Can't get PPP 2.4.3 to do anything under Linux - PPP

This is a discussion on Can't get PPP 2.4.3 to do anything under Linux - PPP ; I'm trying to get PPP 2.4.3 to link two Linux 2.6 systems via RS-232 without success. I've read this group's FAQ, read http://www.linux.com/howtos/PPP-HOWTO/index.shtml , and Googled for other hints but nothing seems to help. With my new system, I try ...

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Thread: Can't get PPP 2.4.3 to do anything under Linux

  1. Can't get PPP 2.4.3 to do anything under Linux

    I'm trying to get PPP 2.4.3 to link two Linux 2.6 systems via RS-232
    without success. I've read this group's FAQ, read
    http://www.linux.com/howtos/PPP-HOWTO/index.shtml, and Googled for
    other hints but nothing seems to help.

    With my new system, I try to follow the directions in section 29 of the
    PPP-HowTo neither the preliminary test with no routing nor the more
    complete client/server situation works. In both cases, pppd runs,
    produces no errors, but there is no ppp0 interface on either system. I
    configured and ran syslogd and ran ppp with debug and the log contains
    nothing that seems unusual:

    Jan 1 00:01:35 Test3 daemon.notice pppd[152]: pppd 2.4.3 started by
    root, uid 0
    Jan 1 00:01:36 Test3 daemon.notice pppd[152]: Removed stale lock on
    ttyAM0 (pid 221)

    I have an older system (PPP 2.4.2b3, Linux 2.4) which works but I had
    nothing to do with its development and the developer isn't available
    for consultation. Using two of the older systems, I can configure a
    server and a client, connect them via serial, and ping between them.
    I'd hoped to learn something from that. I only learned that the
    previous developer got it to work. ;-)

    I tarred up the configuration of my old client, restored it on one of
    my new systems, adjusted for the difference in serial port device
    names, and tried connecting it to my old server. Same results on the
    new client: pppd runs but there is no ppp0 interface or helpful message
    in the log.

    I've got 20 years experience with lots of network systems but no
    background with PPP. If someone could point me at a resource that can
    explain the lack of activity and information, I would surely appreciate
    it. Thanks.

    Chris


  2. Re: Can't get PPP 2.4.3 to do anything under Linux

    cnelson@nycap.rr.com writes:
    > With my new system, I try to follow the directions in section 29 of the
    > PPP-HowTo neither the preliminary test with no routing nor the more
    > complete client/server situation works. In both cases, pppd runs,
    > produces no errors, but there is no ppp0 interface on either system. I
    > configured and ran syslogd and ran ppp with debug and the log contains
    > nothing that seems unusual:
    >
    > Jan 1 00:01:35 Test3 daemon.notice pppd[152]: pppd 2.4.3 started by
    > root, uid 0
    > Jan 1 00:01:36 Test3 daemon.notice pppd[152]: Removed stale lock on
    > ttyAM0 (pid 221)


    If you're really running with the "debug" option and if your
    syslog.conf file is configured properly, then that's a HIGHLY
    suspicious and unusual result.

    You should at least have an indication that pppd is opening the port
    and attempting to dial or send LCP messages. If there's not even
    that, then I'd suspect that the serial port itself is broken.

    But, first, please post your complete pppd configuration. There's
    little that can be done if complete information isn't provided.

    > I've got 20 years experience with lots of network systems but no
    > background with PPP. If someone could point me at a resource that can
    > explain the lack of activity and information, I would surely appreciate
    > it. Thanks.


    You might try doing 'strace' or whatever the Linux tool is that traces
    system calls and see what pppd is doing when it gets stuck.

    --
    James Carlson, KISS Network
    Sun Microsystems / 1 Network Drive 71.232W Vox +1 781 442 2084
    MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677

  3. Re: Can't get PPP 2.4.3 to do anything under Linux

    James Carlson wrote:
    > cnelson@nycap.rr.com writes:
    > > ... I configured and ran syslogd and ran ppp with debug and the log
    > > contains nothing that seems unusual:
    > >
    > > Jan 1 00:01:35 Test3 daemon.notice pppd[152]: pppd 2.4.3 started by
    > > root, uid 0
    > > Jan 1 00:01:36 Test3 daemon.notice pppd[152]: Removed stale lock on
    > > ttyAM0 (pid 221)

    >
    > If you're really running with the "debug" option and if your
    > syslog.conf file is configured properly, then that's a HIGHLY
    > suspicious and unusual result.


    My command line for invoking pppd is:

    pppd debug file /etc/ppp/options.cli1

    > You should at least have an indication that pppd is opening the port
    > and attempting to dial or send LCP messages. If there's not even
    > that, then I'd suspect that the serial port itself is broken.


    There's no dialing becaue it's a direct serial connection through a
    null-modem connection. Yes, it's possible my serial port is hosed
    (though getty on it give me a login prompt and I can log in and work
    without any problem).

    > But, first, please post your complete pppd configuration. There's
    > little that can be done if complete information isn't provided.


    /etc/ppp/options.cli1 (referenced in the command line above) is:

    noipdefault
    persist
    /dev/ttyAM0
    38400
    name PPPLink

    What else would you want to see?

    > > I've got 20 years experience with lots of network systems but no
    > > background with PPP. If someone could point me at a resource that can
    > > explain the lack of activity and information, I would surely appreciate
    > > it. Thanks.

    >
    > You might try doing 'strace' or whatever the Linux tool is that traces
    > system calls and see what pppd is doing when it gets stuck.


    I tried strace and didn't see much (or saw too much and nothing seemed
    to be helpful). I'll try again. Thanks.


  4. Re: Can't get PPP 2.4.3 to do anything under Linux

    cnelson@nycap.rr.com writes:
    > There's no dialing becaue it's a direct serial connection through a
    > null-modem connection. Yes, it's possible my serial port is hosed
    > (though getty on it give me a login prompt and I can log in and work
    > without any problem).


    That's helpful to know.

    Do the control lines work as well? Do you need to specify "local" to
    avoid pppd's use of DCD?

    > /etc/ppp/options.cli1 (referenced in the command line above) is:
    >
    > noipdefault
    > persist
    > /dev/ttyAM0
    > 38400
    > name PPPLink


    That seems mostly ok.

    > What else would you want to see?


    What's in /etc/ppp/options? There's no way to stop pppd from reading
    that file -- it *always* reads it if it's present.

    Do you have daemon.debug directed to a file in /etc/syslog.conf? And,
    if you had to change that file, did you touch that file into existence
    and SIGHUP syslogd?

    > I tried strace and didn't see much (or saw too much and nothing seemed
    > to be helpful). I'll try again. Thanks.


    Posting some actual output rather than a summary would be helpful.

    --
    James Carlson, KISS Network
    Sun Microsystems / 1 Network Drive 71.232W Vox +1 781 442 2084
    MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677

  5. Re: Can't get PPP 2.4.3 to do anything under Linux

    James Carlson wrote:
    > cnelson@nycap.rr.com writes:
    > > There's no dialing becaue it's a direct serial connection through a
    > > null-modem connection. Yes, it's possible my serial port is hosed
    > > (though getty on it give me a login prompt and I can log in and work
    > > without any problem).

    >
    > That's helpful to know.
    >
    > Do the control lines work as well?


    I'm not positive and I don't have my breakout box handy.

    > Do you need to specify "local" to avoid pppd's use of DCD?


    I can try that. Thanks for the suggestion.

    > > /etc/ppp/options.cli1 (referenced in the command line above) is:
    > >
    > > noipdefault
    > > persist
    > > /dev/ttyAM0
    > > 38400
    > > name PPPLink

    >
    > That seems mostly ok.
    >
    > > What else would you want to see?

    >
    > What's in /etc/ppp/options? There's no way to stop pppd from reading
    > that file -- it *always* reads it if it's present.


    lock
    crtscts
    asyncmap 0
    modem

    Bingo! "modem" seems wrong. Shouldn't that be "local". (Though this
    same configuration works on my older system with PPP 2.4.2.)

    > Do you have daemon.debug directed to a file in /etc/syslog.conf?


    # more /etc/syslog.conf
    daemon.* /var/log/pppd

    > And,
    > if you had to change that file, did you touch that file into existence
    > and SIGHUP syslogd?


    I had to start syslogd, it doesn't run by default on our embedded
    system.

    > > I tried strace and didn't see much (or saw too much and nothing seemed
    > > to be helpful). I'll try again. Thanks.

    >
    > Posting some actual output rather than a summary would be helpful.


    No doubt. Though I'd have to limit strace's output to something
    sensibly short.


  6. Re: Can't get PPP 2.4.3 to do anything under Linux

    Chris Nelson wrote:
    > ...
    > > Do you need to specify "local" to avoid pppd's use of DCD?

    >
    > I can try that. Thanks for the suggestion.
    > ...
    > > > What else would you want to see?

    > >
    > > What's in /etc/ppp/options? There's no way to stop pppd from reading
    > > that file -- it *always* reads it if it's present.

    >
    > lock
    > crtscts
    > asyncmap 0
    > modem
    >
    > Bingo! "modem" seems wrong. Shouldn't that be "local". (Though this
    > same configuration works on my older system with PPP 2.4.2.)


    Changing "modem" to "local" in /etc/ppp/options gives:

    Jan 1 01:21:05 Test3 syslog.info -- MARK --
    Jan 1 01:26:33 Test3 daemon.notice pppd[238]: pppd 2.4.3 started by
    root, uid 0Jan 1 01:26:33 Test3 daemon.notice pppd[238]: Removed stale
    lock on ttyAM0 (pid 225)
    Jan 1 01:26:33 Test3 daemon.debug pppd[238]: using channel 1
    Jan 1 01:26:33 Test3 daemon.info pppd[238]: Using interface ppp0
    Jan 1 01:26:33 Test3 daemon.info pppd[238]: Connect: ppp0 ->
    /dev/ttyAM0
    Jan 1 01:26:33 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    Jan 1 01:26:36 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    Jan 1 01:26:39 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    Jan 1 01:26:42 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    syncmap 0x0> agic 0x3fea5345> comp> ccomp>]

    (though still no ppp0 interface).


  7. Re: Can't get PPP 2.4.3 to do anything under Linux

    Chris Nelson wrote:
    > ...
    > Changing "modem" to "local" in /etc/ppp/options gives:
    >
    > Jan 1 01:21:05 Test3 syslog.info -- MARK --
    > Jan 1 01:26:33 Test3 daemon.notice pppd[238]: pppd 2.4.3 started by
    > root, uid 0Jan 1 01:26:33 Test3 daemon.notice pppd[238]: Removed stale
    > lock on ttyAM0 (pid 225)
    > Jan 1 01:26:33 Test3 daemon.debug pppd[238]: using channel 1
    > Jan 1 01:26:33 Test3 daemon.info pppd[238]: Using interface ppp0
    > Jan 1 01:26:33 Test3 daemon.info pppd[238]: Connect: ppp0 ->
    > /dev/ttyAM0
    > Jan 1 01:26:33 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    > Jan 1 01:26:36 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    > Jan 1 01:26:39 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    > Jan 1 01:26:42 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    >
    > (though still no ppp0 interface).


    After a while, the log contains:

    Jan 1 00:17:28 Test3 daemon.warn pppd[177]: LCP: timeout sending
    Config-Requests
    Jan 1 00:17:28 Test3 daemon.notice pppd[177]: Connection terminated.
    Jan 1 00:17:28 Test3 daemon.debug pppd[177]: using channel 8
    Jan 1 00:17:28 Test3 daemon.info pppd[177]: Using interface ppp0
    Jan 1 00:17:28 Test3 daemon.info pppd[177]: Connect: ppp0 ->
    /dev/ttyAM0
    Jan 1 00:17:28 Test3 daemon.info pppd[177]: sent [LCP ConfReq id=0x2
    syncmap 0x0> agic 0x5f371907> comp> ccomp>]
    Jan 1 00:17:28 Test3 daemon.warn pppd[177]: tcflush failed: Bad file
    descriptor
    Jan 1 00:17:28 Test3 daemon.warn pppd[177]: tcsetattr: Invalid
    argument (line 1001)
    Jan 1 00:17:28 Test3 daemon.info pppd[177]: Exit.

    So it seems to be trying to create the interface.


  8. Re: Can't get PPP 2.4.3 to do anything under Linux

    "Chris Nelson" writes:
    > > Bingo! "modem" seems wrong. Shouldn't that be "local". (Though this
    > > same configuration works on my older system with PPP 2.4.2.)

    >
    > Changing "modem" to "local" in /etc/ppp/options gives:


    It sounds to me like something is wrong with that serial port or with
    the wiring.

    Try also "nocrtscts" to disable hardware flow control, at least for
    now.

    > Jan 1 01:26:33 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    > Jan 1 01:26:36 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    > Jan 1 01:26:39 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    > Jan 1 01:26:42 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]


    Other than the _really_ odd text corruption, which I'll just blame on
    your non-emacs posting software for now ;-}, that looks normal. Pppd
    is now sending data out the serial port. Nothing is arriving on the
    serial port, so either PPP isn't running on that peer system or the
    underlying driver or physical link is broken.

    At a guess, the driver you're using isn't completely compatible with
    the kernel you have. It isn't some third-party add-on, is it?
    Drivers notoriously need recompilation for each kernel version on
    Linux because there's no stable DDI/DKI.

    --
    James Carlson, KISS Network
    Sun Microsystems / 1 Network Drive 71.232W Vox +1 781 442 2084
    MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677

  9. Re: Can't get PPP 2.4.3 to do anything under Linux

    James Carlson wrote:
    > "Chris Nelson" writes:
    > > > Bingo! "modem" seems wrong. Shouldn't that be "local". (Though this
    > > > same configuration works on my older system with PPP 2.4.2.)

    > >
    > > Changing "modem" to "local" in /etc/ppp/options gives:

    >
    > It sounds to me like something is wrong with that serial port or with
    > the wiring.


    Except that the same cable works between my old systems.

    > Try also "nocrtscts" to disable hardware flow control, at least for
    > now.


    I'll try that. Thanks.

    > > Jan 1 01:26:33 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    > > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    > > Jan 1 01:26:36 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    > > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    > > Jan 1 01:26:39 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    > > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    > > Jan 1 01:26:42 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    > > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]

    >
    > Other than the _really_ odd text corruption, which I'll just blame on
    > your non-emacs posting software for now ;-},


    That must be it. ;-)

    > that looks normal.


    Thanks.

    > Pppd
    > is now sending data out the serial port. Nothing is arriving on the
    > serial port, so either PPP isn't running on that peer system or the
    > underlying driver or physical link is broken.


    I found that the PPP server _had_ given up but even when I restart it,
    it doesn't work. I have some reason to believe that the driver is
    deficient (though I'd be led to believe it was sufficient for my
    immediate purposes). I'll try nocrtscts and if that doesn't work, I'll
    look into the driver.

    > At a guess, the driver you're using isn't completely compatible with
    > the kernel you have. It isn't some third-party add-on, is it?
    > Drivers notoriously need recompilation for each kernel version on
    > Linux because there's no stable DDI/DKI.


    Thanks.


  10. Re: Can't get PPP 2.4.3 to do anything under Linux

    "Chris Nelson" writes:

    >James Carlson wrote:
    >> "Chris Nelson" writes:
    >> > > Bingo! "modem" seems wrong. Shouldn't that be "local". (Though this
    >> > > same configuration works on my older system with PPP 2.4.2.)
    >> >
    >> > Changing "modem" to "local" in /etc/ppp/options gives:

    >>
    >> It sounds to me like something is wrong with that serial port or with
    >> the wiring.


    >Except that the same cable works between my old systems.


    >> Try also "nocrtscts" to disable hardware flow control, at least for
    >> now.


    >I'll try that. Thanks.


    >> > Jan 1 01:26:33 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    >> > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    >> > Jan 1 01:26:36 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    >> > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    >> > Jan 1 01:26:39 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    >> > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]
    >> > Jan 1 01:26:42 Test3 daemon.info pppd[238]: sent [LCP ConfReq id=0x1
    >> > syncmap 0x0> agic 0x3fea5345> comp> ccomp>]


    It is sending out but getting no reply.

    OK, you have to remember that ppp is a two way protocol, and thus you must
    also have pppd running at the remote end. Also at the remote end it needs
    to be listening and waiting to get a request from this end.

    Thus, at the remote end run
    pppd silent debug /dev/tty???
    (Are you really sure that ttyAM0 is the serial port which you have the
    cable plugged into?)

    They after you started pppd that way on the remote system, run
    pppd debug tty???

    on this side.
    Note that you should in /dev/syslog.conf have a line
    daemon.*;local2.* /var/log/daemonlog
    and after inserting in run
    killall -1 syslogd
    on both machines.

    This will put the debugging info into /var/log/daemonlog

    Look at the log on both machines. If the log on the far machines seens
    nothing, make sure that the serial ports and cable work.
    on the far machine run
    cat /dev/tty??
    and on the local machine run
    echo Hello /dev/tty??

    Does anything, even garbage, come out on the remote machine? If it is
    garbage you probably have a rate mismatch between the two serial ports


    So far all the evidence is that
    a) No pppd is running on the remote machine to link with this one.
    of
    b) your serial ports are broken, you cable is defective, or some other
    physical problem.



    >>
    >> Other than the _really_ odd text corruption, which I'll just blame on
    >> your non-emacs posting software for now ;-},


    >That must be it. ;-)


    >> that looks normal.


    >Thanks.


    >> Pppd
    >> is now sending data out the serial port. Nothing is arriving on the
    >> serial port, so either PPP isn't running on that peer system or the
    >> underlying driver or physical link is broken.


    >I found that the PPP server _had_ given up but even when I restart it,
    >it doesn't work. I have some reason to believe that the driver is
    >deficient (though I'd be led to believe it was sufficient for my
    >immediate purposes). I'll try nocrtscts and if that doesn't work, I'll
    >look into the driver.


    >> At a guess, the driver you're using isn't completely compatible with
    >> the kernel you have. It isn't some third-party add-on, is it?
    >> Drivers notoriously need recompilation for each kernel version on
    >> Linux because there's no stable DDI/DKI.


    >Thanks.



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