NIS Timeouts? or Something Else?

2007-12-25 8:26:00

I wrote:

>Our local network includes both dial-in terminal servers and

>a local "terminal" network for RS-232-connected terminals, from

>which dial-in and terminal-net users can connect to hosts on

>the local ethernet.

>

>Recently, we have seen lengthy delays in connecting to TCP/IP

>hosts (Suns and RS/6000's) from both the dial-ins and terminal

>nets, with connections (via telnet) taking 3-4 minutes to complete.

>All the TCP/IP hosts which are affected are in a single NIS domain.

>We run NIS-with-DNS, as presribed by Sun.

>

>Our networking folks insist this is an NIS timeout problem--

>specifically, that reverse name lookups (i.e., the TCP/IP host

>attempting to lookup the name of the terminal server trying

>to connect via telnet from its IP address) are failing. They

>tell us this is our problem (with NIS) instead of any general

>network problem. The terminal servers are *not* included in

>our NIS maps, so name resolution has to occur via DNS.

>

>Interestingly, once one such delayed connection has finally been

>made, subsequent ones connect instantly, including subsequent

>connections from the same terminal server to *different* hosts.

>This makes me wonder if the problem might be a router problem,

>rather than an NIS one, since the terminal servers have no

>trouble connecting on subsequent tries.

>

>One further reference point: this problem seems to have begun

>at more or less the same time as I upgraded my master NIS server

>from SunOS 4.1.2 to 4.1.3, restoring /var/yp from a dump tape.

>

Thanks to:

per@erix.ericsson.se (Per Hedeland)

Mike Minnich <minnich@wind.es.dupont.com>

stern@sunne.East.Sun.COM (Hal Stern - NE Area Systems Engineer)

jba@ruc.dk (Jan Bruun Andersen)

The short summary of a long story is that the NIS slave server to

which the clients subject to the delays had bound was not properly

doing DNS lookups for an unknown reason. I re-bound the clients

to another slave server and the problem went away. I then re-

made the slave server.

As an aside, a bit of information I picked up in pursuing this

is that while Sun's NIS-with-DNS does NIS lookups first, then

falls through to DNS, IBM's AIX (I have some RS/6000's functioning

as slave servers) looks to DNS *first* then goes to NIS.


--
Tim Evans | E.I. du Pont de Nemours & Co.
tkevans@eplrx7.es.dupont.com | Experimental Station
(302) 695-9353/7395 | P.O. Box 80357
EVANSTK AT A1 AT ESVAX | Wilmington, Delaware 19880-0357

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