2ND SUMMARY : Suninstall across a gateway

From: Mathew BM LIM (M.Lim@anu.edu.au)
Date: Fri Mar 20 1992 - 00:15:49 CST

There were several more responses to my original posting regarding running
suninstall across a gateway which arrived after my last summary. Some
were interesting enough to warrent a second summary, so here it is again.

My original query :
>I am posting this for a third party, this is probably a FAQ but here it is :
>How does one run suninstall (SunOs 4.1) if the tape host is on another subnet ?
>For that matter, how does one boot a diskless Sun across subnets ?
>Thanks in advance.


From: Eddie Brown <eddieb@ERC.MsState.Edu>

I have a friend who figured out a real EASY way to
do it. What you do is once you boot the miniroot and
are at the single-user prompt, go ahead and MANUALLY
do an ifconfig and add a default route for the gateway
machine. Then find the ifconfig binary and rename it
to something else. Then replace it with some little
dummy executable file, like a shell script that does
an echo.

Now, when you run suninstall and it tries to do
that "Configuring interfaces" routine, nothing
will happen and your original manual ifconfig and
routes will still be in place so you can talk
out of the subnet. It's a snap to do.


        ( = your machine / = gateway )
1. Boot miniroot

2. At SU prompt:

  ifconfig le0 netmask broadcast

  route add default 1

3. Now ping the gateway to make sure it works.

4. Find the ifconfig binary (I think it's in /etc)

5. Rename it and replace it with a dummy file

        mv ifconfig ifconfig.exe
        cat > ifconfig
        echo "Happy"

        chmod 755 ifconfig

6. Now run suninstall just like normal. When it goes to
   configure the interfaces it should just print "Happy"
   and be able to talk out of the subnet.

Sorry, I wasn't able to send this to you earlier.


            Eddie Brown Email: eddieb@erc.msstate.edu
       System Administrator USmail: P. O. Box 6176
 Microsystem Prototyping Laboratory Miss. State , MS 39762
    Mississippi State University Phone: 601-325-1607
                                          Fax: 601-325-7692


From: gdmr@dcs.edinburgh.ac.uk

In article <29639@skye.dcs.ed.ac.uk>, you write:
> How does one run suninstall (SunOs 4.1) if the tape host is on another subnet ?

Just exit suninstall after it boots up, ifconfig your interface and route add
net default your router. Then go back into suninstall and specify your remote
host as the tapehost. Simple as that.

> For that matter, how does one boot a diskless Sun across subnets ?

You can't unless your router cooperates.

George D M Ross, Department of Computer Science, University of Edinburgh
     Kings Buildings, Mayfield Road, Edinburgh, Scotland, EH9 3JZ
Tel: 031-650 5147   Internet: gdmr@dcs.ed.ac.uk   JANET: gdmr@uk.ac.ed.dcs

----------------------- From: bparent@calvin.UCSD.EDU (Brian Parent)

I don't know if this will help, but recently we had the problem of propogating broadcasts across gateways, and unlike one of your respondants, were successful in using the "IP Helper" address on the cisco (ags+). It didn't work at first, but when we told the workstations in the remote lab to use as a broadcast address, it began working. That lab is using a subnetted class B of 132.239.60.{1-62} and a netmask of, so we next tried a broadcast of, which also worked, and we're using that now. We didn't have any luck when we used the older cisco (ags), but I don't remember if we tried the same things. I can't tell you the exact ways to program the cisco, our network guru does that part. Good luck.


From: "Anthony A. Datri" <datri@concave.convex.com>

>would allow the RARP, TFTP and BootP

There is no bootp involved. The bootparams negotiation has nothing to do with bootp.

>The problem is that broadcasts won't propagate through a gateway.

It can be done if you try hard enough, but it'd be so slow that you wouldn't want to.

>I believe that if you start in.routed

Routed is almost always the wrong answer. Use a static route.


From: brossard@sasun1.epfl.ch (Alain Brossard EPFL-SIC/SII)

> How does one run suninstall (SunOs 4.1) if the tape host is on another subnet ?

I've done this often enough with 4.1.1 and it hasn't been a problem with us. However we didn't need to do any special routing since our Cisco's know how to route the 128.178 addresses. But even if it wasn't the case I wouldn't have had any problems since we always run suninstall when booted diskless in multi-user mode with a default route setup.

> For that matter, how does one boot a diskless Sun across subnets ?

The short and easy answer is you use a third machine to answer the broadcasts made by the clients: rarp requests (/etc/ethers and rarpd -a) bootparams requests (/etc/bootparams and rpc.bootparamd) tftpboot request: sun3's & sun4's: no need, just use the syntax: b le(,xxxx,0) where xxxx are the last 4 digits in hex of the iP number of the boot server, I believe that this syntax also takes care of the bootparam request. sun4c's: old ones (open boot prom rev <= 1.6) you need to setup a /tftpboot on your subnet which will hold the two symbolic links: xxxxxxxx -> boot.sun4c.sunos.4.1.1 xxxxxxxx.sun4c -> boot.sun4c.sunos.4.1.1 Where xxx is the IP address in HEX (don't forget leading 0 if any) of the client. (I don't remember how the tftp server is selected, I believe it picks whoever answered the rarp requests so beware of who answers it!). sun4c's: new ones, you can prevent them from doing any broadcasts at the boot prom level, (see previous message on the subject on my part). However, if you don't modify boot and vmunix, they will both in their turn do broadcasts: rarp and bootparams.

So it is quite feasible to boot across subnets (and we do it all the time), but it requires either a third machine or a recent sparcstation and modified boot and vmunix. (I can provide the diff for those two if needed, the diff are about 5 lines for each).

(I have these patches for anyone who wants them, with Alain's permission - mbl)


Alain Brossard, Ecole Polytechnique Federale de Lausanne, SIC/SII, EL-Ecublens, CH-1015 Lausanne, Suisse, +41 21 693-2211 brossard@sic.epfl.ch


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