Re: Slip

[roemer@informatik.uni-frankfurt.de]

> > % /etc/slattach -t /dev/ttyb -r 128.2.111.207 
> 
> slattach does not work for me. I use the following script to attach my
> TT on my Sun.
> 
> #!/bin/sh
> #
> /etc/iflink -i sl0 -d /dev/ttya
> stty 19200 -icrnl -isig -icanon -echo -echoe -echok < /dev/ttya
> /etc/ifconfig sl0 addr 192.9.201.2 dstaddr 192.9.201.0 up
> /etc/route add 192.9.201.0 sl0
> 
> Without these stty settings, SLIP will not work properly. The machine
> will crash if you try to ping the TT from outside.

Well, slattach usually does these tty settings, too. In fact slattach
does nearly the same as the above script with one exception: It gets
the local hosts name via gethostname() and resolves the name into
an IP address using gethostbyname().

The problem with doing it this way is the following: gethostbyname()
uses one of the namservers in /etc/resolv.conf to resolve the hostname into
an IP address. But usually the nameserver is one of the hosts on the other
side of the slip link that is currently beeing established. So naturally
(because the slip link is not yet up!) the resolving fails.

If you have (in /etc/resolv.conf)
1) only one nameserver line for localhost 'namserver 127.0.0.1' or
2) multiple namserver lines and none of the namservers is reachable
   before the slip link is up (ie all namservers are on the other side
   of the slip link)
then the hostname lookup via namservers fails immediatly and the
hostname will be resolved using the /etc/hosts file (which should
hold an entry for your hostname) and all should work fine.

If you have multiple namserver lines in /etc/resolv.conf and one or more of
them are reachable but does not run a nameserver (eg. 127.0.0.1) then the
lookup will be retried 5 times (which can take up to 30 seconds) before
timing out and the lookup (and slattach) will fail completely.

Slattach makes the tty settings *after* having obtained the local hosts IP
address. So if you access your host from outside within those 30 seconds
the tty settings are not yet done and some processes may be killed...

Solution for now:
Only one namserver line in /etc/resolv.conf.

I will probably add an option to slattach which lets you specify the local
hosts IP address so no resolving is needed!

Another problem are the modem2 and serial2 ports of the TT. The will *not*
work without hsmodem -- don't ask me why...

serial1 does not work with a usual null modem, because of the missing DTR/DCD
signals.

Up until now I had no chance to try MintNet on the Falcon. If it does not
work on modem1 of the Falcon then first try hsmodem.... and send me mail
if you get it to work.

Kay.