Point to point virtual Ethernet IP address conflicts

IBM iSeries Integrated Server Support uses IP addresses in the range of 192.168.x.y for the integrated server's point to point Ethernet network. By default, the actual addresses are selected by the i5/OS Install Windows server (INSWNTSVR) command. For details and examples, see Assign point to point virtual Ethernet IP addresses . Depending on your network, there might be conflicts with addresses that are already in use. To avoid potential conflicts you can use the VRTPTPPORT parameter for an Integrated xSeries® Server or the Integrated xSeries Adapter attached xSeries server.

If a conflict requires you to change the addresses, you must ensure that the point to point virtual Ethernet occupies its own subnet on i5/OS. The subnet mask that is used is 255.255.255.0. To ensure that the point to point virtual Ethernet is on its own subnet, use IP addresses of the form a.b.x.y, where a.b.x is the same value for both sides of the point to point virtual Ethernet. Also verify that the value of a.b.x is unique on your network.

To change the point to point virtual Ethernet addresses because of a conflict, take the following action.

  1. At the i5/OS console, enter the command DSPNWSD NWSD(name) OPTION (*PORTS). Make a note of the Attached line for the port number *VRTETHPTP, which is also known as the line description.
  2. Use the Configure TCP (CFGTCP) command and option 1 to display the TCP interfaces. Make a note of the IP address and the subnet mask associated with the line description that you found in step 1.
Note:
An IP address entered at the Windows console for the point to point virtual Ethernet overrides the values that are set in the NWSD for the TCPPRTCFG parameter *VRTETHPTP.
  1. Click on Start—>Settings–>Control Panel, then Network and Dial-up Connections.
  2. Start of changeRight-click the correct Local Area Connection for the point to point virtual Ethernet and select Properties from the menu.End of change
  3. Select TCP/IP Protocol from the list of installed protocols and press the Properties button to display the TCP/IP properties.
  4. Change the IP address for the new value that you have selected.
  5. Click OK, then Close to close the application.
  6. Shut down the integrated Windows server without doing a restart.
  7. On i5/OS, vary off the NWSD.
  8. Use the Remove TCP/IP interface (RMVTCPIFC) command with the IP address you recorded in step 2.
  9. Use the Add TCP/IP interface (ADDTCPIFC) command to add the new interface. Use the IP address that you selected for the i5/OS side of the point to point virtual Ethernet. You also need to enter the subnet mask and line description that you recorded in steps 1 and 2.
  10. On the i5/OS command line, type CHGNWSD NWSD(name), and press F4.
    1. Page down to the section labeled TCP/IP port configuration.
    2. Change the IP address in the Internet address field for the port *VRTETHPTP to the value that you used in step 3. Press Enter for the change to take effect.
    3. Vary on the NWSD.
    Note:
    Start of changeIf you are installing multiple servers, to avoid further conflicts, assign point to point virtual Ethernet IP addresses (see Assign point to point virtual Ethernet IP addresses) instead of letting the INSWNTSVR command generate them. The Virtual PTP Ethernet port parameter allows you to enter IP addresses that you know to be unique on your system.End of change