Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!decwrl!bacchus.pa.dec.com!decatl!decatl!thomas
From: thomas@decatlalf.dec.com (Elgin Thomas)
Newsgroups: comp.unix.ultrix
Subject: Re: Reassigning IP-adress to boot clients
Keywords: IP reassign dec3100 ultrix
Message-ID: <1990Aug7.183447.8848@decatl.dec.com>
Date: 7 Aug 90 18:34:47 GMT
References: <1990Aug7.111645.25785@diku.dk>
Sender: news@decatl.dec.com (USENET News System)
Reply-To: thomas@decatlalf.dec.com (Elgin Thomas)
Distribution: comp
Organization: Digitial Equipment Corporation, Alpharetta, GA
Lines: 76


>At our site we have several DEC3100s which all boot from a central server
>(also a DEC3100). We have a central administration of our LAN, and they want
>us to assign different IP-addresses to some our machines (all of them 
>boot-clients).

>Unfortunately it is unclear to me how this is done. Actually we don't even
>know where the machine gets its own IP-address. I think I know that it gets
>it through ARP from the boot server, but where does *it* get it? -- There
>must be a file somewhere that contains information about which clients get 
>which addresses. (Surely it can't be /etc/hosts ? -- I have tried that, and
>doesn't seem to work).

>Our local DEC has so far been unable to provide an answer to this question,
>which is of course totally unacceptable (and perfectly in line with our
>general experiences with DEC Denmark).

>The net is my only hope, I'm afraid, so please help me someone!

>Thanks in advance.

The DMS clients recieve their IP-address and other information from the server
via the secondary loader.  On the server do the following:

/etc/getnode clientname

node =          CLIENT
        hardware address = 08-00-2b-0e-dd-ee
        load file = netloadudt030.sys
        secondary loader = clients/client
        tertiary loader = vmunixudt030.sys

The file client is located in /usr/lib/dnet/clients.  This directory
also contains the
C source for the file:

/* Client packet for client client
   Copyright (C) 1988
   DIGITAL Equipment Corp.
   Maynard, Massachusetts
*

#include <sas/mop.h>
struct netblk nblk={			
        "server",			/* server hostname (boot server)*/
        0x1048003a,			/* server IP address (boot server)*/
	"client",			/* client hostname */
	0x10480041,			/* client IP address */
	0x104800ff,			/* broadcast address */
	0xffffff00,			/* network mask address */
        0,				/* swap file system type */
        1,				/* root file system type */
        0,				/* swap size in 1/2 Meg units */
        0,				/* dump flag 0-disabled, 1-enabled */
        "dummypath",			/* root filesys descriptor */
        "dummypath",			/* swap file descriptor */
        ""				/* for later use */
};

To change the client IP address you can edit the appropiate fields and then
recompile the C source file for the client.  But, perhaps the easiest way is
to use the /etc/dms script file to modify a client.  This script will
edit the file
and rebuild it automatically.

The only other file that needs to be changed is the /etc/hosts file on
the server.
This file needs to be modified to reflect the new host numbers before running
the /etc/dms script.

Hope this helps,

Elgin Thomas 
Digital Equipment Corp.
Customer Support Center
Ultrix Support Group