Installing and Administering Internet Services

380 Chapter 12
Troubleshooting Internet Services
Diagnosing Repeater and Gateway Problems
Diagnosing Repeater and Gateway
Problems
If you are using a repeater and hosts on either side of the repeater are
having difficulty communicating with each other, a repeater subsystem
failure may have occurred. In the illustration below, all of the systems on
side A are able to communicate with one another. All the systems on side
B are able to communicate with each other. If communication is cut from
side A to side B, the repeater subsystem is suspect for causing the fault,
since it is the medium by which side A and side B communicate.
Figure 12-1 Troubleshooting Networks that Use Repeaters
The same concept holds for communication through a gateway. If you
suspect a gateway problem, try the following procedures:
• To determine if you are set up to communicate with the desired node,
execute the following:
netstat -r
• To obtain routing statistics, execute the following:
netstat -rs
The statistics could indicate a bad route, suggesting a problem with a
gateway node. If so,
• Check with the node manager of the gateway node to ascertain proper
operation of the gateway.
• You can detect problems with the X.25 line by the number of errors
shown when you execute the following:
Repeater MAU
A
LAN
Repeater MAU
B
Repeater
Unit
computer computer computer computer
Repeater AUI
cable A
Repeater AUI
cable B
Side A Side B