You can work top down, starting with the application layer (are other apps working?), or bottom up, are the problems caused by media connections or power to a device. Experienced troubleshooters will often begin at the layer indicated by the symptoms of a particular problem, this is called divide and conquer. In addition to this you could troubleshoot through trail and error or substitution.
- ipconfig shows the IP configuration.
- ping tests the network layer connectivity between devices.
- tracert tests connectivity and displays each hop.
- netstat shows current TCP/IP network connections to the device and protocol statistics.
- nslookup queries the configured name serve for DNS information.
LANs today often represent the logical grouping of hosts for a single organization. Network administrators typically refer to the network they maintain in their building(s) as a LAN or a private intranet. LANs support high data transfer rates over Ethernet or wireless protocols in a smaller geographic area.
A wide-area-network (WAN) provides relatively lower data transfer rates over a larger geographical area. These connectivities can be symmetric or assymetric. An assymetric connection typically has a faster download speed than upload speed. Symmetric connections on the other hand provide the same upload an download speed.
These are some WAN connections:
- A point-to-point (PPP) connection provides a specific dedicated path through the TSP network to connect two LANs over large distances.
- A circuit-switched WAN connection allows the client to create and close connections over the TSP network (uses the entire connection), operates lke a phone call - an example is ISDN.
- A packet-switched WAN connection allows multiple clients to share a single connection (uses a virtual circuit). An example is Frame Relay.