From: glen@Cayman.COM (Glen B. Glater)
Newsgroups: comp.sys.mac.comm
Subject: Re: Gatorbox and IP addresses
Date: 14 Dec 92 23:30:23 GMT
	<1992Dec13.051351.8080@wolves.Durham.NC.US>
Distribution: usa
Organization: Cayman Systems Inc., Cambridge, MA
In-reply-to: ggw@wolves.Durham.NC.US's message of 13 Dec 92 05:13:51 GMT

In article <1992Dec13.051351.8080@wolves.Durham.NC.US> ggw@wolves.Durham.NC.US (Gregory G. Woodbury) writes:

  >>It was suggested that one could use the address that the GatorBox is
  >>reserving for the Mac (so it can do AT-IP encapsulation if connecting
  >>via AppleTalk/LocalTalk) also as the IP address for the direct Ethernet
  >>interface.

  >NOT!

NOT NOT!!  ;-)

  >The GatorBox will be doing proxy arp on the Ethernet for that IP
  >address, and routing the IP packets to it via the LocalTalk wire.
  >
  >When the MacTCP protocol stack tries to open, it will try to verify the
  >IP address it was given on the Ethernet (to make sure that it isn't
  >using an IP address already in use by someone.)   This ARP request will
  >"fail" in that the GatorBox, seeing a request for an IP address that it
  >is routing to, will respond and the MacTCP stack will fail to complete
  >its setup.

The GatorBox can be configured to assign Macs on the Ethernet an
address.  That address can (possibly) be the same address that the Mac 
would get on LocalTalk.

It is important to remember that you have to change the icon in MacTCP 
when you change from LocalTalk to Ethernet.  If you want the GatorBox
to assign an address to the Mac on Ethernet, you need to use the EtherTalk 
icon.  If you want to assign the Mac a static address on the Ethernet, you
should use the Ethernet icon.

  >This was the cause for my recent question about using Ether and
  >LocalTalk at the same time last week or so.   I was getting errors from
  >Fetch and NCSA Telnet (2.5) complaining about not having MacTCP
  >installed, andor "No Dynamic Addressing" being available.  (Quite the
  >misleading error message there.)
  >
  >Being the LAN administrator, I assigned myself an unused address in the
  >subnet, and BINGO!   Works like a charm.  Now, I either have to modify
  >the address ranges that the GatorBox thinks are its redirecting
  >addresses, or fully register the Mac under a new IP address in the host
  >tables out there on the rest of the Wide World of Internet.

If you have a Mac on the Ethernet network, this is by far (IMHO) the best
solution.  Why make the GatorBox (or any other DDP-IP Gateway for that 
matter) encapsulate and de-encapsulate the packets in AppleTalk when
the Mac can speak IP right out on the net?

  >Given the nature of the problem, I don't think it is likely or
  >reasonable to complain to Cayman about the GB not "doing what I mean" :-)

Thanks!!

I will mention, however, that anyone having any problems or questions
about the GatorBox or any Cayman product should feel free to send
email to support@cayman.com and your questions will be promptly answered.

Glen
--

	*************************************************************
	Glen B. Glater				Phone: (617) 494-1999         
	Technical Support Engineer		Fax:   (617) 494-5167         
	Cayman Systems Inc.			Internet: glen@cayman.com     
	26 Landsdowne Street			AppleLink:  CAYMAN.TECH	      
	Cambridge, MA   02139            SneakerNet:  3rd cube on the left