andrew@megadata.mega.oz (Andrew McRae) (08/08/90)
I have the following configuration:
192.1.2
----+---------------------------+------- Ethernet #1
||| |||
+-------+ +-------+
| | | |
| A | | B |
| | | |
+-------+ +-------+
||| |||
----+---------------------------+------- Ethernet #2
192.1.3
Where A is a Sun Sparcstation, and B is a custom box.
Each machine has two network interfaces, onto two
nets (physically and IP-network-number separate). Machine
B wishes to boot from machine A, and may not know its
IP address. So it uses broadcasts RARP on first one
net, and then the other if the first doesn't reply.
The hosts file is:
192.1.2.1 a1 # Machine A network 1
192.1.3.1 a2 # Machine A network 2
192.1.2.2 b1 # Machine B network 1
192.1.3.2 b2 # Machine B network 2
and the ethers file is:
xx:xx:xx:00:00:01 a1 # a2 as well
xx:xx:xx:00:00:02 b1
The question is: Does B have to have two separate Ethernet
addresses so that A can distinguish the RARP broadcasts
on each net? If B has only ONE ethernet address, and it
broadcasts on net #1, will the RARP server (rarpd on Sun) be
smart enough to know that it shouldn't reply with an IP
address that doesn't match the network the broadcast came in on?
Or doesn't it care?
If B has two ethernet addresses, then the problem is solved,
but I know there is some confusion about whether it is `the
right thing' to have the same ethernet address on all
network interfaces, or whether it is correct to have
different ethernet addresses on each interface. Some
boxes (I think Suns fall into this category) don't have
a separate ethernet address PROM for each interface, but
only have a master PROM.
Thanks,
Andrew McRae inet: andrew@megadata.mega.oz.au
Megadata Pty Ltd, uucp: ..!uunet!megadata.mega.oz.au!andrew
North Ryde 2113 Phone: +61 2 805 0899
NSW AUSTRALIA Fax: +61 2 887 4847