Configuration manual

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Nortel Business Secure Router 252 Configuration — Advanced
Appendix B
Triangle Route
The Ideal Setup
When the firewall is on, your Business Secure Router acts as a secure gateway
between your LAN and the Internet. In an ideal network topology, all incoming
and outgoing network traffic passes through the Business Secure Router to protect
your LAN against attacks.
Figure 129 Ideal Setup
The Triangle Route Problem
You can have more than one connection to the Internet (through one or more
ISPs). If an alternate gateway is on the LAN (and its IP address is in the same
subnet as the Business Secure Router LAN IP address), the triangle route (also
called asymmetrical route) problem can occur. The steps below describe the
triangle route problem.
A traffic route is a path for sending or receiving data packets between two
Ethernet devices. Some companies have more than one alternate route to one or
more ISPs. If the LAN and ISPs are in the same subnet, the triangle route problem
can occur. The steps below describe the triangle route problem.
Business Secure Router