DD-WRT and PPPOA BT ADSL using a ST510 v6

This is something I did a while ago, but I thought I should write it up properly.

The problem:

DD-WRT does not support PPPoA ADSL.

For my old PPPOE ADSL internet connection I had a WRT610n v2 running DD-WRT and a separate simple ADSL2+ modem (ST510 v6) which I have running in bridged mode to avoid double NAT. This worked great as DD-WRT supports PPPOE, however I moved house and had to set up a new connection with British Telecom who use PPPOA.

Phoning BT tech support was as pointless as I thought it would be. DD-WRT does not appear on their scripted responses and they all think that the BT Home Hub is the best thing since boobs despite the fact that it is quite clearly crap – a single gigabit ethernet port! Really? WTF?

The solution:

Basically I had to set up the st510 v6 modem into half bridging mode. From what I understand of it, this involves getting the modem to handle the PPPoA connection, then enabling PPTP on it for the DD-WRT router to be able to connect to it and supply the credentials.

To configure the modem:

  1. Use the standard wizard in the web interface and choose any configuration you like (I picked a PPPoA template) but make sure that you choose a VPI/VCI that is NOT 0.38. Complete the wizard and let the thing settle.
  2. Use the web interface to configure the modem how you like. Things you probably want to do include:
    1. Disabling the firewall (the DD-WRT router has a better one)
    2. Setting the password to something decent
    3. Turning off DHCP (again we’ll let DD-WRT handle that)
    4. Simplifying the network interfaces. My modem defaults to have an IP of 10.0.0.138 which is fine, but it also creates a vlan in the 192.168.1.x range. I removed this. N.B this is why you have to assign your local IP statically for this part.
  3. Restart the modem just to help it settle.
  4. Telnet into the modem (Google it if you’re not sure what telnet is)
  5. Issue the following commands:
    (You can ignore any messages about things being in use and unable to be deleted)

    ppp relay flush
    eth flush
    atm flush
    ppp flush
    atm phonebook flush
    saveall
    atm phonebook add name=BrPPPoA_ph addr=0.38
    service system modify name=PPTP state=enabled
    saveall
    exit
  6. Use the modem’s web interface to restart the modem.
  7. Hook the modem up to the wan port of the DD-WRT modem and log into DD-WRT.
  8. In the wan settings of DD-WRT use settings like mine:DD-WRT PPTP Settings
    (Don’t worry about the subnet mask and gateway, they will set itself when your connection is established).

That’s it! Good luck 🙂

Originally posted on the BT forums here: http://community.bt.com/t5/BB-Speed-Connection-Issues/Alternative-Modem-Router-using-DD-WRT/td-p/295165

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16 Comments on “DD-WRT and PPPOA BT ADSL using a ST510 v6

  1. Hi there, I too am experiencing the pain of changing to an ISP that uses PPPoA.

    At the moment I cannot get my D-link 320b modem to connect to my Asus RT-N66U (running dd-wrt) so its lying on the sofa beside me. 😦

    To resolve my problem I was going to buy the modem you’ve used here and follow this guide, my only question is that I have my network setup on the 192.168.1.x IP range. would you be kind enough to point out any changes I need to make to adapt your guide? at the moment from your dd-wrt setup I am unsure what I would need to set the WAN IP address as, my actual WAN IP from the ISP is not static.

    Thanks for the time it takes to make this guide, and others!

    Phil

    • Hi Phil,
      Really sorry for the slow reply – I only just noticed your comment :-S

      You shouldn’t need to change anything, I use the same range for my network. As for the WAN address, you need to set it to something in the same subnet as the IP your modem gives itself. In my case, the modem uses 10.0.0.138 so I set my WAN IP to 10.0.0.1, but anything in the 10.0.0.x range would be fine.

      You can leave the gateway blank, but set the Gateway (PPTP Server) to the IP of your modem.

      Hope this isn’t too late to help,
      Charlie

  2. I came across this but I’m rolling with a much simpler solution:

    I have a D-Link DSL-320B acting as the modem
    A WRT54GL as the LAN router running DD-WRT

    The D-Link is configured with ADSL (PPPoA) as standard, nothing special going on here.
    The WRT is configured with a Static WAN to the LAN IP of the D-Link
    The WRT LAN is configured as DHCP.

    D-Link WAN: PPPoA (ISP Dynamic IP)
    D-Link LAN: 192.168.1.0/23 (192.168.1.1)
    WRT WAN: 192.168.1.0/23 (192.168.1.2)
    WRT LAN: 192.168.2.0/23 (192.168.2.1)

    The /23 subnet means I can still talk to the D-Link through the WRT with ease.

  3. Hi Charles

    I’m trying to follow your guide, but I’m a little confused on step D. *but it also creates a vlan in the 192.168.1.x range. I removed this. N.B this is why you have to assign your local IP statically for this part.*
    Once I delete the 192.168.1.x range in the router I lose access to the router and need to reset it. Can you expand on the NB. comment please?

    Thanks

    • Hi Paddy,
      Basically, when you delete the vlan, the modem can’t allocate you an IP any more, so you need to do this yourself. If you don’t know how to do this, don’t worry – just Google ‘how to assign a static IP’ its pretty straight forward.

      Let me know how you get on 🙂

      Charlie

      • Hi Charlie
        That worked, I just set my laptop static ipaddress to 192.168.1.50.
        I’ve the ST510 setup following your guide. Internet in use at the minute so hopefully get a chance tomorrow to test from point 7 onwards. Will let you know. Thanks

  4. Hi Charlie,

    Just wondering what VPI/VCI settings worked for you?
    The only ones I can get to work are 0.38, but your instructions explicitly state that I shouldn’t use these. I’m using a TP-LINK TD-8817 with NETGEAR R7000-100UKS.

    Thanks

    Rich

    • Honestly I can’t remember why I said you can’t use 0.38… I probably read it in a forum somewhere.

      If it works for you then that’s the main thing.

      Sorry I can’t be more helpful 🙂

    • On second thoughts – it may be because in step 5 I use a command to set 0.38 and didn’t want it to conflict.

      Also, my instructions were written for BT, you may need to use different values if you are using a different provider.

  5. Hi Charles,

    Will this avoid the double NAT issue? What’s the difference between this and full bridge (modem only mode)?

    Thanks
    Matt

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