Re: Mail loss!

[Richard A Nelson <cowboy@vnet.ibm.com>]

On Tue, 1 Feb 2000, Michael Meskes wrote:

> Last night I did some changes to my /etc/hosts.allow file and accidently
> deleted the newline after 'sendmail: all'. Of course this causes libwrap to
> not like the file anymore. However, there seems to be a bug in there because
> it created some strange log messages (cannot include them now since I write
> from a different machine, but can send them later) containing lot's of non
> letters.

Please, when editing files as important as /etc/hosts.(allow,deny), 
utilize the supplied check routines... in this case: tcpdchk - it
can save you some of these problems...

The start of those messages are likely to be important !

> Anyway, this caused sendmail to not deliver all mail I retrieved through
> fetchmail. But it did accept the mail since fetchmail gladly flushed the
> mailboxes. AFAICT sendmail did not bounce the mail either it just
> disappeared. I'm not sure about that but I did not get a resend either and I
> supposes some of the guys who send me mail would have tried a second time.

Mail doesn't just disappear...  check /var/log/mail.log, there *will* be a
log of what sendmail did with it (even if decided to /dev/null the mail).

If tcpd reported no access to sendmail (as a result of the trailing newline
being deleted), people would get:
  550 5.0.0 Access denied 
on any smtp command beyond the helo/ehlo and you will have something like 
this in /var/log/mail.log:
  Feb  1 15:25:43 badlands sendmail[5303]: e11KPhb05303: tcpwrappers (valhalla.lexington.ibm.com, 9.51.81.10) rejection

This is a *permanent* rejection, and should not be retried by upstream
mailers...  fetchmail would be justified in flushing the messages.

Since it is the connection that is refused, there isn't a bounce message
generated... your buddies will probably never know their mail didn't arrive.

> This IMO is untolerable behaviour (if sendmail really threw it away) and not
> suitable at all for a product called stable. I'm going to switch to postfix
> now (well I planned on doing this earlier so it is not really a result of
> this loss). 

Look, I'm sorry you apparently lost mail, but this is in no way the fault
of the MTA...  You'll likely have exactly the same problem if the MTA of
your choice is built with tcpd support.

> Also I send out a similar mail last night too, but so far did not see it on
> the list. I get the feeling my provider also has some serious problems.

Can't help with that... my access is very sporadic ... now when I get 
Debian running on that S/390, well maybe I'll be happier...

-- 
Rick Nelson
C:\WINDOWS C:\WINDOWS\GO C:\PC\CRAWL