Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!ucbvax!cayman.com!brad From: brad@cayman.com Newsgroups: comp.protocols.appletalk Subject: Re: Telnet/MacTCP/Appletalk problem Message-ID: <9002071348.AA19630@cuba.Cayman.COM> Date: 7 Feb 90 13:48:26 GMT References: Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 54 >> Subject: Re: Telnet/MacTCP/Appletalk problem >> Message-Id: >> 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