Domain name "propagation"

[spober at manhattan.edu]

This weekend, I found that DNS service for one of our servers suddenly
disappeared.  This server holds part of our web presentation, so it's
important that the DNS service to it remain stable.  By trial and error,
I found that DNS for some of our campus servers worked, and for others
(one of the web servers and the pop mail server) the name service
failed, though they were still up and accessible if the numeric IP
address was used. 

The outage lasted about 40 hours, I think.  The server was up and
running and I could ping it and access pages on it using the numeric
address, but my home ISP and several offsite DNS test services could not
find the server when I would put the actual name.  One of the odd things
about this was that one off-site test DNS service *could* find the
correct IP, but the DNS server at Erols, at Princeton, and at several
other sites could not. 

Since the main campus domain name server was up and has the correct DNS
information, and since this situation corrected itself (apparently
spontaneously) sometime late Sunday night or early Sunday morning, it's
making me very curious about domain name propagation on the Internet.  

Can anyone point me to some information that might help explain what
happened?  And are there any steps that I or our campus network techs
can take to help ensure continuous DNS service?  I don't know enough
about the propagation of DNS information to really understand what might
be failing when this happens.  

TIA,
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Stacy Pober, Information Alchemist
Manhattan College Libraries
http://www.manhattan.edu/library/
spober at manhattan.edu