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Clifford Kite
*nix forums Guru Wannabe
Joined: 03 Mar 2005
Posts: 119
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 Posted: Fri Jan 27, 2006 6:01 pm Post subject:
Re: HELP: pppd won't answer/authenticate my dial-in
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mark.bergman@thales-is.com wrote:
| Quote: | James Carlson wrote:
1. Set up the modem so that it has a locked DTE rate.
I had tried setting the modem speed. It has one option (&Un) for a
minimum speed and another (&Nn) for a maximum speed, but if I specify a
minimum speed higher than 1200/2400, it just rejects the incoming call
(presumably because it cannot negotiate higher)
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I'd also recommend you use mgetty _and_ configure it to initialize the
USR modem with AT&F1 . That should allow modem auto-negotiation, and
the pppd speed can then likely be set to 115200 (which is the highest
a serial device using a 16550A UART can reliably tolerate - 56k * 2).
--
Clifford Kite Email: "echo xvgr_yvahk-ccc@ri1.arg|rot13"
/* Speak softly and carry a +6 two-handed sword. */ |
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James Carlson
*nix forums Guru
Joined: 23 Feb 2005
Posts: 310
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| Posted: Fri Jan 27, 2006 10:45 pm Post subject:
Re: HELP: pppd won't answer/authenticate my dial-in
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mark.bergman@thales-is.com writes:
| Quote: | James Carlson wrote:
1. Set up the modem so that it has a locked DTE rate.
I had tried setting the modem speed. It has one option (&Un) for a
minimum speed and another (&Nn) for a maximum speed, but if I specify a
minimum speed higher than 1200/2400, it just rejects the incoming call
(presumably because it cannot negotiate higher)
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You need to set the DTE rate, not the DCE rate. The commands you're
talking about set the DCE rate.
Modern modems have two "sides" -- one is the serial link, and the
other is the telephone connection. They're not really related to each
other, because the encoding protocols on the telephone side are fairly
sophisticated. What this means is that the modem does (and has to do)
data buffering and flow control.
Thus, there are two data rates involved. The one you care about here
is the one on the serial side.
--
James Carlson, KISS Network <james.d.carlson@sun.com>
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 |
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jpd
*nix forums Guru
Joined: 22 Feb 2005
Posts: 877
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| Posted: Sat Jan 28, 2006 3:31 pm Post subject:
Re: HELP: pppd won't answer/authenticate my dial-in
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Begin <1138298261.007434.120630@g49g2000cwa.googlegroups.com>
On 2006-01-26, mark.bergman@thales-is.com <mark.bergman@thales-is.com> wrote:
| Quote: | (I now need to look at why the modems are connecting so slowly! They
are US Robotics 57.6K modems, but probably rather old! We are running
them through two internal phone connections at our company exchange.
We may try and find some other modems).
|
Apart from all the other suggestions, I'd like to note you say you're
using a PABX. Those are likely built for voice only, and may not provide
a suitable channel for the modem to use. I'd say to not point at your
modems before you have independent confirmation the PABX provided
channel is indeed suitable for POTS data transfer.
The rather preposterous CONNECT 1200/and/a/xmas/tree message seems to
indicate that the modems tried and failed due to bad line, not that they
are too old or otherwise incapable. Assuming that you did configure them
correctly and did not force this extremely low speed by accident or
intention. Given the right commands it is probably possible to extract
proof of either out of your USR modems.
--
j p d (at) d s b (dot) t u d e l f t (dot) n l .
This message was originally posted on Usenet in plain text.
Any other representation, additions, or changes do not have my
consent and may be a violation of international copyright law. |
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mark.bergman@thales-is.co
*nix forums beginner
Joined: 23 Jan 2006
Posts: 12
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| Posted: Mon Jan 30, 2006 6:25 pm Post subject:
Re: HELP: pppd won't answer/authenticate my dial-in
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James Carlson wrote:
| Quote: | mark.bergman@thales-is.com writes:
So just to confirm, the speed parameter I pass to pppd must exactly
match the speed that the modems are talking at?
Yes.
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OK, I have now had some limited success!
As I mentioned, I was having problems getting the modems to connect at
high speeds.
Firstly, I put the modems between 2 PCs, using Hyperterminal on each at
57600, and dialled manually - Hey Presto I had a 57600 connection. -
this eliminated concerns about our internal telephone exchange.
Secondly, I put the receiving modem back to the Digital Unix box, and
ran "tip 57600" (with pppd not running) - modems connected at 1200.
I examined stty for the port, and its speed was 1200.
I killed the connection, and with tip still open, set the port speed
with stty to 57600.
Dial in again, and connection at 57600 - this shows that the port speed
must be set to 57600 to get the modems to connect at this speed.
Thirdly, I closed tip. Port speed went back to 1200.
I reinstated pppd (in /etc/inittab) - port speed still at 1200.
I used stty to set speed to 57600, and dialling in from the PC I
sometimes got a successful ppp connection, but many times the pppd died
and restarted (after I set the port speed), losing the speed setting,
so I was battling trying to set the speed and keep pppd running.
So, questions at the moment:
1) Should pppd be setting the port speed (in the same way that stty
does)
2) If I set the port speed with stty, should it get reset (e.g. if a
process that has the port open closes it or dies)?
3) Is there anyway to retain the port speed (this is a XP1000 box
running Digital Unix 4.0F)
(We do have this working to some equipment on another site, and I am
trying to recreate it on some support equipment. On site the receiving
modem is a Multitech (rather than a US Robotics), so I am going to try
and obtain a Multitech modem to see if that is any better.)
Mark
mark . bergman @ thales - is . com |
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James Carlson
*nix forums Guru
Joined: 23 Feb 2005
Posts: 310
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| Posted: Mon Jan 30, 2006 6:42 pm Post subject:
Re: HELP: pppd won't answer/authenticate my dial-in
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mark.bergman@thales-is.com writes:
| Quote: | So, questions at the moment:
1) Should pppd be setting the port speed (in the same way that stty
does)
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"Should?"
It does set the speed in the same way as stty does when given a speed
as one of the options. It doesn't touch the current line speed when
no speed option is set. See the pppd man page.
| Quote: | 2) If I set the port speed with stty, should it get reset (e.g. if a
process that has the port open closes it or dies)?
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Typically, yes.
| Quote: | 3) Is there anyway to retain the port speed (this is a XP1000 box
running Digital Unix 4.0F)
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I don't think that's the real problem, as I've stated in previous
posts.
The real problem is configuring your modem properly to lock the DTE
rate. See the reference manual for your modem.
According to several web sites I searched, USR modems usually use
"AT&B1" to lock the DTE rate. You would "tip" in at 57600 and issue
this command to lock the rate.
If your modem doesn't support that command for some reason, then you
might have to set dip switches. Very old modems were like that.
Some old consumer-grade modems can't lock the rate at all. If you
have one of those horrible beasts, then you'll need to use the pppd
"init" option, as I previously described.
--
James Carlson, KISS Network <james.d.carlson@sun.com>
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 |
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mark.bergman@thales-is.co
*nix forums beginner
Joined: 23 Jan 2006
Posts: 12
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| Posted: Tue Jan 31, 2006 2:35 pm Post subject:
Re: HELP: pppd won't answer/authenticate my dial-in
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| Quote: | The real problem is configuring your modem properly to lock the DTE
rate. See the reference manual for your modem.
According to several web sites I searched, USR modems usually use
"AT&B1" to lock the DTE rate.
|
The modem does support that command but it didn't help; in fact that is
the default.
I have now obtained a Multitech modem which I am using at the receiving
UNIX end. (It is a Multitech modem that works on our site machine,
although I don't know if it is the same model of modem or not. My PC
modem now connects straight away at 57600 no problem, and stty on the
UNIX end shows 57600.
However, my PPP is now not connecting at all. Looking in the debug,
there is no exchange of LCP, i.e. no debug entries at all after the ppp
starts up.
I tried removing the "silent" ppp option, and I see the LCP Configure
Requests being sent in the debug file ("sent output frame of 58
bytes..." in kernel syslog file) and timing out.
Before (when using USR modem) I also got "missed ALLSTATIONS (0xff),
got 0xf3" which led you to the mismatched speed, but I'm not seeing
that this time - just the "sent output frame" messages.
Puzzled
Mark
mark . bergman @ thales - is . com |
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James Carlson
*nix forums Guru
Joined: 23 Feb 2005
Posts: 310
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| Posted: Tue Jan 31, 2006 2:55 pm Post subject:
Re: HELP: pppd won't answer/authenticate my dial-in
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mark.bergman@thales-is.com writes:
| Quote: | I tried removing the "silent" ppp option, and I see the LCP Configure
Requests being sent in the debug file ("sent output frame of 58
bytes..." in kernel syslog file) and timing out.
|
That's a separate problem. I'm pretty sure this was discussed earlier
-- you almost certainly don't want to use "silent."
| Quote: | Before (when using USR modem) I also got "missed ALLSTATIONS (0xff),
got 0xf3" which led you to the mismatched speed, but I'm not seeing
that this time - just the "sent output frame" messages.
|
At a guess, you still have modem configuration problems. It's hard to
tell at this point what those problems might be.
(Common problems include having a modem that defaults to software flow
control rather than hardware flow control, and a port set to 7 data
bits rather than 8. Those are just wild guesses, though.)
--
James Carlson, KISS Network <james.d.carlson@sun.com>
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 |
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Unruh
*nix forums Guru
Joined: 22 Mar 2005
Posts: 1166
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| Posted: Tue Jan 31, 2006 4:45 pm Post subject:
Re: HELP: pppd won't answer/authenticate my dial-in
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mark.bergman@thales-is.com writes:
| Quote: | James Carlson wrote:
mark.bergman@thales-is.com writes:
So just to confirm, the speed parameter I pass to pppd must exactly
match the speed that the modems are talking at?
Yes.
OK, I have now had some limited success!
As I mentioned, I was having problems getting the modems to connect at
high speeds.
Firstly, I put the modems between 2 PCs, using Hyperterminal on each at
57600, and dialled manually - Hey Presto I had a 57600 connection. -
this eliminated concerns about our internal telephone exchange.
Secondly, I put the receiving modem back to the Digital Unix box, and
ran "tip 57600" (with pppd not running) - modems connected at 1200.
I examined stty for the port, and its speed was 1200.
I killed the connection, and with tip still open, set the port speed
with stty to 57600.
Dial in again, and connection at 57600 - this shows that the port speed
must be set to 57600 to get the modems to connect at this speed.
Thirdly, I closed tip. Port speed went back to 1200.
I reinstated pppd (in /etc/inittab) - port speed still at 1200.
I used stty to set speed to 57600, and dialling in from the PC I
sometimes got a successful ppp connection, but many times the pppd died
and restarted (after I set the port speed), losing the speed setting,
so I was battling trying to set the speed and keep pppd running.
|
It sounds to me like Digital Unix is messing with the port. Ie, each time
it is reset it also resets the speed.
Yes, you can give pppd the port speed to run at.
Just put in the number
pppd .... 57600
| Quote: | So, questions at the moment:
1) Should pppd be setting the port speed (in the same way that stty
does)
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Its default is 1200.
| Quote: | 2) If I set the port speed with stty, should it get reset (e.g. if a
process that has the port open closes it or dies)?
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Ask the writers of Digital Unix. Noone else has access to the source code.
| Quote: | 3) Is there anyway to retain the port speed (this is a XP1000 box
running Digital Unix 4.0F)
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tell pppd the port speed you want.
In fact with most modern modems and serial cards, a better port speed is
115200, the max speed the port can be set at. The port speed on most modems
is independent of the connection speed and because of modem compression,
should be higher than the modem to modem rate.
| Quote: | (We do have this working to some equipment on another site, and I am
trying to recreate it on some support equipment. On site the receiving
modem is a Multitech (rather than a US Robotics), so I am going to try
and obtain a Multitech modem to see if that is any better.)
Mark
mark . bergman @ thales - is . com |
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mark.bergman@thales-is.co
*nix forums beginner
Joined: 23 Jan 2006
Posts: 12
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| Posted: Wed Feb 01, 2006 12:58 pm Post subject:
Re: HELP: pppd won't answer/authenticate my dial-in
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mark.bergman@thales-is.com wrote:
| Quote: | call is answered on the UNIX box, but PPP doesn't seem to authenicate
it, and the call is terminated.
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Well, I appear to have full success now!
I'm using a Multitech modem to receive on (which gets my modems to
connect at 57600), and when doing more experimenting with a few
telephone sockets on my company's exchange, found one combination that
allows PPP to connect every time (using default modem options!)!
(I had previously tried this pair of sockets the other way round
unsuccessfully, i.e. with PC and UNIX box swapped).
I should now really go back to the pair of USR modems, or do more
experimentation with the phone sockets (go back to the reverse
combination that failed previously, etc), but I don't want to touch my
working setup in case I can't get it back again! (I've spent far too
much time on this already!)
Thanks to all who offered assistance
Mark
mark . bergman @ thales - is . com |
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