dplatt@coherent.uucp (Dave Platt) (01/29/88)
We've been running into some problems with our Kinetics KFPS-3, which is
running the UDP-gateway software released with the CAP distribution from
Columbia. The primary symptom is that TELNET sessions stop working.
We're using NCSA TELNET version 2.1, running on a number of Mac SEs
simultaneously on a single AppleTalk network that's connected to our thin
Ethernet via a single Kinetics KFPS-3. Occasionally, a TELNET session on one
of the SEs will lock up... typed input is not echoed, and a "Send 'are you
there?'" command never responds [yes]. Eventually, TELNET disconnects due to
lack-of-response.
If the user attempts to reconnect to the Unix host, TELNET tries for a minute
or so and then puts up the "Host or gateway not responding" dialog box. If
the user exits from TELNET and re-launches it, TELNET is able to communicate
with the gateway and acquire its IP-address [or, at least, the dialog box
asking the user to enter hir network address never appears]. Further attempts
to connect to the host fail in the same way as before... the host never
responds.
If TELNET loses contact with the outside world in this fashion, another
symptom appears... the "Dumper" RDEF (part of the MacDump package) is unable
to "see" the Unix host's macrestore service, and will not permit the user to
select the host as an authorized disk-dumper. [The TELNET problem was
occurring for several weeks before I installed Dumper, so I don't believe that
Dumper introduced the problem].
The only way out of this situation is to reboot the affected Mac; once it
comes back up, TELNET sessions can be opened once again, and the Dumper RDEV
can once again select the host.
All of the above leads me to think that the gateway code is somehow losing
track of the routing information that would permit the Unix host to send UDP
and/or encapsulated-AppleTalk packets to the Mac. The atalk log in /usr/adm
is entirely unenlightening.
Has anyone seen problems like this, and/or suggest a solution?
--
Dave Platt
UUCP: ...!{ames,sun,uunet}!coherent!dplatt
Internet: coherent!dplatt@ames.arpa, ...@sun.com, ...@uunet.uu.netRavinder.Chandhok@GNOME.CS.CMU.EDU (01/29/88)
Dave, I have seen the problem of TCP getting into a hung state with NCSA telnet, but it generally happens to me during an FTP (the byte count stops incrementing and then the file transfer times out with no error message). Perhaps this is related. The next time it happens to me I will try and use dumper to contact the mac and see if the same problem occurs. However, it just dawned on me that the routing that the Dumper RDEV uses in the AppleTalk routing (which has a lot to do with atalkatab) and Telnet depends on the IP routing, which is almost non-existant. The only thing the "routing" the TELNET requires of the gateway is for the gateway to proxy arp and remember the mapping between IP addresses and AppleTalk ones. It also seems that the next logical thing to try is to NOT reboot the mac, but reboot the KBox, and then start TELNET again and see what happens. Sound resonable ? Rob