[Wylug-help] Mail server problem

[Darran Rimron]

Anne Wilson wrote:

> That's the crux of the matter.  I have checked every log file I can find,
> without finding any reference to the problem.  I can't believe that it
> is not
> being logged, but I can't find it.

Usually, by default, xinetd won't log anything (in some cases
distributions change the config and it logs some, but _very_ little -
eg, username of a unsucsessful login or similar, but there's always more
;)  ), because it leaves all that up to the called.  When you remember
things like both apache and samba can be shoe-horned into
xinetd-launched-configurations, should the need arise, you can
understand why xinetd leaves the logging to "someone else", both those
(as a tiny fraction of examples) could (and do) log far more (relevent)
information than [x]inetd ever could.

A tip: (may be REALLY obvious, but still worth remembering)

When I was at uni they taught us to debug by writing what we are trying
to acheve at the top of a piece of paper, and the "thing" that achieved
it at the bottom. In your case that would look (for a subset of your
solution) like this

Check mail on a different PC
 |
 |
 |
 |
 |
 V
pop3

And on each line write a stage/layer that has to be gone through. For
example, immediatly above pop3, in this case, is xinetd, above that the
firewall, and that, the network - and so on and so forth.

Debug from the bottom up (not all layers will have a debug facility
without hardcore effort [tcpdump, etc]), and keep on trying until you
get some sort of output that is useful - centralised debugging output
(in a *nix domain, this can often be read as "syslog") helps. Especially
if you take the time to learn about syslogs various logging targets
(0-7, daemon, auth, user, etc).

One last "point" - most production environments (consider any
distribution, out of the box, to be setup for "production" environment
in this respect) have logging tuned to a minimum or, as is often the
case for web-orientated-stuff, at some sort of trade off re:
performance/data-logged.  By poking the right places there's almost
always lots more juicy gossip for you to find. If you're not seeing
anything in the log files when errors occour, the first thing to check
is "how do I crank my logging up so it notices EVERYTHING".  Most apps
will have a debug mode, somewhere.... (how did you think the developers
coped?)

Now, in your case, pop3d isn't going to do much without xinetd, so
that's the place to start. man xinetd (on my debian box) gives some
pretty helpful options on debugging. For the "newbie" -filelog may be
easier than -syslog (one less beast to tame and all that....) also
remember that items such as xinetd fork and background themselves for
connections so disabling those features help ( see -dontfork & -stayalive)

Good luck!

D