[CentOS] sendmail security-with example

Les Mikesell lesmikesell at gmail.com
Thu Sep 21 12:42:41 UTC 2006

On Thu, 2006-09-21 at 02:18, Feizhou wrote:
> >> i have never opened telnet ok , my xinetd service is
> >> off so there is no telnet service , i m doing telnet
> >> to outside to 25 port on my mail server and there is
> >> proper smtp authentication  enabled on server , the
> >> problem is anyuser (non-existing) with my domain can
> >> send mail to my real domain users.
> >> below is example........
> >>   
> > 
> > Check this and do accordingly ...
> > 
> > http://www.sendmail.org/faq/section3.html#3.27
> > http://www.sendmail.org/tips/relaying.html
> > 
> > hope this help!
> > 
> It does not. He does not have a relay problem. He wants to reject mails 
> that have sender addresses claiming to be from his domain and not only 
> that, they are also forged (non-existent).

Custom tests are fairly easy if you add MimeDefang to your
sendmail setup.  An example was just posted to their mail
list that would reject hosts claiming to be in your
domain but not in your IP ranges.  This would be used
along with SMTP AUTH if you do want to allow your own
users to roam and send from remote locations.

  Les Mikesell
   lesmikesell at gmail.com

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