How to Use Static Routes with Routing and Remote Access Service

ID: Q178993

The information in this article applies to:

Microsoft Windows NT Server version 4.0
Microsoft Routing and Remote Access Service Update for Windows NT Server 4.0

SUMMARY

The information in this article explains how to add static routes to a computer running Windows NT Server and the Routing and Remote Access Service (RRAS) Update, so that it can route packets to a remote network. The information in this article only pertains to those environments where no routing protocols are configured, such as Routing Information Protocol (RIP) or Open Shortest Path First (OSPF).

MORE INFORMATION

Depending upon the specific scenario, static routes may not be the most efficient method of achieving IP routing. However, in smaller environments where there are few networks, it can be less overhead than using a routing protocol.

NOTE: The following steps assume that RRAS is installed, the Dial-on-Demand (DOD) interfaces are properly configured, and connections are successful between the two RRAS servers.

To add a static route, perform the following steps on both servers:

Click Start, point to Programs, point to Administrative Tools, and click Routing and RAS Admin.

Double-click IP Routing to expand that object.

Right-click Static Routes and click Add static route.

The following information will be necessary to add a static route:

Destination (Network)
Network Mask
Gateway (address)
Metric
Interface

There are several reasons for wanting to add a static route to your configuration and there are several configuration issues that can alter what you add in the parameters above. Several scenarios are shown below to help you configure your static routes, but these scenarios are not intended to be a complete list of possibilities.

Scenario One: A Simple LAN-to-LAN Environment


       RRAS(1) --- Modem -  -  - Modem --- RRAS(2)
      10.10.0.1                            10.20.0.1
          |                                    |
       LAN(1)                                LAN(2)
      10.10.0.0                            10.20.0.0

Network Interface Card (NIC) IP parameters on:

RRAS(1) <IP> 10.10.0.1, mask 255.255.0.0, no default gateway
RRAS(2) <IP> 10.20.0.1, mask 255.255.0.0, no default gateway

RRAS(1) has a DOD named "HELLO" that dials RRAS(2)
RRAS(2) has a DOD named "HELLO" that dials RRAS(1)

NOTE: The names of the DOD interfaces above are the same for convenience. For more information on how to name DOD interfaces, see the following article in the Microsoft Knowledge base:

ARTICLE-ID: Configuring Routing and Remote Access Dial-Up Interfaces
TITLE : Q159684

In this scenario, there are no other routers and the desired result is for IP packets on LAN(1) to be successfully routed to LAN(2) and vice versa. In this scenario, all computers on LAN(1) will define their default gateway address as 10.10.0.1 (RRAS(1) NIC) and all the computers on LAN(2) will define their default gateway address as 10.20.0.1 (RRAS(2) NIC). The table below shows the information that should be supplied to add the static routes for each RRAS router:


                            RRAS(1)   RRAS(2)
     Destination (Network)  0.0.0.0   0.0.0.0
     Network Mask           0.0.0.0   0.0.0.0
     Gateway (address)      1.1.1.1   1.1.1.1
     Metric                 1         1
     Interface              "HELLO"   "HELLO"

The destination address and network mask on both routers should be all zeroes, the gateway address should be all ones. The metric is unimportant in this scenario, setting it to one is sufficient. It is very important to choose the DOD interface in the drop down window that is configured to dial the remote location.

Scenario Two: A LAN-to-LAN Environment with One Other Router


Router(A)            RRAS(1) --- Modem -  -  - Modem ---  RRAS(2)
10.40.0.1  10.10.0.2      10.10.0.1                            10.20.0.1
    |        |                |                                     |
 LAN(4)       ---  LAN(1)  ---                                    LAN(2)
10.40.0.0        10.10.0.0                                      10.20.0.0

NIC IP parameters on:

RRAS(1) <IP> 10.10.0.1, mask 255.255.0.0, default gateway 10.10.0.2
RRAS(2) <IP> 10.20.0.1, mask 255.255.0.0, no default gateway

RRAS(1) has a DOD named "HELLO" that dials RRAS(2)
RRAS(2) has a DOD named "HELLO" that dials RRAS(1)

This scenario is used to describe a remote, or satellite, office connecting to the larger corporate network through a RRAS Server. Notice in this scenario that the IP configuration of the NIC on RRAS(1) now has a default gateway parameter. This means that the static route that is added to RRAS(1) will need to be different. Instead of adding a default gateway route of 0.0.0.0, a specific network route will need to be added to RRAS(1). The default gateway specified on the NIC will take care of any other routing that may be necessary. Also notice that because RRAS(2) has no other route in its environment, it can use the same route as in Scenario One above. The following table shows the information that should be supplied for each RRAS router:


                            RRAS(1)      RRAS(2)
     Destination (Network)  10.20.0.0    0.0.0.0
     Network Mask           255.255.0.0  0.0.0.0
     Gateway (address)      1.1.1.1      1.1.1.1
     Metric                 1            1
     Interface              "HELLO"      "HELLO"

Scenario Three: A LAN-to-LAN Environment with Multiple Routers


Router(A)        RRAS(1) --- Modem - - Modem --- RRAS(2)       Router(B)
10.10.0.2       10.10.0.1                        10.20.0.1       10.20.0.2
   |                |                                |                |
    ---- LAN(1) ----                                  ---- LAN(2) ----
       10.10.0.0                                         10.20.0.0

NIC IP parameters on:

RRAS(1) <IP> 10.10.0.1, mask 255.255.0.0, default gateway 10.10.0.2
RRAS(2) <IP> 10.20.0.1, mask 255.255.0.0, default gateway 10.20.0.2

RRAS(1) has a DOD named "HELLO" that dials RRAS(2)
RRAS(2) has a DOD named "HELLO" that dials RRAS(1)

The following scenario assumes that there are two office locations with multiple IP segments on each. The two offices are connecting through RRAS Servers. Notice in this scenario that the IP configurations of the RRAS NICs have default gateways configured. This means that the static routes that are added to each RRAS Server will have to be more specific. Instead of adding default gateway routes of 0.0.0.0, specific network routes will need to be added to both servers. The default gateway specified on the NIC will take care of any other routing that may be necessary. The following table shows the information that should be supplied for each RRAS router:


                            RRAS(1)       RRAS(2)
     Destination (Network)  10.20.0.0     10.10.0.0
     Network Mask           255.255.0.0   255.255.0.0
     Gateway (address)      1.1.1.1       1.1.1.1
     Metric                 1             1
     Interface              "HELLO"       "HELLO"

Scenario Four: Multiple RRAS Servers and Multiple Routers


Router(A)        RRAS(1) --- Modem ----- Modem --- RRAS(2)     Router(B)
10.10.0.2       10.10.0.1        |      /          10.20.0.1     10.20.0.2
   |                |            |     /               |                |
    ---- LAN(1) ----             |    /                 ---- LAN(2) ----
       10.10.0.0                 |   /                     10.20.0.0
                                 |  / 
                                 | / 
                                 |/ 
Router(C)        RRAS(3) --- Modem
10.30.0.2       10.30.0.1
   |                |
    ---- LAN(3) ----
       10.30.0.0

NIC IP parameters on:

RRAS(1) <IP> 10.10.0.1, mask 255.255.0.0, default gateway 10.10.0.2
RRAS(2) <IP> 10.20.0.1, mask 255.255.0.0, default gateway 10.20.0.2
RRAS(3) <IP> 10.30.0.1, mask 255.255.0.0, default gateway 10.30.0.2

RRAS(1) has a DOD named "HELLO1020" that dials RRAS(2)
has a DOD named "HELLO1030" that dials RRAS(3)

RRAS(2) has a DOD named "HELLO1020" that dials RRAS(1)
has a DOD named "HELLO2030" that dials RRAS(3)

RRAS(3) has a DOD named "HELLO1030" that dials RRAS(1)
has a DOD named "HELLO2030" that dials RRAS(2)

Notice that in this scenario, not only does each network have an additional router on it, but the RRAS Servers dial different DOD interfaces depending on where the packets need to be sent. This means that more than one static route will need to be added and that each of these static routes will need to be specific network routes. The following table shows the information that should be supplied for each RRAS router:


First static route     RRAS(1)      RRAS(2)      RRAS(3)
Destination (Network)  10.20.0.0    10.10.0.0    10.10.0.0
Network Mask           255.255.0.0  255.255.0.0  255.255.0.0
Gateway (address)      1.1.1.1      1.1.1.1      1.1.1.1
Metric                 1            1            1
Interface              HELLO1020    HELLO1020    HELLO1030

Second static route
Destination (Network)  10.30.0.0    10.30.0.0    10.20.0.0
Network Mask           255.255.0.0  255.255.0.0  255.255.0.0
Gateway (address)      1.1.1.1      1.1.1.1      1.1.1.1
Metric                 1            1            1
Interface              HELLO1030    HELLO2030    HELLO2030

Troubleshooting Static Routes

The following are some troubleshooting steps for static routes in a RRAS environment:

If the DOD connections cannot be made for some reason, the static routes will not function. The DOD connections and modem lines must be working before static routes over the DOD connections will work. Local routing will still function.

As with all routed environments, routers at each hop must have the correct routing information in order to get packets from one side of a network to the other. This means that adding static routes on one side may not be useful if the destination router has no route to get the packets back to the originating network.

Make certain the correct DOD interface for static routes to other networks is correctly identified. If packets are to be routed over a DOD connection, make sure to select the correct DOD interface when creating the static route. Selecting the NIC will not be sufficient to initiate a DOD connection.

Reinstallation of Windows NT Service Pack 3 over RRAS may be necessary on your server and can result in intermittent problems with connectivity, including routing of packets through static routes. If Service Pack 3 is reapplied over an RRAS installation, RRAS must be updated.


Keywords          : kbnetwork kbhowto nthowto ntnetserv kbinfo ntrouter NTSrv 
Version           : WinNT:4.0
Platform          : winnt 
Issue type        : kbinfo

Last Reviewed: January 29, 1999