Very Computer

by **Judg** » Thu, 08 Apr 1999 04:00:00

Hi,
I'm living an installation nightmare at the moment.

We have a network of thin-client netstations with an RH5.1 proxy/bootp/nfs/everything server at it's center.

The netstations were all shipped out with identical MAC addresses, biiigg boo-boo. We've tried manually assigning different IPs to the stations, bypassing part of the requirement for a bootp server, but we're still running into problems when the proxy (squid BTW) is handling web traffic.

My question is, what if I assign the *same* IP address to each netstation ? They already have identical MAC addresses. I'm hoping the stations will start rejecting packets further up the IP stack, oops, wrong sequence number, bye-bye.
Obviously this will flog the network and the CPUs of the stations, but will it work ?

Or is there something magical in Linux I've overlooked that'll haul my ass out of the fire ?

JJ
<who looks rather fetching in flame proof underwear and is hoping to make a fashion statement>

by **Brian McCaule** » Fri, 09 Apr 1999 04:00:00

> The netstations were all shipped out with identical MAC addresses, =
> biiigg boo-boo. We've tried manually assigning different IPs to the =
> stations, bypassing part of the requirement for a bootp server, but =
> we're still running into problems when the proxy (squid BTW) is handling =
> web traffic.

> My question is, what if I assign the *same* IP address to each =
> netstation ?

No way. If you can't change then so that each has a unique MAC
address then you'll have to put each one on a separate port of a
router. That's a _router_ not just a bridge/switch/hub.

Quote:> They already have identical MAC addresses. I'm hoping the =
> stations will start rejecting packets further up the IP stack, oops, =
> wrong sequence number, bye-bye.

No they'll keep resetting each others' connections.

Quote:> Or is there something magical in Linux I've overlooked that'll haul my =
> ass out of the fire ?

If these thin clients are running Linux perhaps "ifconfig hw".

Failing that an old "junk box" 486 with Linux and lots of ethernet
cards is a cheap router.

Quote:> <!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN">
> <HTML>

Please, no!

--

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###LL LL\\ (Brian McCauley) |

by **Ron Watkin** » Fri, 09 Apr 1999 04:00:00

I'd be on the phone to your vendor bigtime. You CANNOT have identical MAC
addresses on the same network without a great heap of jiggery and foolery.
They screwed up badly; you'll need to get them to bail you out of the problem.

Chances are, if they all have identical MAC addresses, there's a method of
changing them.

<<RON>>

by **Stuart R. Full** » Sat, 10 Apr 1999 04:00:00

: This is a multi-part message in MIME format.
:
: ------=_NextPart_000_017B_01BE8132.B41B79C0
: Content-Type: text/plain;
: charset="iso-8859-1"
: Content-Transfer-Encoding: quoted-printable
:
: Hi,
: I'm living an installation nightmare at the moment.
:
: We have a network of thin-client netstations with an RH5.1 =
: proxy/bootp/nfs/everything server at it's center.
:
: The netstations were all shipped out with identical MAC addresses, =
: biiigg boo-boo. We've tried manually assigning different IPs to the =
: stations, bypassing part of the requirement for a bootp server, but =
: we're still running into problems when the proxy (squid BTW) is handling =
: web traffic.
:
: My question is, what if I assign the *same* IP address to each =
: netstation ? They already have identical MAC addresses. I'm hoping the =
: stations will start rejecting packets further up the IP stack, oops, =
: wrong sequence number, bye-bye.
: Obviously this will flog the network and the CPUs of the stations, but =
: will it work ?

The bottom line is that 2 machines having the same MAC address violates the
way that Ethernet works. Until each machine has a unique MAC address, you can
pretty much forget about getting it to work. You might be able to get some
hack going (not very likely), but even if you did, it'll be a support
nightmare.

I'd like to know how it is that each machine has the same MAC address? I
thought that they were supposed to ALL be unique?

Stu

by **Sven Hol** » Sun, 11 Apr 1999 04:00:00

Quote:> I'd like to know how it is that each machine has the same MAC address? I
> thought that they were supposed to ALL be unique?

Hmmm, i think it is possible because just al little part of the MAC is
the real Address because the other part shows the producer of the card.

I also knew about cards where you can manipulate the MAC (interesting in
real big Networks with cards from the same producer)

c ya

xylus

Very Computer

Duplicate IPs PLUS duplicate MAC addresses, has this been done ?

Duplicate IPs PLUS duplicate MAC addresses, has this been done ?

Duplicate IPs PLUS duplicate MAC addresses, has this been done ?

Duplicate IPs PLUS duplicate MAC addresses, has this been done ?

Duplicate IPs PLUS duplicate MAC addresses, has this been done ?

Duplicate IPs PLUS duplicate MAC addresses, has this been done ?