My server is a FreeBSD system, I run nginx on it to proxy user requests to another real server. My problem is I can't visit my freebsd server after a while. The server is in another place, so I have to go to fix it. When the problem happens, the server can't ping another address, it can't use networks, if I reboot it and restart nginx, everything becomes normal. But after a while, it can't be visited again. I am not quite familiar with freebsd, so anyone can't help to find out the possible reason?
Also check out your firewall, I had some problems with a server not forgetting about connections for a few hours. Eventually it would fill up its allotted connections and just reject everything else. If I waited it would come back. In the end I just had to disable connection tracking.