Projects / vthrottle


vthrottle is an implementation of an SMTP throttling engine for Sendmail servers, based upon M. Williamson's mechanisms, as described in his 2003 Usenix Security paper. It allows the administrator to control how much email users and hosts may send, hindering the rapid spread of viruses, worms, and spam. Exceptions can be made using a whitelist mechanism, which can be generated manually or with the included tool "vmeasure". vthrottle tells the misbehaving client to hold on to the deferred mail and resend it at a later time.

Operating Systems

Recent releases

  •  15 Nov 2006 06:01

    Release Notes: Logging and handling of mail was improved. A cleanup function was added. Changes were made to logging. Reliability was improved.

    •  04 Jun 2004 20:28

      Release Notes: An issue with "throttled XXXX times" reporting has been fixed.

      •  03 Jun 2004 04:14

        Release Notes: Major bugfixes were made, improving stability and correctness. A couple of logic errors were corrected and some code was refactored. Upgrading is recommended.

        •  02 Jun 2004 15:41

          Release Notes: A few bugs were fixed. setreply() is now respected. The logging and documentation were improved. The whitelist syntax was adjusted a bit.

          •  04 Feb 2004 06:17

            Release Notes: This release is focused on minor bits of code cleanup in error checking and mutex locking.

            Recent comments

            02 Jun 2004 08:24 jnazario

            Re: vthrottle EOL

            > sendmail 8.13 is currently in beta and

            > includes a mechanism to vthrottle to

            > control mail rates.

            that should read "a mechanism similar to vthrottle ..."

            really, my grammar isn't THAT bad :)

            02 Jun 2004 08:23 jnazario

            vthrottle EOL
            sendmail 8.13 is currently in beta and includes a mechanism to vthrottle to control mail rates. because this is built-in to future versions of sendmail, vthrottle is marked for EOL when 8.13 comes out. this will give people a portable, supported mechanism to control their mail with the same goals as vthrottle. vthrottle will probably never be ported to other systems like Linux or solaris, therefore. however, until 8.13 is released i'll keep playing with it.

            i'm excited to see sendmail doing this.

            postfix users may want to look at the anvil tool in new postfix versions, it does similar mail control.

            thanks for your interest in vthrottle.


            Project Spotlight


            A Fluent OpenStack client API for Java.


            Project Spotlight

            TurnKey TWiki Appliance

            A TWiki appliance that is easy to use and lightweight.