🚀 go-pugleaf

>> Subject: Re:  Telnet/MacTCP/Appletalk problem
>> Message-Id: <Feb.6.16.54.00.1990.24767@khnphwzhn.njin.net>
>> References: <9002061545.AA01125@icarus.cns.syr.EDU>
>> Sender: info-appletalk-request@andrew.cmu.edu
>> To: info-appletalk@andrew.cmu.edu
>> 
>> I use NCSA 2.3 Telnet with MacTCP, and when going through a KFPS4
>> running K* 8.0, the same problem occurs with static addresses. I always
>> used a static address (with the rest being dynamic) when I had a
>> KFPS-2 running KIP.  I didn't have this problem with MacTCP talking to
>> KIP. It seems more likely to be a K* 8.0 problem than one with MacTCP.
>> Does anyone see their telnet sessions hang when using MacTCP with
>> static IP addresses when going through anything other than K*?

I will offer a guess as to why this is happening (as the same problem occurs
with a GatorBox).

-- my humble opinion as to the cause --

Dynamically assigned IP addresses establish the appletalk address of
the Macintosh host (the mac running MacTCP) at the time the address is
assigned. This assignment is done via a sequence of ATP transactions.
The address of the mac host is taken from the source of the ATP assign
transaction. (so, as long as the host can find the gateway, it can be
located anywhere on the appletalk internet)

Once assigned, the validity of the address is "maintained" via NBP Confirm
requests, which are sent directly to the appletalk address of the mac host.

Statically assigned IP addresses establish the appletalk address of the
Macintosh host by using "NBP ARP". This is a broadcast protocol. If the
mac host is not in the same localtalk zone as the gateway, the address can
not be verified and will time out. (this takes about 2.5 - 3 minutes as per
the holy grail of the Croft KIP gateway code ;-)

The point is that statically assigned addresses are not "maintained" at
constant intervals like dynamically assigned addresses.

-- editorial --

There are some easy ways to fix this - perhaps the behavioralism of the
ip arp cache can be changed to notice appletalk based resolved addresses
and before they time out, "verify them" with an arp resolve to "refresh"
the entry.

There is some work going on in the Macintosh IETF sub-sub-workgroup (it has
some name like that - as a member, I am obligate to forget and incorrectly
propagate the name ;-) to standardize the "Macintosh IP encapsulated in DDP"
work that exists (KIP, KStar, GatorBox, Dartmouth gateway, Ungerman Bass, etc)
Both Cayman and Kinetics have put out "white papers" on the "here and now"
and the "why is should be" respectively. These will be available via anonymous
ftp (if I ever get my butt in gear)

-brad