Installing and Administering Internet Services

376 Chapter 12

Troubleshooting Internet Services

Characterizing the Problem

It is important to ask questions when you are trying to characterize a

problem. Start with global questions and gradually get more speciﬁc.

Depending on the response, ask another series of questions until you

have enough information to understand exactly what happened. Key

questions to ask are as follows:

• Does the problem seem isolated to one user or program? Can the

problem be reproduced? Did the problem occur under any of the

following circumstances:

• When running a program?

• When issuing a command?

• When using a nodal management utility?

• When transmitting data?

• Does the problem affect all users? The entire node? Has anything

changed recently? The possibilities are as follows:

• New software and hardware installation?

• Same hardware but changes to the software. Has the

conﬁguration ﬁle been modiﬁed? Has the HP-UX conﬁguration

been changed?

• Same software but changes to the hardware. Do you suspect

hardware or software?

It is often difﬁcult to determine whether the problem is hardware-related

or software-related. The symptoms of the problem that indicate you

should suspect the hardware are as follows:

• Intermittent errors.

• Network-wide problems after no change in software.

• Link-level errors, from logging subsystem, logged to the console.

• Data corruption—link-level trace that shows that data is sent

without error but is corrupt or lost at the receiver.

• Red light on the LAN card is lit, or yellow light on the X.25/800 card

is lit.