Domain Controllers Unable to Communicate Over IPX Token-Ring WAN

MORE INFORMATION

• Make sure the routers are NOT filtering any type 20 (Hex 14) WAN broadcast IPX packets on the WAN link.
• Make sure NETBIOS is enabled on the routers.
• Make sure that the SAP Agent service is running on both the PDC and BDC.
• The two DCs may be trying to communicate at a bigger frame size (4096 bytes). The size of these packets going over a WAN link may be slow enough for their connection to time-out. Use regedt32 and add a REG_DWORD value of 576 to RouterMTU. It should be added to:
  
  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NwlnkNb\Paramet
  
  This limits the size of the NETBIOS over NWLink IPX packets to 576 bytes. You can fine tune this setting to achieve optimal throughput. The ACC Nile routers have a default value for their maximum transmission unit of 576 bytes. This can be modified using the "Set IPX network MTU" command and can range from 576 bytes to 4491 bytes on Token-Ring networks.
• Make sure the IPX net numbers and frame types for the DCs match the network segments on which they are located, especially if you have initially configured and tested them on the same segment before moving the BDC across the WAN link.