Unable to connect an ASA 5505 with PPPoE via 837 router in Bridge mode

Unanswered Question
Dec 18th, 2007

We have a Cisco ASA 5505 that we want to get connected to our ISP. We use

a Cisco 837 series router in bridge mode to pass the PPPoE traffic from the ISP to the ASA

and viceversa.

The thing is we are unable to have the PADI answered. We have even tried to use a Windows

PPPoE client connected to the router.

We have connected a sniffer in the 837 and we have seen the PPPoE traffic comming but

never answered.

I have this problem too.
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mannschaft Tue, 12/25/2007 - 08:02


is your ASA get IP adresse from the bridged router ?

what would you like to do with this configuration ?


nachete1979 Wed, 12/26/2007 - 02:41


I would like to get an IP via PPPoE from my ISP to the ASA directly in order to improve the security in the network and enhance the VPN capabilities.


mannschaft Wed, 12/26/2007 - 07:16

Hi nachete

ok fine, that's a good idea.let's start with Cisco837 configuration. according to your Cisco 837 configuration lines, i didn't see any thing about BVI1 interface.so i suggest you to add these lines :

interface BVI1

ip address your.ip.address your.mask

ip nat outside

ip virtual-reassembly

ip tcp adjust-mss 1400

load-interval 30

after doing this your ASA must got IP adress from your ISP. if not try to post all your Cisco Configuration lines to correct.


nachete1979 Wed, 12/26/2007 - 07:46


Thanks for the reply. I have tried that config but, as long as my ISP does not give me an ip address I can not configure that BVI interface.


mannschaft Wed, 12/26/2007 - 08:30

you mean that you have a dynamic IP ?

can you post your cisco837 config to see ?!



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