[comp.protocols.tcp-ip] SLIP implementation questions

zjat02@trc.amoco.com (Jon A. Tankersley) (12/27/90)

We're looking at SLIP for connecting remote PC systems with our UNIX boxes
and I've got some questions on implementation:

Setting up the UNIX hosts with sliplogin (from slip4.0) is not a big problem,
but SunOS 4.0.3 doesn't allow it easily from ttytab.  This isn't a big problem
either, but I have a limited number of ports to connect to via slip.  Has
anyone tried to implement sliplogin as part of the cycle on the getty baud
rate cycle?  I was thinking of having sliplogin first, then break for the
different speeds of getty.

On a PC, in this case with an MNP modem (19200/9600/...) running PC/TCP
software, starting up slip, how do I get the modem to dial the proper number?
I also have some special commands and passwords to get through some security
to set up the connection.  Is that possible?  I tried using procomm to
call, then try and connect, but either dropping or not dropping procomm didn't
let slip work.  And none of the PC/TCP utilities work without a connection in
place.  Any ideas?

Is there any way to assign the SLIP IP addresses on the fly for the remote
connections.  We're going to have N PC's and only M connections (M<N) but
not everyone will be calling in at the same time.  I'd rather not have to
have the users know M IP address to try, I'd rather let them establish a
connection and get the IP address of the SLIP login.  Is that possible or
against the protocol?

Is there a better way?  PPP doesn't seem to be fully operational on SunOS
4.0.3 or 4.1* yet, at least not without source license.

Please email and I'll post a summary of the responses.

Thanx
-- 
-tank-
#include <std/disclaimer.h>		/* nobody knows the trouble I .... */
tank@apctrc.trc.amoco.com    ..!uunet!apctrc!tank

bushell@HAWK.NSTN.NS.CA (Tom Bushell) (12/28/90)

tank@apctrc.trc.amoco.com (Jon A. Tankersley) writes:

>We're looking at SLIP for connecting remote PC systems with our UNIX boxes
>and I've got some questions on implementation:
> .........
>On a PC, in this case with an MNP modem (19200/9600/...) running PC/TCP
>software, starting up slip, how do I get the modem to dial the proper number?
>I also have some special commands and passwords to get through some security
>to set up the connection.  Is that possible?  

We recently had a similar problem when we needed to offer dial up Internet access
for some of our NSTN (Nova Scotia Technology Network) customers.  We were
forced to write some C programs that dialed the phone and handled the logon
sequence to our terminal server.


>I tried using procomm to call, then try and connect, but either dropping or not
>dropping procomm didn't let slip work.  And none of the PC/TCP utilities work
>without a connection in place.  Any ideas?

I'm surprised this didn't work for you.  I've successfully connected with both
NCSA Telnet and Phil Karn's KA9Q software using Procomm.

Also, it turns out that KA9Q has a dialer.  We discovered this by looking at the
source code - nowhere is it mentioned in the documentation.


>Is there any way to assign the SLIP IP addresses on the fly for the remote
>connections.  We're going to have N PC's and only M connections (M<N) but
>not everyone will be calling in at the same time.  I'd rather not have to
>have the users know M IP address to try, I'd rather let them establish a
>connection and get the IP address of the SLIP login.  Is that possible or
>against the protocol?

We handled the dynamic assignment of IP addresses by having our C program
capture the address assigned by the terminal server during the login sequence, and
used an AWK script to modify the configuration files for the applications before
we ran them.  We used Rob Duff's pc AWK, which is available from SIMTEL.


Hope this helps.

-Tom

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