1721 PPoA with Zyxel in Bridge Mode

[ATCal]

Setting up an ADSL connection for our UK office. I have a 1721 router with 2 ethernet WICs. The Zyxel modem is set to bridge mode.
I need to know how to configure the 1721 WAN ethernet interface and the authentication required.

Thanks-

Al

 

[burtsbees]

http://www.tek-tips.com/viewthread.cfm?qid=1429836&page=8

Burt

 

[burtsbees]

For a GUI based tool called SDM (free with free cisco.com registration)...

http://www.cisco.com/en/US/prod/collateral/routers/ps5318/product_data_sheet0900aecd800fd118.html

Burt

 

[ATCal]

Ok, but I don't have a ADSL WIC, I have 2 Ehternet WICs. My understanding is that the modem will perform the ADSL conversion, but that my router needs to perform the authentication.

Thanks-

Al

 

[burtsbees]

Crap, I thought the first link was what you needed...

Why not let the modem do the authentication, and the router just NAT? Also, have you looked at SDM? I know your set up would involve vpdn group configuration, but I have never done it myself. Just with the WIC...

Burt

 

[ATCal]

My understanding is that with the modem in bridge mode, it is just a passive device, not doing anything including authentication.
This whole problem arose because I needed a block of IPs that need to work through a PIX. The sent me this Zyxel modem/NAT router which only has one addressable interface. So we put it in bridging mode, but the PIX does PPoE, not PPoA, so I bought the 1721 router that is supposed to do PPoA. Now I know that they DO have the ADSL WIC for the 1721, but Cisco's docs on the 1721 show it able to be configured either AS the DSL modem (with ADSL WIC) ir behind the modem (Ethernet WIC).
I can't help but think I am somehow overcomplicating this.

Thanks,

-Al

Al

 

[burtsbees]

Behind the modem, the 1721 should just do NAT. The modem in bridge mode should negotiate the PPPoA session. There is a way to configure the 1721 to have a vpdn group and thus create a dialer interface, but I have not heard anyone that really does this...

from global config mode...

vpdn enable
vpdn-group 1
request-dialin
protocol pppoa

interface Ethernet0
description ADSL WAN Interface
no ip address
no ip redirects
no ip unreachables
no ip proxy-arp
no ip mroute-cache
half-duplex
pppoa enable
pppoa-client dial-pool-number 1
no cdp enable

interface Ethernet1
description LAN Interface
ip address 192.168.1.1 255.255.255.0
no ip redirects
no ip unreachables
no ip proxy-arp
ip nat inside
no ip mroute-cache
speed auto
no cdp enable

interface Dialer1
description ADSL WAN Dialer
ip address negotiated
no ip unreachables
ip mtu 1492
ip nat outside
encapsulation ppp
no ip mroute-cache
dialer pool 1
dialer-group 1
no cdp enable
ppp authentication chap callin
ppp chap hostname xxxxxxxxxxxx
ppp chap password xxxxxxxxxxxxx
ppp pap sent-username xxxxxxxxxxx password xxxxxxxxxxxx

ip nat inside source list 10 interface Dialer1 overload
ip route 0.0.0.0 0.0.0.0 Dialer1
access-list 10 permit 192.168.1.0 0.0.0.255
dialer-list 1 protocol ip permit
Something like that...

I'm not sure how to configure the pppoa encapsulation, or rather where...that's why I suggest to use the modem for the negotiation and the router for NAT, or just buy a WIC-1ADSL. If not anything else, try SDM.

Burt

 

[ATCal]

So dumb question-

I am following your sample above, but I don't have ppoa as an available auth method for the vpdn.
Do I need a particular software set for this?

Thanks-

Al