Cant ping outside of network

[Paul Smith]

I have set up a Cisco 871 router but I am only using it as a switch. I have int fa1 as an access port for vlan 801 and int fa2 for vlan 802. I have int fa3 set up as trunk to my Cisco 2821 router. Fa4, the WAN port is not connected.

I have one host connected to the 871 fa2 port. It has received the correct DHCP parameters and can connect out to the internet fine.

On the 871 I have set up an SVI for vlan 802, which is 10.10.2.62. From the 871 I cant's ping out to the internet or another network. Can you see why?

The config for the 871 is here -

http://pastebin.com/hkvY3ygv

The config for the 2821 is here -

http://pastebin.com/WDzrQPJd

[Philip D'Ath · Accepted solution]

Add a default route on the 871.

ip route 0.0.0.0 0.0.0.0 10.10.2.3

[Paul Smith]

It worked. Very slick my friend. That must be new record :)

So having the correct default gateway was not enough? I have set up SVI's on switches before and all I needed was the correct default gateway. As you know you can't set static routes on layer 2 switches yet they can communicate across networks?

[Philip D'Ath]

The "default-gateway" command is used when routing is disabled (as on a layer 2 switch) and "ip route" is used for, well, when routing is enabled.

Routing is enabled by default on Cisco routers (no surprises there).  If you disabled routing ("no ip routing") then you could go back to using "default-gateway".

[Paul Smith]

Thanks Philip. I guess the other thing I am trying to get my head around is why the network host worked fine from within vlan 802 but the router SVI (same vlan) did not. I understand what you said about routing being enabled but this is interesting.

[Philip D'Ath]

The network host is switched at layer 2. It does not use any layer 3 routing functionality of the router.