On Sun, 2009-12-06 at 11:13 -0800, Andrew Danneffel wrote:
> Thanks for your input, all.
>
> I am not using any catch alls. However, I did activate a catch all for
> about 20 minutes as suggested to see what was trying to be sent. I received
> 3000+ spam messages during this time - and given the subject lines they were
> all obviously spam. They were being sent from hundreds of different IPs so
> it was difficult to find one or two main offenders.
You need to execute 'make'
then restart sendmail
cd /etc/mail
make
/etc/init.d/sendmail restart
> I did not have the blacklists (i.e. spamcop) activated until yesterday. Now
> that they are active the server is doing a better job identifying and
> stopping spam but I am still receiving thousands of the "No such user here"
> errors in the maillog.
>
> Gerald, I have looked in the sendmail.mc file and sure enough, there is a
> line:
>
> FEATURE(`accept_unresolvable_domains')dnl
>
> I have noticed that most of the spam IPs are unresolvable to a hostname so
> disabling this setting may help a great deal. I commented out this line in
> sendmail.mc and then adjusted some settings in the GUI to have the .mc data
> written to the sendmail.cf file. My edit in the .mc file did not seem to be
> overwritten by the GUI. Is what I did sufficient to make this adjustment
> active for sendmail?
>
> Andrew
>
> ----- Original Message -----
> From: "Gerald Waugh" <gwaugh (at mark) raqware.com>
> To: <coba-e (at mark) bluequartz.org>
> Sent: Saturday, December 05, 2009 5:04 PM
> Subject: [coba-e:16181] Re: No such user here
>
>
> >
> > On Sat, 2009-12-05 at 14:02 -0800, Andrew Danneffel wrote:
> >> Hi there,
> >>
> >> My Blue Quartz server is constantly being hammered with email to users
> >> that do not exist on the server (I believe they are referred to NDRs).
> >> The maillog lists thousands and thousands of these "No such user here"
> >> errors each day. Strangely the vast majority of them are to two
> >> domains, each which start with "a". I don't believe the server is
> >> automatically sending out responses to these senders as this has been
> >> happening for some time and the server is not blacklisted from what I
> >> can see. I understand that these messages are from spammers and that
> >> the sender email addresses are spoofed.
> >>
> >> I am wondering what (if anything) can be done to prevent the server
> >> from processing and logging all of these useless messages. I suspect
> >> all of these mail requests are generating significant data transfer.
> >> Is it simply a fact of life or can some component of the mail system
> >> be optimized to stop it?
> >>
> >
> > Are you using any catchall email accounts?
> > If so stop using them!
> >
> > Is you sendmail.mc / cf configured to accept unresolvable domains?
> > If so reconfigure
> > Also check if Sendmail configured for DNS-Based Blacklisting
> >
> > Gerald
> >
>