From: jim@jagubox.gsfc.nasa.gov (Jim Jagielski)
Subject: Re: SLIP
Keywords: SLIP
Reply-To: jim@jagubox.gsfc.nasa.gov (Jim Jagielski)
Organization: NASA/Goddard Space Flight Center
Date: Thu, 30 Jul 1992 14:50:56 GMT

rob@cbnewsk.cb.att.com (rob) writes:

>I am having a heck of a time getting SLIP to work.
>My setup: A/UX 3.0 configured with bnet - MacIIci 8/160 - Telebit T3000
>modem with hardware-handshake cable.
>The problem: I want to use my Mac as a SLIP client to an HP9000/382
>running HP/UX 8.0 and configured as a SLIP server. I can cu(1) and log
>into the HP with no problem. I can start ppl(1) [<== The HP SLIP interface]
>ok, and it tells me the protocol is started. I can then run slattconf(1) on
>the Mac and it returns 'sl0' as expected. 'netstat -r' on the Mac indicates
>that the routing tables are as they should be.  'netstat -Isl0 10' shows
>that there are input and output packets flowing through 'sl0'.

>BUT.....
>If I try to do anything with the SLIP connection (i.e. - telnet, ftp,
>ping) nothing happens! I can 'ping' my local system via its system name
>as shown in /etc/hosts (rather than 'loop') and get results, but when
>I try to ping the SLIP server I get no response.

>Is there something obvious I can try to attempt to determine what's going on?
>Since netstat indicated input packets are arriving it would be nice
>if I could snoop at the packets to see their headers, but I don't see any 
>A/UX support for that. I fear that I may have something within A/UX
>configured incorrectly such that the Mac does not recognize packets addressed
>to it.

>Any and all suggestions are welcome and will be tried. I will summarize
>all responses for the net if there is interest. Thanks in advance.....

Hmmm... well, Ron (@afsg) has ported the Berkeley Packet Filter (bpf)
package over to A/UX 3.0, so if you install it, you can snoop and
look at the packets (look for bpf on afsg.apple.com).

Have you setup nameserver and routing correctly (running named, routed,
using resolv.conf or a static route)? If this question causes you to
go "Huh? What?" then I would guess that's it.

You see (this little discussion is based on TCP/IP-Ethernet but should
be valid for CSlip as well), to use networking your Mac must also be
able to figure out what machine you mean by "foo.bar.blah". That's
the nameservers job. You can have you Mac do that function completely
or have it question real nameservers. The latter is mucho easier; all
you need is a short little file called /etc/resolv.conf that says
who those nameservers are. If you have the hosts in /etc/hosts, then
your Mac should be able to figure out who they are as well.

The other thing is that there must be some way for packets that you
generate to go out into the real world... This is the job of a router
or gateway. Again, you can tell A/UX which gateway to use ("route")
or run the routed ("routed -q") to listen for who is the right
router. Again, the later is easier; just run it from /etc/inittab.
This also allows for outside packets to reach you.

PS: If any of the above isn't valid for CSlip, then I never said it :)
-- 
==============================================================================
#include <std/disclaimer.h>

                Jim Jagielski                  NASA/GSFC, Code 734.4
          jim@jagubox.gsfc.nasa.gov             Greenbelt, MD 20771

           "The great scallop... this tatty, scrofulous old rapist,
               is second in depravity only to the common clam."