ip default-route vs ip route

Ran into a small problem yesterday, where a sub-contractor dispatched a technician to provision a new DSL line (on a Cisco 851) for me at one of our retail stores. It really was not a huge change. Mostly, just changing the ip address and default route.

After 3 hours, the technician calls me back saying it’s not working, and if I gave him the right information. Not arguing, seeing as how I can screw-up a mechanical pencil, I check my information, and all seems right.

I webex into his laptop, and requested him to console to the router. After doing a ‘show run’, I see the problem. He used “ip default-route” instead of “ip route”. And, apparently, he’s not alone. This seems to stump alot of technicians new to Cisco.

The fast

• ip default-gateway - Used on Layer2 managed switches (i.e. no routing)
• ip route 0.0.0.0 0.0.0.0 - Used to add a default route, routing entry to a route table

The explanation:

So, if you have a managed switch, that means you must have an IP Address on it to manage it. But, what if you are accessing the switch from another network? The interface with the IP Address needs to know where to go. You can’t use “ip route”, because there isn’t a routing table to change…. it’s a Layer2 switch. This is why Cisco chose to use a different command.

Now, I agree with Chris Jones (@IPv6Freely) that Cisco should change that command to something a bit more intuitive. I’m not sure about “ip management-route”, but maybe. It makes sense.

AK2TND3TKVC3