but I have kept it's original port as 81 via iptables using port forwarding on the data centre server. This seemed to work and was fine for a very long time until the 6.5 update, is this how it needs to be from now on or is there a way to change clearos's port to not use port 81 as a base?