is it possible to use the same IP for two different interfaces on this

[manglai658]

Hi Friends, 

I have built a NG Firewall in HA, is it possible to use the same IP for two different interfaces on this router? so we can plug in these two HA firewall? I know we can easily do this on a layer 3 switch. But my colleague insisted we can do this on the internet Cisco router. 

Thanks

ML

[Karsten Iwen]

There are multiple options to achieve this:

1. Your request could be fulfilled by combining two physical interfaces into a bridge-group. The IP is configured on the Bridge-Group Virtual Interface (BVI). This is a approach that I personally don't like that much, but it could be the right fit for your situation.
2. If you have a modular router you could add a switch module and configure a VLAN for the ports on the switch module. Some Cisco routes use the ethernet-interfaces as switchports directly and you get the same function.
3. You could add an additional WAN-switch between the firewalls and the WNA router. I typically use the 8-port-versions of the Catalyst 1000 or CBS350 for this purpose. But if you only have one ISP and one switch this adds an additional single point of failure.