NethServer release 7.4.1708 (Final)
Sorry for bad English.
I have a problem.
The problem is that the server stops the internal network. It will only be good after restarting.
Internal network downtime is always generated while using the Internet. No matter which workstation.
It has been installed for a year, the error is 3 days.
I do not know what to look for, because I’m beyond everything.