Connect from firewall to Cisco 877 in Bridged mode

Question

I have a Cisco 877 in bridged mode acting as an ADSL2 modem only. My firewall is doing PPPOE and the internet works great.

What I would like to do is give vlan1 on the Cisco 877 an IP address e.g. 10.10.10.1/24 and then give my firewall a secondary WAN IP of 10.10.10.2 so that I can connect to the Cisco 877 and manage it without having to use the console port (kick off a reboot from the LAN side).

My working bridge config is

!
interface ATM0
no ip address
no atm ilmi-keepalive
pvc 8/35
encapsulation aal5snap
!
dsl operating-mode auto
bridge-group 1
!
!
interface Vlan1
no ip address
bridge-group 1
!
bridge 1 protocol ieee
!

in order to do what I want, I would have thought I could simply add an IP to vlan1 e.g.

!
interface ATM0
no ip address
no atm ilmi-keepalive
pvc 8/35
encapsulation aal5snap
!
dsl operating-mode auto
bridge-group 1
!
!
interface Vlan1
ip address 10.10.10.1 255.255.255.0
bridge-group 1
!
bridge 1 protocol ieee
!

however, this simply does not work. I see nothing in the ARP table on the firewall WAN interface that has a secondary IP of 10.10.10.2

I followed Cisco 877 as PPPoA/PPPoE bridge (no routing) - how to make it listen to IP for management? which suggests to use

bridge irb

and then

bridge 1 protocol ieee
bridge 1 bridge ip

Anyone able to help, thanks!

score 0 · Accepted Answer · answered Feb 13 '13 at 14:45

You need to create a BVI interface and then give that BVI interface an ip address, e.g.:

config term
int BVI1
ip address 10.10.10.1 255.255.255.0

By virtue of putting both adapters in bridge group 1, you've bridged them together. By creating a BVI1 interface, you allow your router to have an ip address on that same bridge (The number after BVI coincides with the bridge group you've defined)

Connect from firewall to Cisco 877 in Bridged mode

1 Answers1