There is not "Enable IP routing"
If "Enable IP routing" is not an option in your Routing and Remote Access console, then you may need to install and configure the Routing and Remote Access service on your Windows 2003 Server. Here are some steps that you can follow:
1. On your Windows 2003 Server, go to Control Panel > Add or Remove Programs.
2. Click on Add/Remove Windows Components.
3. Select "Networking Services" and then click Details.
4. Check the "Routing and Remote Access" box and then click OK.
5. Click Next to continue installation.
6. Once installation is complete, open the Routing and Remote Access console.
7. Navigate to the IP Routing node, and then to the General node.
8. Right-click on the General node and select Properties from the context menu.
9. Select the option to "Enable IP routing" and then click OK.
After you have enabled IP routing, you can configure the IP Address Pool and assign static IP addresses to your VPN users by following the steps I provided earlier:
1. Open the Routing and Remote Access console on your Windows 2003 Server.
2. Navigate to the IP Routing node, and then to the General node.
3. Right-click on the General node and select New Routing Protocol.
4. Select Static IP Address Pool from the list of available routing protocols.
5. Provide a name for the static IP address pool, and then specify the range of IP addresses that you want to use.
6. Click OK to create the static IP address pool.
7. Open the Active Directory Users and Computers console on your Windows 2003 Server.
8. Navigate to the user account that you want to assign a static IP address to.
9. Right-click on the user account and select Properties from the context menu.
10. Select the Dial-in tab, and then select Assign a Static IP Address.
11. Enter the IP address that you want to assign to the user, and then click Apply to save the changes.
Remember, the IP address you specify for your VPN users must be within the range of IP addresses that you configured in the IP Address Pool.