BT HomeHub subnet issue

[Jamieuwic]

Hi,

I would like to use a different subnet internally than the subnet used by my BT broadband router.

I have a Cisco switch with 2 vlans, Vlan 10 and Vlan 20. Vlan 10 is internal vlan 20 is external. Vlan 20's ip address is 172.16.50.2 Vlan 10's address is 192.168.10.2.

The BT router has a leg in vlan 20 and it's IP is 172.16.50.3. Any PC in vlan 20 can access the internet fine. If a PC is in vlan 10 it can't access the internet.

I have route 0 on the switch which sends 0.0.0.0 0.0.0.0 vlan 20.

I'm pretty sure the issue is with my BT home hub. If someone could find the time to help I would really appreciate it.

J.

 

[coxhaus]

I assume your switch is running in layer 3 mode because you have a default route and not a default gateway. I would change default route to point to the IP address of the BT broadband router which I think is 172.16.50.3. I assume the Cisco switch is doing the VLAN routing so the port connecting the router should be an access port not a trunk port. This info is not stated. You need to have a route statement on the router for VLAN10 pointing to the switch.

 

[Jamieuwic]

Thanks for the reply coxhaus.

Everything you have assumed is correct. I have tried pointing the default route to the bt router but it didn't work.

J.

 

[coxhaus]

Thanks for the reply coxhaus.

Everything you have assumed is correct. I have tried pointing the default route to the bt router but it didn't work.

J.

Pointing the default route is only half of equation as you still need to have a routing statement on the router for VLAN10 pointing to the layer 3 switch. If you don't have both it will not work.