Interface Number Is Changed After Reboot Using the Route Command with the IF Parameter (263093)



The information in this article applies to:

  • Microsoft Windows NT Server 4.0 Terminal Server Edition
  • Microsoft Windows 2000 Server
  • Microsoft Windows 2000 Advanced Server
  • Microsoft Windows 2000 Professional
  • Microsoft Windows NT Server 4.0
  • Microsoft Windows NT Workstation 4.0
  • Microsoft Windows NT Server, Enterprise Edition 4.0

This article was previously published under Q263093

SYMPTOMS

After you enter a persistent route on your multi-homed computer where both network adapters are on the same subnet, the route either disappears or is assigned to a different network adapter on reboot.

When the IP stack initializes the stack on startup, Windows NT and Windows 2000 automatically create the default route to the 10.0.0.0 network.

For example, to observe this behavior you can configure two network adapters by using the following configuration information:

10.10.10.2 mask 255.255.255.0 gateway 10.10.10.4
10.10.10.5 mask 255.255.255.0

At a command prompt, type route -p add 10.0.0.0 mask 255.255.255.0 10.10.10.4 IF 2, and then press ENTER.

This is an example of the output of a route print command before a reboot:
===========================================================================
Interface List
0x1 ........................... MS TCP Loopback interface
0x2 ...00 00 f8 04 18 df ...... Intel DC21140 PCI Fast Ethernet Adapter
0x3000004 ...00 d0 b7 48 34 2e ...... Intel(R) PRO Adapter
===========================================================================
===========================================================================
Active Routes:
Network Destination        Netmask          Gateway       Interface  Metric
          0.0.0.0          0.0.0.0       10.10.10.4      10.10.10.5	  1
         10.0.0.0    255.255.255.0       10.10.10.4      10.10.10.2	  1
       10.10.10.0    255.255.255.0       10.10.10.2      10.10.10.2	  1
       10.10.10.0    255.255.255.0       10.10.10.5      10.10.10.5	  1
       10.10.10.2  255.255.255.255        127.0.0.1       127.0.0.1	  1
       10.10.10.5  255.255.255.255        127.0.0.1       127.0.0.1	  1
   10.255.255.255  255.255.255.255       10.10.10.2      10.10.10.2	  1
   10.255.255.255  255.255.255.255       10.10.10.5      10.10.10.5	  1
        127.0.0.0        255.0.0.0        127.0.0.1       127.0.0.1	  1
        224.0.0.0        224.0.0.0       10.10.10.2      10.10.10.2	  1
        224.0.0.0        224.0.0.0       10.10.10.5      10.10.10.5	  1
  255.255.255.255  255.255.255.255       10.10.10.2      10.10.10.2	  1
Default Gateway:        10.10.10.4
===========================================================================
Persistent Routes:
  Network Address          Netmask  Gateway Address  Metric
         10.0.0.0    255.255.255.0       10.10.10.4       1
				
NOTE: The preceding 10.0.0.0 network is associated with the 10.10.10.2 network adapter.

This is an example of the output of the route print command after a reboot:
===========================================================================
Interface List
0x1 ........................... MS TCP Loopback interface
0x2 ...00 d0 b7 48 34 2e ...... Intel(R) PRO Adapter
0x3 ...00 00 f8 04 18 df ...... Intel DC21140 PCI Fast Ethernet Adapter
===========================================================================
===========================================================================
Active Routes:
Network Destination        Netmask          Gateway       Interface  Metric
          0.0.0.0          0.0.0.0       10.10.10.4      10.10.10.5	  1
         10.0.0.0    255.255.255.0       10.10.10.4      10.10.10.5	  1
       10.10.10.0    255.255.255.0       10.10.10.2      10.10.10.2	  1
       10.10.10.2  255.255.255.255        127.0.0.1       127.0.0.1	  1
       10.10.10.5  255.255.255.255        127.0.0.1       127.0.0.1	  1
   10.255.255.255  255.255.255.255       10.10.10.2      10.10.10.2	  1
   10.255.255.255  255.255.255.255       10.10.10.5      10.10.10.5	  1
        127.0.0.0        255.0.0.0        127.0.0.1       127.0.0.1	  1
        224.0.0.0        224.0.0.0       10.10.10.2      10.10.10.2	  1
        224.0.0.0        224.0.0.0       10.10.10.5      10.10.10.5	  1
  255.255.255.255  255.255.255.255       10.10.10.5      10.10.10.5	  1
Default Gateway:        10.10.10.4
===========================================================================
Persistent Routes:
  Network Address          Netmask  Gateway Address  Metric
         10.0.0.0    255.255.255.0       10.10.10.4       1
				
Note that the preceding 10.0.0.0 network is now associated with the 10.10.10.5 network adapter.

CAUSE

This behavior can occur with a multi-homed computer where the IP addresses are all on the same network. When the IP stack initializes the stack during startup, Windows automatically creates the default route to the 10.0.0.0 network.

STATUS

This behavior is by design.

Modification Type:MajorLast Reviewed:6/30/2004
Keywords:kbenv kbnetwork kbprb KB263093