Ping the loopback interface on your server

Ping the loopback interface to verify that your TCP/IP software is installed and working properly.

You can perform the test without being connected to a physical line or network.

i5/OS™ reserves the IP address 127.0.0.1, the host name LOOPBACK, and the line description value of *LOOPBACK for verifying the software. Similarly for IPv6, i5/OS reserves the IP address ::1 and the line description *LOOPBACK for this purpose. The IPv6 loopback interface does not have a corresponding host name because the local host tables do not currently support IPv6 addresses. However, you can use a Domain Name System (DNS) to store the IPv6 host name instead of using the local host table.

To ping the loopback interface on your server to troubleshoot the problem, follow these steps:

  1. In iSeries™ Navigator, expand your iSeries server > Network.
  2. Right-click TCP/IP Configuration, and select Utilities > Ping.
  3. Specify the loopback interface IP address or host name. If you are testing by using the host name, you must select the Protocol for host names.
  4. Click Ping Now to send the Ping. View the responses to your Ping in the list of results.
  5. Failures might indicate these problems:
    Problem Recovery
    The local host table does not have an entry for the LOOPBACK host name and IP address of 127.0.0.1. Add the entry to the host table. This is only relevant for IPv4 because host tables do not currently support IPv6. To verify the host table entries, follow these steps:
    1. In iSeries Navigator, expand your iSeries server > Network.
    2. Right-click TCP/IP Configuration and select Host Table.
    3. Verify that the host table contains an entry for the LOOPBACK host name and IP address 127.0.0.1.
    The loopback interface is not active. To activate the loopback interface:
    • For IPv4:
      1. In iSeries Navigator, expand your iSeries server > Network > TCP/IP Configuration > IPv4 > Interfaces.
      2. In the right pane, right-click the loopback interface (127.0.0.1) and select Start.
    • For IPv6:
      1. In iSeries Navigator, expand your Series server > Network > TCP/IP Configuration > IPv6 > Interfaces.
      2. In the right pane, right-click the loopback interface (::1) and select Start.
    TCP/IP has not been started. Start TCP/IP.
Parent topic: Ping from iSeries Navigator
Related reference
Common error messages