Question

A network engineer is troubleshooting a small LAN network with one border router, GW01 that connects to the Internet Service Provider’s (ISP) network. GW01 uses its Serial 0/2/1 interface to connect to the ISP’s router. Everyone on the LAN network lost connectivity to the Internet. Upon troubleshooting the issue, the network engineer notices the following message after typing show ip route. Gateway of last resort required but not set. What do you suggest the network engineer do to rectify this issue? Assume the problem is only on the organization’s LAN side of the network. Provide as much information as possible including specific commands and all required parameters.

Answer 1

Create a default route on the border router. Check the NAT configuration and network addresses.

Step-by-step explanation:

The LAN or local area network is a network meant for a small geographic area, ranging from a small home office to office building.

For a LAN to be connected to the internet, it is subscribed to a ISP. The ISP provides the internet/ global WAN resources to the LAN. The border router or stub is configured with a gateway of last resort or default route to route packets to the WAN network and a Network address translation, NAT, is used for a large LAN.

The syntax for default route configuration on the border router is;

Router(config)# IP route 0.0.0.0 0.0.0.0 s0/0/1