>On Sat, 18 Feb 1995 14:10:08 -0600 Natalie Maynor said:
>>> I'd like to learn how to checkout what is and isn't down so I can
>>> intelligently answer the queries I am getting.
 
When you ask about the "server being down" I believe you are really
asking about end-to-end transmission.  What constitutes E-2-E xmission?
Here's a first pass (in no particular order):
 
.telecom links (usually provisioned by the telephone company incl.
      long distance (IXC) and local operating companies (LEC) (and
      of course overseas circuits)
 
.routers that xmit IP packets (the atomic unit of the Internet)
 
.store-and-forward hosts such as those commonly found on bitnet
      e.g., UGA, PSUVM, SEARN (they need not be listserv hosts)
 
.availability of authoritative hosts for the domain name system
     (these guys translate host names to IP address or to other
     mail exchangers (MX) e.g., NETCOM.COM has 16 MX hosts that
     can exchange i.e., receive mail
 
.mail exchangers (MX) on the Internet
 
.correctly configured RSCS (NJE), MAILER, LISTSERV, SENDMAIL software
 
.correctly configured mail file systems with sufficient disk-space
     for the user
 
.sufficient bandwidth of telecom links
 
.sufficient horsepower (CPU and disk) of sending/intermediate/receiving
     sites
 
Sometimes in trouble shooting, we find that the current configuration is
NOW correct, but in the recent past there was a problem or change and
that residual obsolete info STILL exists at intermediate sites pending a
"timeout" of the cached info.
 
There are plenty of samples of trouble shooting that have been
broadcasted to LSTOWN-L and NODEINFO from such experts as Melvin Klassen
(from whom I've learned alot).
 
Tools such and various inquiries of RSCS, MAILER, SMTP, DNS (DiG or
NSLOOKUP), LISTSERV (DISTRIBUTE MAIL DEBUG=YES wrt REVIEW list) are
used.  Sometimes they require you to be on that network: it might be
impossible to inquiry of an RSCS Q from an Internet host.
 
IMO, understanding "all" of this forms a career path.
 
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