[comp.sys.mac] appletalk address

sr6371@sdcc15.UUCP (yip) (12/19/87)

Does anyone know how to set the appletalk address for a mac to a specific
number?

thanks,

David Yip
sr6371@sdcc15.ucsd.edu
stuff@crash.cts.com

phil@apple.UUCP (Phil Ronzone) (12/21/87)

In article <404@sdcc15.UUCP> sr6371@sdcc15.UUCP (yip) writes:
>Does anyone know how to set the appletalk address for a mac to a specific
>number?
>
>thanks,
>
>David Yip

A1 - You can't have the node address stay at the same number,
     not without patching code.
A2 - And you shouldn't, because dynamic node addressing is assumed
     with AppleTalk.
Q1 - Why would you want to? (Curiosity only compels ...)

sr6371@sdcc15.UUCP (yip) (12/22/87)

	I need to do this because one of my ethernet programs won't use the
address I give it, but instead builds one from my appletalk address.  This
has a bad side effect that if someone else has that internet address it
causes problems.

	I thought the numbers were randomly assigned, but everytime I run
this program, or any other program that shows what the numbers are, the
appletalk address is always the same.   

rmh@apple.UUCP (Rick Holzgrafe) (12/22/87)

(Last time I opened my big mouth, I rammed my foot down it -- twice.
Nothing daunted, here I am to try again...  :-)

In article <404@sdcc15.UUCP> sr6371@sdcc15.UUCP (yip) writes:
>Does anyone know how to set the appletalk address for a mac to a specific
>number?

Alas, you can't.  There are no permanent addresses in AppleTalk; addresses
are assigned dynamically whenever the Mac comes on-line on the net.  You
use NBP (Name Binding Protocol) to assign an arbitrary (and presumably
unique) name-and-type pair to a node-and-socket, and other folks wishing
to talk to you can use the well-known name-and-type to learn the address.

Addresses frequently remain "relatively constant": that is, the address the
Mac chooses is likely not to change if your net is stable.  This can create
an illusion of permanence.  There is a way to take advantage of it: use
NBPLookup the first time to learn the address of the destination, then
remember both the name and the address for future use.  There is an NBP
operation called NBPConfirm (IM II-301) which allows you to check that
the address is still good, with greater efficiency than a look-up.  If it's
still good, fine; if not, do the look-up again.

I hope a flame war doesn't start over networking strategies :-).  The dynamic
nature of AppleTalk addresses is to allow the "plug-and-play" feature:
no configuration needed, just plug that little cable in the back of your
Mac and boot it, and you're on the net.  The Mac does the rest.

For more info, see "Inside AppleTalk".  I don't know where you can get
it (I got mine from my Area Associate) but you might try your local
technical bookstore, or APDA.

Hope this helps.

==========================================================================
Rick Holzgrafe			 | {sun,voder,nsc,mtxinu,dual}!apple!rmh
Communications Software Engineer | AppleLink HOLZGRAFE1 (I don't look often)
Apple Computer, Inc.		 | "All opinions expressed are mine, and do
20525 Mariani Ave. MS: 27-Y	 | not necessarily represent those of my
Cupertino, CA 95014		 | employer, Apple Computer Inc."