Static Route Example

See the Static Route Network Diagram for the addresses used in this example.

The goal is to create a static route that allows return traffic to the host at 20.30.1.2 in destination network 20.30.1.0/24.

The packet can take any path to reach the destination. When a network receives a packet on an interface, it determines where to forward the packet for the best route to a destination.

Note	The DMZ does not have a static route as it is connected directly to the interface.

For example, consider the following two routes for reaching the destination.

Route 1:

Procedure

Step 1	Packets come back to the outside interface, 209.165.201.0/27, looking for 20.30.1.2.
Step 2	We direct the packets to use the inside interface to get to the gateway 192.168.1.2, which is on the same network as the destination.
Step 3	From there, we identify the destination network by the gateway address for that network, 20.30.1.1.
Step 4	The IP address 20.30.1.2 is on the same subnet as 20.30.1.1. The router forwards the packet to the switch, the switch forwards the packet to 20.30.1.2. Interface:Inside Destination_N/W:20.30.1.0/24 Gateway: 192.168.1.2 Metric: 1

Route 2:

Procedure

Step 1	Packets come back to the outside interface, 209.165.201.0/27, looking for 20.30.1.2.
Step 2	We direct the packets to use the internal interface to get to the gateway 192.168.50.20, which is multiple hops away from the destination network.
Step 3	From there, we identify the destination network by the gateway address for that network, 20.30.1.1.
Step 4	The IP address 20.30.1.2 is on the same subnet as 20.30.1.0. The router forwards the packet to the switch, the switch forwards the packet to 20.30.1.2. Interface:Inside Destination_N/W:20.30.1.0/24 Gateway: 192.168.50.20 Metric: 100 Here is what the completed Add Static Route table would like for these routes.