10.14 The uname Command

10.15 Basic Network Problem Determination

When a user informs you that a certain system cannot be accessed, check for various network problems. Typically, you will go through these TCP/IP problem determination topics using whichever is applicable to your environment:

• Communication Problems

• Name Resolution Problems

• Routing Problems

• Problems with System Resource Controller (SRC) Support

• Telnet or rlogin Problems

• Configuration Problems

• Common Problems with Network Interfaces

• Problems with Packet Delivery

• Problems with Dynamic Host Configuration Protocol (DHCP)

However, there are other consideration outside the network area that you should check also:

• The server system may be down.

  This will usually reveal itself when you check for communication problems. The ping command will lead you to the problem system. The whole system may be down or the network interface may be down.

• The paging space may be full.

  If a user has logged in, this will be fairly obvious as there is usually a system message stating not enough paging space or not enough memory. However, if a user is trying to telnet or ftp to the system, there will be time outs as the system cannot create additional processes, or the system may be busy killing processes.

• A file system may be full.

  If the user can access the system, but there are problems with certain functions, you should check all areas in the system. If the user cannot start the Web Based System Manager (WSM), the /tmp filesystem may be full.

• A file system may not have been mounted.

  Usually, the user will mention losing all his files.

Not all problems are caused by the network and the network function. Make sure you understand your user's problem before concluding that it is a network problem.

10.16 Quiz