[lug] Dialup modems and Linux

[Justin-lists]

> That minicom can dial the modem and get a connection is a good 
> thing.  It also probably explains why you don't get anything printed 
> in the logs.  
> (There really is nothing printed in the logs right?) As far as the Linux
> system is concerned there isn't a problem.

Yes, nothing printed in the logs. Minicom doesn't even seem to realize that 
the modem hangs up. I can physically hear the modem hangup, but minicom's 
counter just keeps ticking until the connection attempt times out. Where it 
then restarts the dialing procedure.

> What is particularly interesting is that you are getting nothing in the
> minicom window.  That to me means that the problem you are having is
> between the modem and the dialup server and not between Linux and the
> modem control.  Either the modem settings don't match what the server
> expects (usually you'd get some unreadable garbage in this case 
> though), or the server isn't answering you back for whatever reason.  

I am thinking the same thing. I know some isps prompt for the login and 
password in a certain fashion. Like "sername" for the user and "assword" for 
the password or something to that affect. Now that I think of that, I recall 
setting up dialup in the past in linuxconf. I remember configuring linux to 
look for "sername", once it saw that it would pass the username to the 
server, then wait for "password" or whatever and then send the password. But 
I don't know how to configure that with just minicom...

> Do you have a manual for this modem and have you checked the
> initialization string that is sent to the modem?  That would 
> configure things like flow control, how the modem handles 
> negotiation of the dial link speeds, etc..  Have you been able to 
> connect to this server before, perhaps running one of these modems 
> under MSWindows?  If so, you may be able to take a look at what that 
> software is using in its initialization string.
> 
> The kind of behavior you are describing could occur if the modem settings
> don't match what the dialup server expects.  Linux could control the 
> modem and dial it, but the modem wouldn't be able to negotiate the 
connection
> protocol with the server (incompatible speeds or incompatible compression
> algorithms, etc.).  That would probably result in a dropped 
> connection attempt, and relatively little logging information.  If 
> you don't see any kind of activity in the minicom screen then you 
> never actually get a communications link established with the 
> server.  It never asks for a login and so your system never even 
> gets to the authentication stage.

I did go out on the internet and find the initialization string for this 
particular modem. I put the string in minicoms config when I was first trying 
it, but I don't think I had it configured to use that init string lastnight. 
Shoot, maybe I'll try to grab linuxconf and use netcfg to configure the ppp 
again, hehe. 

> (One thing is nagging in the dark recesses of memory about a newer login
> procedure that some dialup servers were starting to use.  That might 
> not create the classical login challenge used by chat scripts, but I 
> can't quite place what that might be?  Perhaps someone knows, or 
> perhaps this is one of those vague not quite correct 
> recollections...?)
> 
> - Wayde
>   (wallen at lug.boulder.co.us)
> 
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