I have a Cisco 1841 router with a DSL module card inserted. The router acts as a VPN via a DSL line to our HQ. I've noticed over the last 2 weeks the VPN line drops and sometimes comes back again. In some cases it doesn't so I get a user at that site to reboot the router. At first I though it was our DSL line, but today I noticed the line went down and came back up for a short while, so I managed to access the router and do a show version and the router said it had been up only 2 minutes, does this mean the router actually rebooted and it's not the DSL line after all?
If so how can I diagnose the problem?
The IOS version is c1814-advsecurityk9-mz.124-17.bin