Need some 'wizard' help with our ethernet network configuration

Bob Erickson bob at anwar.UUCP
Sun Aug 5 02:49:02 AEST 1984


I have just installed our ethernet system connecting our VAX 11/750
and our Pyramid 90x systems.

Everything is working quite well except for a few problems which
are non-critical.  I have spent a little time tracing these problems
down but now turn to the wizards on this net for a little insight
before I go whole hog.

We are using Interlan ethernet boards on both systems which are referred to
on both systems as 'il0'.  After connecting the system, everything worked
fine.  rlogin, rsh, rcp, ftp, and telenet all worked as stated.  The commands
that didn't work were ruptime, and rwho.  But only on the VAX they didn't work.
They worked fine on on the Pyramid, but only reported info about the Pyramid.

I traced it down to the fact that the 'rwhod' process on our VAX determined
that there were no hardware interfaces present with 'BROADCAST' ability and
therefor never sent out or received messages.

In the function 'configure' in rwhod.c, a check is made to see if the
field 'ifr_flags' has the bits 'IFF_BROADCAST|IFF_POINTOPOINT' set.
If they are not set, the interface is ignored.  So now I have no reason
to suspect a fault in rwhod.  Next I compared the ifconfig output from
both systems and got the following result.

Working system (Pyramid):
	/etc/ifconfig il0
il0: 193.0.9.72 flags=63<UP,BROADCAST,NOTRAILERS,RUNNING>

Non Working System (VAX):
	/etc/ifconfig il0
il0: 193.0.9.22 flags=21<UP,NOTRAILERS>

As expected, the BROADCAST flag was not set.  Time to go rummaging through
the driver, where I found that this flag is set in the routine 'ilsetaddr'
in the interlan driver if_il.c.  This routine I believe is called when you
run the /etc/ifconfig command in the rc.local file.  The /etc/ifconfig 
commands are the same on both systems except for the host names of course.

Just to make sure no other process was unsetting this flag I have the 
following two lines in my rc.local file.

/etc/ifconfig il0 `hostname` up -trailers arp	# configure the host
/etc/ifconfig il0 >/dev/console

Where I still get the result printed at the console:

il0: 193.0.9.22 flags=21<UP,NOTRAILERS>

Here's where you come in.

Who could possibly be unsetting the 'IFF_BROADCAST' flag between those two
commands ?

What am i doing wrong ?  If anything I would expect this to work on the VAX
system since thats the main release of 4.2BSD.

Other than this simple problem, the net is working quite well, and installation
was quite straightforward.

If you feel the answer might be generally useful, post it, else direct mail 
please.


						        Thanx

========================================================== Be

Company: 	HHB-Softron
UUCP address:	{ihnp4,decvax,allegra}!philabs!hhb!bob



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