How to resolve unexplained WAN interface disconnects
I was having a frustrating issue with my 2.1 pfSense installation.
Periodically, the WAN would stop working and trigger a ripple which basically caused all interfaces–LAN and two VPN clients--to stop working. And I would have to restart all the interfaces manually or reboot pfSense.
I came across this post http://forum.pfsense.org/index.php/topic,17243.msg89348.html#msg89348 from a few years back, and following BennTech's instructions I set up a cron job that pings external servers. If the pings fail once, the script restarts the WAN interface. If they fail twice it reboots pfSense.
So far, pinging periodically has actually kept the WAN from failing. In the log written by the script, the WAN interface has restarted once since I started the cron job four days ago. I used to have the WAN failing issue multiple times a day.
When this happens, are any errors logged either at the console or in your system log? Are your interfaces two separate physical NICs or a dual port card? What driver is it using?
I was having an issue where my WAN interface would not stay up. I switched the WAN interface from em5 to em0 and found the problem was resolved. Every other time I've plugged anything into em5, same result. My issue seems to have been simply hardware related.
Maybe swap interface assignments and see if you get the same result on the the same NIC. If so, it's most likely hardware related. If the problem moves to the WAN interface on the new NIC, the problem is probably generated by a conflict between the pf box and the router/modem, or some other ISP setting.
At least, that sounds logical to me! : )