NetNews Usenet Archive 1993 #3/NN_1993_3.iso/spool/comp/sys/sgi/admin/311

Internet Message Format | 1993-01-28 | 2.9 KB

Path: sparky!uunet!contex!sam.contex.com!james
From: [e-mail] (James McQueston)
Newsgroups: comp.sys.sgi.admin
Subject: SLIP - (1)hangup and (2)"212" Dialer
Keywords: SLIP Admin
Message-ID: <[e-mail]>
Date: 26 Jan 93 20:19:25 GMT
Sender: [e-mail]
Lines: 72

I've got my slip connection working pretty well with two high-speed
modems, but I have one open problem, and one problem that I solved
that took a long time to track down and for which I don't understand
my workaround.

Question 1:

I would like to have my remote (incoming) SLIP die when its modem loses
DCD.  This would cause uugetty to re-chat with the modem and reset it
to answer the modem for the next user.  What happens instead is that the
modem has hung up the phone, and SLIP keeps trying to talk to the modem
in its command mode.  Although SLIP seems to know that something is wrong,

    sl0: bad checksum
    ...
    sl0: bad checksum
    sl0: bad checksum
    sl0: dropping babble
    sl0: bad checksum
    sl0: bad checksum
    ...

it never gives up.  If I become root and killall -HUP SLIP, it ignores it.
Then only way to get rid of the incoming SLIP seems to be to kill it with
something more substantial.

Is there something I don't know, or can do, so that SLIP will die on the
tty-generated HUP signal?  Or is this the way SLIP is supposed to work
for some weird reason?  Here are snippets of some important files:

#/etc/passwd:
slip-garbo::0:0:Remote SLIP from garbo:/:/usr/etc/remoteslip

#/etc/inittab:
t1:23:respawn:/usr/lib/uucp/uugetty -DNt5 -iDSIin,conn ttyf1 dx_38400 #DSIin

#/usr/etc/remoteslip
case $USER in
...
slip-garbo)
    echo User is slip-garbo >> /tmp/slip.$$
    exec /usr/etc/slip -p comp -i -r garbo -ddd
    ;;
...
esac

Question 2:

When writing a /usr/lib/uucp/Devices line for outgoing SLIP, I find that
it will not work on /dev/ttyf1 unless the "built-in" dialer-token pair
"212 x" is given.  Of all the pages and pages of documentation on SLIP
and UUCP in the IRIX Site Admin. Guide and IRIX Network Admin. Guide,
the only reference to this is in the latter on page 7-4, where it says
that
    The correct format for a line appropriate for SLIP in
    /usr/lib/uucp/Devices is:
        ACUSLIP device null speed 212 x dialer

It never explains why.  The man page for SLIP never mentions this fact.
And if you don't do it, the error you get from SLIP -ddd is a timeout
when trying to access the device.

Can someone explain what the "212" dialer is, what the "x" token for it means,
and why SLIP breaks when you don't use it.  Furthur, can someone at SGI
add this explanation to the man page for SLIP, and convince the Documentation
people to explain this a little more in section 7.2.2 of the Network Admin.
Guide?
--
-----
James H. McQueston        [e-mail]
Xyvision Color Systems, Inc.    [phone] x 5523 (office, voicemail)
Wakefield MA 01880-1291        [phone]        (lab phone direct)