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New Member

Cisco 878 Bridging


Basically what am I trying to do is establishing a PPPOE connection from our FW to Cisco 878, and get the public IP to the untrust interface of the FW. The interface of the FW of PPPoE(SSG520 - Netscreen) is quite simple..

But on the 878 bridging, I think I am failed :\

I know that these commands are used for briding...

no ip routing


Interface ethernet 0

bridge-group 1


Interface serial 0

bridge-group 1


bridge 1 protocol ieee

My questions are:

1) Which interfaces should I put in the "bridge-group 1" (My Fast ethernets are just switches, they are used in a VLAN) Dialer 0, VLAN 1, ATM 0, Virtual Teplates...etc??

2) Should I use the

"ppp pap sent-username MYUSERNAME password 0 MYPASSWORD" on the C878 to establish the connection or ommit it (to use in the FW) (without this command Virtual access is going up and down)

3) should I give my VLAN interface an IP?

4) Any other config missings??

Please check the config attached.

I would be deeply glad for any help.(or configs)

Best Regards,


New Member

Re: Cisco 878 Bridging

any ideas?


Re: Cisco 878 Bridging


1- You are missing the command "bridge-group 1 route ip".

2- You will need to issue the command ppp pap sent-username x password x in case the ISP will authenticate your router. In normal cases, all ISPs authenticate the clients so you have to issue this command. One thing to check wheather your ISP is using PAP or CHAP as well. Chap commands are different:

PPP chap hostname x

PPP chap password x

4- You need to set an IP address on the FW same as the dialer interface and you should put the dialer androuter ethernet which is connected to the firewall in the bridge group.

I am trying to help as much as I can eventhough my knowledge is limited in bridging,

Let me know how it goes,

Appreicate your rating,


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