Diagnosing Routing issues

There are different approaches for resolution depending on the connection issue scenario. Lets imagine we have a central office that has two versatility field facilities. Central office has a t1 backbone with two servers and sixteen clients. Both field offices are connected with static dsl with one server and five clients. Network connectivity for LAN is configured with a static nat table over VPN. All locations are able to connect to the internet but there is a problem with internal communications between servers. As the network engineer I would start by identifying the issue first hand and replicate. Once the issue is replicated such as expected file replication service (FRS) not replicating across servers I would then run a quick series of tests:

      • ping gateway ip
      • ping server ip
      • ping external IP
      • trace route IP
      • reboot to clear cache
      • check router logs
      • verify router configuration

Most likely the issue would be one of two things: a possible issue with router NAT tables which a simple reboot would resolve, or, an error in VPN communications. However, rare scenarios in the I.T. world occur and there could be a issue with DNS. Albeit, the best tool for diagnostics: a ping and trace route utility.