SUMMARY: ppp dropping line

From: Robert L. Spence (bspence@devtech.devtech.com)
Date: Wed May 31 1995 - 10:06:12 CDT


Sun Managers,

My original request is at the end of this message.

I'm sending this summary out a little prematurely, as I have not had the time
to completely test out the different theories....but I should at least thank
all who replied. THANKS!!!!!!! ;)

This is the kind of problem one can spend many, many, many hours on and still
not get it completely resolved.

When (if) I get this problem resolved, I will post another SUMMARY letting all
know what solved my problem. It's a little difficult to fix a problem when
you cannot reproduce it on demand, which is what seems to be happening here.

Thanks again....
Bob

--------------------------------------------------------
Srinivasa R. Yalavarthy:
        I think there is no remedy for that problem at this point. I have
        experienced the same problem in Solaris 2.4 also. No matter how big
        is the time out period in asppp.cf file the line will be dropped.
        So I've put a cron job that pings the remote machine every 5 mts.
        After doing that my ppp is straight up for the last 45 days w/o a
        problem. You may wanna give a try for that.

--------------------------------------------------------
Stephen Schaefer - Imonics Consultant:
I saw similar behavior working with a NetBlazer 2500 connected to a
Boca V.FC, with a negotiated rate of 9600 bps. 90+% of the packets to
the machine with the NetBlazer just disappeared, although all
indications from snoop, etc., were that nearly all the packets from
the NetBlazer made it through fine. The behavior went away when I
replaced the NetBlazer with a supraFAX modem, nor have I seen the
behavior with other Boca's or with an ATT model.

--------------------------------------------------------
Michael Ramchand Owner:
I had a similar problem once: the ppp connection looked good and the line was up, but no data.

I solved the problem by changing the modem. I suspect that it was a flow control problem, and that the modem was getting into a state where it was not sending data anymore.

Make sure that your cabling (straight 25 pin) is good, and that your modem is doing hardware handshaking and XON/XOFF pass-thru.

At least thats what worked for me.

Modems tend to be pretty annoying as each on has different terminology for the same thing.

--------------------------------------------------------
Mr S J Elliott:
We too had a lotf of problems with PPP and solaris 2.3
we ended up buying Marning Star PPP, which works a lot
better

--------------------------------------------------------
Sean Steppie:
I had a similar problem, but what happened here was that it droped the
line after about 45 seconds - in fact you could time it. What I found
to solve it was making the modem communicate in asynchronous mode ie
AT&Q0.

--------------------------------------------------------
S. D. Raffensberger:
It sounds like you have PPP working okay. There seem to be
two things you should be looking for.

1. Something is causing the modem to go on hook.
2. Something is keeping the computer from detecting it.

If you can get the computer to detect when the modem goes
away, you will be better able to find out why it does.

Make sure you have wiring for DSR and CD in your cable.
Make sure you have tty?-ignore-cd set to off in your
PROM settings. Make sure your modem is set up to assert
CD and DSR at the appropriate times.

PPP should then log when the modem goes away. Morningstar's
PPP will even automatically re-establish the connection.

I don't know enough about your setup to tell what might be
causing the modem to hang up. The only thing I've experienced
like that was intentional ... the modem was set to hang up after
15 minutes of idle time. This doesn't sound like it applies
to you.

--------------------------------------------------------
Scott Kamin [Sun Denver SE]:
It sounds like a symptom I've seen before. Your Internet
provider may have a time-out set so that the connection is dropped
at their end if they don't see any activity from you in a certain
period. When you're doing an ftp, all the activity is one way,
there's no response back from your end.

Try setting a program in the background that does a ping to an
Internet host followed by a sleep 30.

Then try your large ftp.

--------------------------------------------------------
John Stewart:
What is on the other side of the PPP connection? I had this same
problem with an SGI running their PPP and it was all due to a problem
on the dialup switch.

----- Begin Included Message -----

>From bspence Tue May 2 10:32:47 1995
To: sun-managers@ra.mcs.anl.gov
Subject: ppp dropping line
Cc: kleining@devtech
Content-Type: X-sun-attachment
Content-Length: 16406

Sun Managers,

SYSTEM INFORMATION:
        System: Sun Sparc 5
        Release: 5.3
        Kernel architecture: sun4m
        Application architecture: sparc
        Hardware provider: Sun_Microsystems
        Domain:
        Kernel version: SunOS 5.3 Generic 101318-70 February 1995

We are having a problem with our ppp connection. The ppp connection can be
established without a problem, and we can ping internet hosts, run Mosaic, and
use anonymous ftp (for a while).

But when we start trying to pull down information, either through Mosaic or
ftp, the connect seems to drop. I can see by the modem that it still
thinks that a connection exists, and if I try pinging a host, I can see the
send data light blinking, but no data is being send back to the modem. I can
verify this behavior with snoop.

I have looked in SunSolve, and found some instances where the ppp connection is
lost, but the symptoms do not match our situation.

I have included the patch listing for this system, as well as a description of
the ppp packages being used.

Is there anyone else out there experiencing this problem? Any suggestions?

I will summarize.

Regards,
Bob

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