cetron@UTAH-CS.ARPA (Edward J Cetron) (09/16/86)
After hacking with the Tek tcp/ip package to add keep-alive (or probe-alive as the case may be) support, I found the following behaviour from two Ultrix sites: line sits idle for x length of time (so snd.nxt = snd.una = Ultrix rcv.nxt...) Tek tcp/ip sends a packet designed to be unacceptable in order to force a response (as documented in the mil-std and rfc for tcp). This packet has seg.seq = snd.nxt-1 and seg.ack = rcv.nxt-1 which is obviously unacceptable and should force and ack with the proper counters. The Ultrix site receives the packet, and promptly drops it off of the face of the earth (though apparently reading the code it does use it to update the window...) Am I missing something or is this indeed non-compliant? All of the 4.2bsd and 4.3 bsd sites handle this fine... I know what is different between the 4.3bsd and the Ultrix code but before I fix it myself, I want to be sure I haven't overlooked something and/or that other Ultrix sites have noticed this same problem.... thanx ed cetron%utah-cbd@utah-cs.arpa
louie@TRANTOR.UMD.EDU (Louis A. Mamakos) (09/17/86)
I've noticed other TCP problems with Ultrix 1.2's TCP. After we installed ULTRIX on a MicroVAX system, we don't seem to be able to send mail to our Sperry 1100 system anymore. The connection just hangs after a bit. This concerned me greatly, being one of the authors of the TCP/IP software on the Sperry host. None of our other systems had any problems, (2.9BSD UNIX, 4.2 BSD UNIX, Wollongong VMS, FUZZBALL, *Ultrix 1.1*). Examination of trace data on the Sperry indicates that it's just waiting for more data on the SMTP connection after sending a window update. (Flame on) Our solution? Very simple. Trash Ultrix and run 4.3 BSD. Not only has DEC managed not to fix broken code, but they've even broken working code! I'll just bet DECNET works though. (Flame off) Louis A. Mamakos WA3YMH Internet: louie@TRANTOR.UMD.EDU University of Maryland, Computer Science Center - Systems Programming
dardy@NRL-ACOUSTICS.ARPA ("Henry Dardy") (09/21/86)
You are right: Decnet works perfectly! ***Cough, ghasp, wheeze***. Sorry, but your (flame on) hadn't cooled yet! Hank ------