RE: Strange bind/sendmail issue

[Erik Dörnbach <doernbach@elge.de>]

Sorry for the long lines, I know about them...
I'll move the lists stuff over to a different MUA some time. :)

> Take a look at /etc/resolv.conf and look at the search path.  
> For a mail 
> server, you may want to completely remove the search line.

Exactly my first thought, but the search directive has only the internal NS zone defined, "customer.lan" and not "customer.com".

> 
> On Wed, 27 Sep 2006, Erik Dörnbach wrote:
> 
> > Hello list,
> >
> > at one customer's site I encountered a really strange 
> issue, regarding sendmails handling of emails with 
> non-existing domains as recipient... running bind9 and sendmail.
> >
> > In detail, for what ever reason a mail with non-existing 
> domain may enter the sendmail queue, it appears with the 
> customer's own domain trailed to the non-existing one, making 
> it appear as if it was a subdomain, likewise it's treated as one.
> >
> > For example:
> >
> > - Customer has domain "customer.com", the server in 
> question is the mx for that domain
> > - Mail enters the queue with recipient address 
> "user@doesnotexist.net"
> > - Mail is listed in queue/log as 
> "user@doesnotexist.net.customer.com"
> >
> > What is going on? I don't have this phenomen on any other 
> of my machines with quite the same configuration running. 
> It's not much of a problem, but I would like to understand 
> what is going on there, either on the resolver or sendmail. 
> And have a cleaner mail queue of course! ;)
> >
> > I can give more information about sendmail config, bind 
> config, ns queries and so on as needed on request.
> >
> > The only thing that caught my attention, the authoritive NS 
> for "customer.com" (not under my control) does some special 
> magic to make all queries to non-existing hosts under 
> "customer.com" point to itself. I'm not sure what that is 
> for, but that's why sendmail tries to deliever those emails 
> to that NS.
> >
> > But then this can't be the source of the problem... I think.
> >
> >
> > THX and with best regards,
> >
> > Erik
> >
> >
>