Subject: [netatalk-admins] Inconsistant npblkup results

From: Kent Reuber <[email-masked]>
Date: Thu, 6 May 1999 12:27:07 -0700

My boss reported to me that he was having problem with AppleTalk this
morning, in terms of not being able to see zones. He can see a few printers
and a few file servers, but no where near what he should be able to. When I
use nbplkup on my Linux workstation, I get very inconsistent results. When
I do repeated npblkups:

nbplkup :LaserWriter     <= 12 printers show up
npblkup :LaswerWriter    <=  5 printers show up
npblkup :LaswerWriter    <=  5 printers show up

Similarly, if I look for his machine (even after moving it from an Asante
10/100 card to built-in Ethernet):

nbplkup MacGoodrich    <= 5 services
nbplkup MacGoodrich    <= nothing shows up
nbplkup MacGoodrich    <= nothing shows up
nbplkup MacGoodrich    <= nothing shows up
nbplkup MacGoodrich    <= nothing shows up

>From this kind of behavior, it looks to me as though there is a fair amount
of traffic on the net and devices can't get back under the timeout period.
Is there a way to adjust the timeout in nbplkup to see if this is indeed
the case?

In both cases, I get more results the first time I do a lookup, and less
later. Even more interesting, if I search for LaserWriters for a while,
then search for my boss's computer, his computer will appear the first
time, but then won't appear in subsequent lookups. Why would this be? Does
nbplkup do some sort of caching? In other words, the sequence of commands
looks something like this:

nbplkup MacGoodrich    <= 5 services
nbplkup MacGoodrich    <= nothing shows up
nbplkup MacGoodrich    <= nothing shows up
nbplkup :LaserWriter     <= 12 printers show up
npblkup :LaswerWriter    <=  5 printers show up
npblkup :LaswerWriter    <=  5 printers show up
nbplkup MacGoodrich    <= 5 services
nbplkup MacGoodrich    <= nothing shows up
nbplkup MacGoodrich    <= nothing shows up
nbplkup :LaserWriter     <= 12 printers show up
npblkup :LaswerWriter    <=  5 printers show up
npblkup :LaswerWriter    <=  5 printers show up

Background:

We put in a number of Cisco 2900 switches into our building this summer,
and things have been running very well. I've tried forcing the switch and
his computer to use 100MB full duplex, which wasn't helpful. It also makes
putting a packet sniffer on the net much more difficult.
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Kent Reuber ([email-masked])              Phone (650)725-8092
Customer Assistance                                    Fax (650) 725-0995
Information Technology Systems & Services  215 Panama St., Bldg A (Birch)
Stanford University                               Stanford, CA 94305-4128
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