How do I permanently delete e-mail messages in the sendmail queue and keep them from coming back?

I have a pretty annoying problem here. I have been testing an application and have created some test e-mails to bogus e-mail addresses (not to mention that my server isn't really set up to send e-mail anyway). Of course, sendmail is not able to send these messages and they have been getting stuck in the sendmail queue. I want to manually delete the messages that have been building up in the queue instead of waiting the 5 days that sendmail usually takes to stop retrying.

I am using Ubuntu 10.04 and /var/spool/mqueue/ is the directory in which every how-to I have read says the e-mails that are queued up are kept. When I delete the files in this directory, sendmail stops trying to process the e-mails until what appears to be a cron script runs and re-populates this directory with the messages I don't want sent. Here are some lines from my syslog:

Jun  2 17:35:19 sajo-laptop sm-mta[9367]: o530SlbK009365: to=, ctladdr= (33/33), delay=00:06:27, xdelay=00:06:22, mailer=esmtp, pri=120418, relay=e.mx.mail.yahoo.com. [67.195.168.230], dsn=4.0.0, stat=Deferred: Connection timed out with e.mx.mail.yahoo.com.
Jun  2 17:35:48 sajo-laptop sm-mta[9149]: o4VHn3cw003597: to=, ctladdr= (33/33), delay=2+06:46:45, xdelay=00:34:12, mailer=esmtp, pri=3540649, relay=mx2.hotmail.com. [65.54.188.94], dsn=4.0.0, stat=Deferred: Connection timed out with mx2.hotmail.com.
Jun  2 17:39:02 sajo-laptop CRON[9510]: (root) CMD (  [ -x /usr/lib/php5/maxlifetime ] && [ -d /var/lib/php5 ] && find /var/lib/php5/ -type f -cmin +$(/usr/lib/php5/maxlifetime) -print0 | xargs -n 200 -r -0 rm)
Jun  2 17:39:43 sajo-laptop sm-mta[9372]: o52LHK4s007585: to=, ctladdr= (33/33), delay=03:22:18, xdelay=00:06:28, mailer=esmtp, pri=1470404, relay=c.mx.mail.yahoo.com. [206.190.54.127], dsn=4.0.0, stat=Deferred: Connection timed out with c.mx.mail.yahoo.com.
Jun  2 17:39:50 sajo-laptop sm-mta[9149]: o51I8ieV004377: to=, ctladdr= (33/33), delay=1+06:31:06, xdelay=00:03:57, mailer=esmtp, pri=6601668, relay=alt4.gmail-smtp-in.l.google.com. [74.125.79.114], dsn=4.0.0, stat=Deferred: Connection timed out with alt4.gmail-smtp-in.l.google.com.
Jun  2 17:40:01 sajo-laptop CRON[9523]: (smmsp) CMD (test -x /etc/init.d/sendmail && /usr/share/sendmail/sendmail cron-msp)

Does anyone know how I can get rid of these messages permanently? As a side note, I'd also like to know if there is a way to set up sendmail to "fake" sending e-mail. Is there?

From serverfault Steven Oxley

• Queued messages are stored in /var/spool/mqueue.

  So try this (I assume you want to get rid of all messages in the queue):

  • Stop sendmail
  • rm -rf /var/spool/mqueue/* (might be called mqueue-client on Ubuntu)
  • Start sendmail
  Massimo : He said he had already done this, but messages re-appeared...

  weeheavy : But without stopping sendmail first, that's the point.

  Steven Oxley : Well, it appears that you may have struck upon the step that I missed.
  From weeheavy

• I don't think this is the work of a cron script, it's more likely to be an application issue, or something related to sendmail itself; anyway, to rule out any cron job doing this, you can just stop crond for a while and see if this keeps happening.

  From Massimo

• I had this same problem and found that there were 2 folders with queued messages. The folder /var/spool/clientmqueue/ had messages that were ending up in /var/spool/mqueue/ if they failed to be delivered. Deleting the files from both folders were necessary to solve the problem.

  rm -f /var/spool/clientmqueue/* rm -f /var/spool/mqueue/*

  From JFister