The IP Office system acts as the default gateway for its DHCP clients. You can also specify the IP Office as the default gateway statically addressed devices on the same subnet as the IP Office. When those clients and devices want to send data to an IP address on a different subnet, they will send that data to the IP Office system for onward routing.

• IPv4 Static Routes

  For IPv4 traffic, the IP Office can use the System > IP Route configuration settings to determine where to forward traffic. You can configure the following as destinations for IP Office static routes:

  • LAN1 - Direct the traffic to the IP Office system LAN1.

  • LAN2 - Direct the traffic to the IP Office system LAN2.

  • Service - Direct the traffic to a service in the IP Office configuration. The service settings define the details to connect to a remote data service.

  • Tunnel - Direct the traffic to an IPSec or L2TP tunnel in the IP Office configuration.

  The IP Office system provides two methods of defining a default route for IP traffic that does not match any other specified routes.

  • Default Service - Within the settings for services, one service can be set as the Default Route (Service | Service).

  • Default IP Route - Create an IP Route record with a blank IP Address, blank IP Mask, and set to the required destination for default traffic.

• IPv6 Static Routes

  Linux-based IP Office R12.1 systems can support IPv6. In that case, you can configure static routes for IPv6 traffic using the System > IP Route (IPv6) configuration settings.

• IPv4 Dynamic Routes (RIP)

  IP500 V2 IP Office systems can support RIP (Routing Information Protocol). The IP Office can use RIP to automatically learn routes for data traffic from other routers that also support RIP.

  • By default, static routes entered in the IP Office configuration override any dynamic routes learnt using RIP. This Favor RIP Routes over static routes (System > System) setting control this behavior.

RIP Dynamic Routing

Routers in a network can use Routing Information Protocol (RIP) to automatically advertise details of the routes they know. Through this process, each router can automatically add new network devices to its routing table.

• Each router-to-router link a 'hop'. The routing table can contain routes with up to 15 hops. When more than one route to a destination exists, the IP Office adds the route with the lowest metric (number of hops) to its routing table.

• When an existing route becomes unavailable, after 5 minutes the router marks it as requiring 'infinite' (16) hops. The router advertises this to the network and then removes the route from its routing table.

• The IP Office system also uses 'split horizon' and 'poison reverse' to prevent routes that create loops.

• RIP is a simple method for automatic route sharing and updating within small homogeneous networks. It allows routers to advertise alternate routes when an existing route fails. Within a large network, the exchange of routing information every 30 seconds can create excessive traffic. In addition, the IP Office routing table is limited to 100 static, dynamic, and internal routes.

• When a static route and a dynamic route to the same destination have the same metric, the IP Office uses the static route.

• RIP does not include broadcast (255.255.255.255) and multicast (224.0.0.0) route.