Re: trying to talk with myself..

[davidn@sdev.usn.blaze.net.au (David Nugent)]

Gyula Matics writes:
> After a power cut (no UPS... ouch)  and crash: 
>  zmailer stopped receiving sending messages to the proper recipients.
> instead the postmaster started to receive messages like this.
~
> <smtp GARFIELD.sch.bme.hu linux-kezdo@GARFIELD.sch.bme.hu 65535>:
> Trying to talk with myself!


Well, now at least I don't feel lonely. :-) I've seen this
too, some weeks back. There was no intermediate crash, but it
just started happening one evening (and only noticed after a
good portion of an entire night's mail got bounced :-().

I haven't see it for quite a while though, and when I did it
was when I was running Zmailer .37 & .38 under Linux 2.0.x
kernels with the then current libc. We have since moved to
FreeBSD on the primary mail server, so I'd be quite interested
to learn if you're also running Linux (perhaps it is OS
specific?). Interestingly enough, the same symptoms of
uppercasing the hostname were also present. To solve it
immediately - only to have it come back eventually - I killed
the running zmailer and restarted. I never did satisfactorily
resolve the cause of the problem, since it was transient and
could not be reproduced at will. I did put both lower and
uppercase versions of the hostname into
$MAILVAR/db/localhosts, and *never* saw it again after that.
At the time, the problem was thought to be DNS related,
although why it would run fine for several months and then
suddenly surface, I don't know.

We exchanged several emails on this mailing list about the
problem, if you'd like to review the list's archive. Most
likely they are more detailed than my admittedly poor memory.

FWIW, while running Linux we also saw the occasional
corruption of headers ("To" and "From" seemed to be primary
targets) that would result in bogus bounces, and eventually
found the only way of solving that was to rm all of the .fc
files, restart the router and let it rebuild them. Since I was
having similar problems with system headers under /usr/include
(like the .fc files, these were rarely updated but read often)
which would be fine one day and corrupted the next, even
though file mtimes would show no change. This occured every
second month or so, and was very frustrating (and no, the
corrupted includes were not from the kernel source tree, but
the ones delivered with the libc package).

Whether these problems are related to what you're seeing, I
don't know, but since moving our network to FreeBSD, we are
not seeing any of these strange little quirks even though the
exact same version of ZMailer is in use (still playing it safe
at .38 :-)). So that this is not misconstrued as a flame
against Linux, the server on which it runs has a fairly heavy
load in terms of mail and general network activity and it used
to perform quite well at most tasks. It is also always
possible that the problem was configuration related (but I
suspect not).


Regards,

David Nugent, Unique Computing Pty Ltd - Melbourne, Australia
Voice +61-3-9791-9547 Data/BBS +61-3-9792-3507 3:632/348@fidonet
davidn@blaze.net.au http://www.blaze.net.au/~davidn