I am having a problem with a site where I have configured two identical Cisco 1720 routers with T1 CSU/DSU WIC's. The T1 goes up and down about every two minutes. When the serial side is up, we can ping the other sides hosts and get to the resources. When the line goes down, we get destination unreachable. Verizon tested the line and says that it tested fine and is the hardware. Question: Could a router mis-configuration cause this type of problem?
If needed, I can post the router configs.