Connection Error 721 - PPP

This is a discussion on Connection Error 721 - PPP ; Here is the setup. I have a XP machine trying to connect to a embedded device. The connection uses PPP and CHAP. Configuration on the XP machine Hardware flow control disabled Modem Error control disabled Modem Compression disabled Under Security ...

+ Reply to Thread
Results 1 to 2 of 2

Thread: Connection Error 721

  1. Connection Error 721

    Here is the setup.

    I have a XP machine trying to connect to a embedded device. The
    connection uses PPP and CHAP.

    Configuration on the XP machine
    Hardware flow control disabled
    Modem Error control disabled
    Modem Compression disabled

    Under Security
    I have Advanced chosen using CHAP only.

    Networking Settings for PPP
    LCP extensions is disabled
    Software compression disabled
    Negotiate multi-link is disabled

    I also have the IP setup for the correct address.

    What happens is the modems negotiate and connect.

    The remote device sends a LCP request and XP never responds.
    XP sends a request and remote device acknoledges.

    This process is repeated 10 times.

    I know the remote device is working because I can use the same setup
    on 5 other XP machines and it connects fine. Only 1 machine is
    failing.

    I don't know what is happening to the request from the remote device,
    but XP seems to be throwing it away. It does not send a LCP reject.

    I have tried all sorts of variations of the settings but to no luck.

    Some info I have found on the web, but I don't know if this is the
    cause. I found something saying that the PPTP is blocking the GRE and
    that is why the packet is discarded.

    Please HELP!!

  2. Re: Connection Error 721

    In article <8a2cbfa9.0407220558.44b8767e@posting.google.com>,
    kensmtih1976 wrote:

    >I have a XP machine trying to connect to a embedded device. The
    >connection uses PPP and CHAP.


    While this newsgroup is about ppp, most of us don't use windoze, so
    you're going to have a hard time getting an answer. I saw this
    article Thursday, and was hoping someone else could respond. The
    microsoft implementation of CHAP may be different, and they may
    require certain options if you are using Encrypted passwords, or
    one of the microsoft "improvements" that intentionally break things.

    >The remote device sends a LCP request and XP never responds.
    >XP sends a request and remote device acknoledges.


    Likely, you have a parameter wrong , but I'm afraid we can't tell
    what from a verbal description. The "721" error does mean
    something to a microsoft expert - did you try a google search?

    >I know the remote device is working because I can use the same setup
    >on 5 other XP machines and it connects fine. Only 1 machine is
    >failing.


    About the best way to troubleshoot this is to go to the box everyone
    can connect to, and make connection attempts from one that works, and
    the one that doesn't. The key here is to use the logging facility
    that microsoft included in place of a proper debug mode. Again, I
    don't use windoze, so I'm not even sure this "clue" is correct - it's
    what I've seen from past postings:

    -----------------
    >Try turning on PPP logging. I'm not sure offhand how to do this in XP;
    >you might try the Win2k method:
    >http://support.microsoft.com/default.aspx?scid=kb;[LN];234014


    Yes, that's it, it also works in WinXP Pro.
    -------------------

    Please do NOT post the log files. The Unix logs are bad enough (as
    much as 30 lines long), but microsoft intentially tries to intimidate
    anyone attempting to see such technical things as a ppp connection.
    They do this by including tons of techno-babble, and comments, and
    interpretations of what is a relatively simple action. What you want
    to do is to compare the "working" and "non-working" connection logs.
    What you really need to know is going to show up in four to eight lines
    of log text, likely the first set of LCP packets from each peer. Post
    not more than a dozen lines if you need an explanation, but again, the
    people here are ppp experts, not microsoft.

    Hope this helps,

    Old guy

+ Reply to Thread