Vigor 110 + RV042

Discussion in 'Cisco Small Business Routers and VPN Solutions' started by jwab, Apr 26, 2008.

  1. jwab

    jwab Addicted to LI Member

    Hi Guys

    Ok, I got a Draytek Vigor 110 ADSL modem, which I have confirmed working on BT Business Broadband when I make a PPPoE connection through windows xp.

    I connect the Vigor to the WAN 1 port on the RV042, set it to PPPoE, add the username and password, hit save. From there I get nothing I restart the router, the modem, disconnect renew, connect. I just cant get an IP address to pass through.

    The vigor works slightly different to most ADSL modems, it literally handle the PPPoA comms and passes the true IP address to the PC/Router via PPPoE. No bridging.

    So I look at the RV042 system logs and I see Authentication Fail! I don't see why, I'm using the exact same username and password as I do on the windows connection and the previous D-Link ADSL router we had.

    Do anyone know of issues with the Vigor and the RV042? I don't know what else to do. There is nothing really to change on the Vigor, it acts as a protocol handler so it should just pass the username and password to BT and then sign in.

    I've upgraded the RV042 to the latest firmware, and it made no difference.

    Any help much appreciated.
  2. jwab

    jwab Addicted to LI Member

    Ok i've semi cracked it. The problem was the Vigor's DHCP for its web interface. I disabled the DHCP on it and the RV042 now connects fine with PPPoE.

    Now I've got really weird DNS issues. With out touching any DNS settings, ie let them all get assigned automatically by ISP, computers attached to the network can visit fine, also However if I go to I only get 1/2 the site as Inotice some of the contect is from a veriety of domains.

    Furthermore, I can ping let say, but I can't load it on the browser. Sticking in the IP address doesnt help either.

    So I manually put in DNS address on the client computer and in the DNS entry of the RV042, this makes no difference.

    Why would some sites work just fine and others not at all? It's not a cache issue as I can navigate all of the, and do searches on google. But if go to my university eg,, I get a timeout, and also I cant resolve the domain.

    Any pointers?
  3. jwab

    jwab Addicted to LI Member

    I've been advised it might be an MTU issue as PPPoE size is 1498, and as only some websites work and some partial, they may be blocking ICMP messages.

    How can I change the MTU size on the RV042?
  4. jwab

    jwab Addicted to LI Member

    Ok found where it is, will change it tonight to see if it works
  5. Toxic

    Toxic Administrator Staff Member

    for ADSL you need to use an MTU of 1492 or less. the size change has to be in 8 byte sizes.

    Cable: 1500 or lower
    ADSL: 1492 or lower.

    it sounds like you are getting packet loss due to the incorrect MTU size.

    if your running windows, try using tcpoptimizer from and test the maximum MTU size you can use.
  6. jwab

    jwab Addicted to LI Member

    Yes it was MTU

    So for them you have a Linksys RV042 + Vigor 110

    Plug it all in, remove the DHCP service from the Vigor
    Set a WAN slot on the RV042 to PPPoE
    Enter username and password, with NO service name.
    Set the MTU to 1430 for an 8MB line... you can go figure for other size lines.

    Hit connect, and all should be rosy.

    Now I got an issue with my RV042 at home. After finding about tweaking MTU's I decided to do my own.

    Using cable modem, I can have an MU of 1500. So I set this manually in the firewall page but when I check the logs I get

    I restart the RV042, I disconnect and connect, but still the MTU is set to 576, what gives?
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