Installing and Administering Internet Services

Chapter 12 383

Troubleshooting Internet Services

Troubleshooting the Internet Services

When troubleshooting problems with the Internet Services, you need a

reference point to work from. For example, does the problem exist on the

remote system or on the local system? However, the terms “local” and

“remote” are limited in their description of complex communications,

such as when a local system logs onto a remote system and then the

remote system logs back onto the local system. At that point, which is the

local system and which is the remote system?

A better solution is to use the terms “client” and “server.” The term

“client” refers to a process that is requesting a service from another

process. The term “server” refers to a process or host that performs

operations requested by local or remote hosts that are running client

processes.

HP has implemented a “super-server” known as the internet daemon,

inetd. This program acts like a switchboard; that is, it listens for any

request and activates the appropriate server based on the request.

A typical network service consists of two co-operating programs. The

client program runs on the requesting system. The server program runs

on the system with which you want your system to communicate. The

client program initiates requests to communicate. The server program

accepts requests for communication. For example, the network service

rlogin is the client program that requests a login to a remote HP-UX or

UNIX system. When the request to log in is received on the remote host

by inetd, inetd invokes the server program for rlogin (called

rlogind) to handle the service request.

Error Messages

The error messages generated by a service as seen on the client can be

generated by the client or the server. Error messages from the client

occur before a connection is completely established. Error messages from

the server occur after a connection is completely established.

Whenever you receive an error message, follow the corrective action

supplied in the man page for that service. The error message is preceded

by the name of the service. Table 12-2 shows the appropriate man page to

consult for a description of the error messages: