A Microsoft Proxy Server computer should have only one IP default
gateway. The IP address of the default gateway should be configured on
the external network adapter card only.
This requirement is a result of the basic architecture of TCP/IP. Only
one default gateway must be defined on a host that resides on 2 or more
If the Proxy server is configured with more than one network interface, it
is connected to two networks that are by design non-connected.
A default gateway is a router that is supposed to be used for all
traffic that has no specific route. If you have two default-gateways,
the proxy server TCP/IP stack will assume that they lead to the same set
of networks. This will cause the proxy server to send Internet traffic
to the internal network, or internal traffic to the Internet.
Because no default gateway will be defined for the internal network, you must add static routes using the Route Add command. These routes can be made persistent by using the -p command switch.
For additional information on adding static routes to the routing table, see the following:
- Type route /? for additional command switches.
- See the following Microsoft Knowledge Base article:140859 TCP/IP Routing Basics for Windows NT
Article ID: 161380 - Last Review: Feb 19, 2002 - Revision: 1