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AIX Version 4.3 Problem Solving Guide and Reference

Resolve Communication Adapter Problems

Determine if your communication adapter is the source of your network problems by:

Checking for Software Problems

  1. Use the netstat command to make sure there is a complete route from your machine to the target machine. For example:
    netstat -r

    The netstat command displays the status and various statistics of the network.

    The error no route to remote host available may indicate that there is not a complete route from your machine to the target or a machine on the route is down.

  2. Check for input and output errors. For example:
    netstat -i

    Input and output errors can be caused by bad cables or by bad packets sent from other machines to your machine. Input errors can also indicate that a packet was sent to an unknown protocol.

  3. Check if your machine needs more buffers allocated to networking. For example:
    netstat -m

    If a large amount of memory has been denied in the statistics listing, consider reconfiguring the number of memory buffers allocated to networking. You can find more information about tuning these types of parameters in AIX Versions 3.2 and 4 Performance Tuning Guide.

  4. Check for dropped connections. For example:
    netstat -s

    Look at the statistics on protocol layers. Dropped connections could indicate a problem with the network or with disconnected cables.

  5. Use the arp command to make sure you have the complete IP address for the target machine. For example:
    arp -a

    The arp command looks for the physical adapter address. This command might show an incomplete address. For example:

    ? ( at (incomplete)

    This could be due to an unplugged machine, a stray address with no machine at that particular address, or a hardware problem (such as a machine that connects and receives packets but is not able to send packets back).

  6. Look for errors on the adapter card. For example:
    netstat -v

    The netstat -v command shows statistics for the Ethernet, Token Ring, X.25, and 802.3 adapter device drivers. The command also shows network and error logging data for all device drivers active on an interface including: No Mbufs Errors , No Mbuf Extension Errors , and Packets Transmitted and Adapter Errors Detected .

Checking for Hardware Problems

To effectively test a network adapter, the adapter must not be figured on the network. Testing of the network adapter should be done from a standalone mode or by unconfiguring the adapter. Run diagnostics in either of two ways to verify that the adapter card is good:

Go back to Network Problems.

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