229Nortel Business Secure Router 222 Configuration — AdvancedAppendix BTriangle RouteThe Ideal SetupWhen the firewall is on, your Business Secure Router acts as a secure gatewaybetween your LAN and the Internet. In an ideal network topology, all incomingand outgoing network traffic passes through the Business Secure Router to protectyour LAN against attacks.Figure 133 Ideal SetupThe Triangle Route ProblemYou can have more than one connection to the Internet (through one or moreISPs). If an alternate gateway is on the LAN (and its IP address is in the samesubnet as the Business Secure Router LAN IP address), the triangle route (alsocalled asymmetrical route) problem can occur. The steps below describe thetriangle route problem.A traffic route is a path for sending or receiving data packets between twoEthernet devices. Some companies have more than one alternate route to one ormore ISPs. If the LAN and ISP are in the same subnet, the triangle route problemcan occur. The steps below describe the triangle route problem.Business Secure Router
