Sender domain must exist

[Dan Schlitt]

I find these all the time in our logs and they are almost certainly from
spammers. I haven't seen any that looked like legit e-mail to one of our
users.

But I have observed the opposite problem in sending mail (actually an
automated send to a mailinglist using majordomo) where some mail bounces
with "host not found" where it is pretty obvious the host should be found.
Doing the query using host finds the DNS records without problem. 

My conjecture is that sendmail isn't waiting long enough for a response to
the DNS query and that might also be the case for your problem.

/dan

-- 

Dan Schlitt                       System Management Arts	
dan at smarts.com                    14 Mamaroneck Avenue
tel: (914)948-6200 x 7210         White Plains, New York 10601


On Mon, 22 Nov 1999, Olaf Ihmig wrote:

> 
> 
> On 22.11.99 10:52:42 Rony Gabriel  wrote:
> >is your domain listed on the dns? if not, then thats the reason.
> >if yes, then you are not properly masquearding the mails to reflect the
> >listed domain name.
> >
> >--
> >rony
> 
> these are not our domains. from time to time there are some domains with
> this errormessage. its not happen on every day, only some. we got mails
> from these and send mail to these domains. its a curios phenomenon.
> 
> olaf.
> >|
> >|
> >| Hi,
> >|
> >| from time to time mails are blocked from our mailserver ( sendmail 8.9.3
> )
> >| with errormessage "Sender domain must exist". Problem is, i am sure,
> sender
> >| domain  exist. Our BIND-Version is 8.1.2.
> >|
> >| Any ideas whats wrong?
> >|
> >| Thanx.
> >|
> >| Olaf Ihmig.
> 
> 
> 
>