Projects / DynamicRelay


DynamicRelay prevents your customers from sending spam, and authenticates users using POP or IMAP to send email in a pop-before-smtp fashion. You can use it with the wu-imap, dovecot, Courier, and Qpopper IMAP/POP servers, and with Postfix or Sendmail. You set the limit to the number of email messages a user can send per day. This is useful when you have users infected by viruses that send thousands and thousands of spam messages, or who send spam deliberately. You can also control how long users are allowed to send email after their last POP or IMAP authentication. Abuses are logged and emailed to you, and you can put your own static entries in the access file.

Operating Systems

Recent releases

  •  05 Oct 2004 14:51

    Release Notes: This release adds a method to soft-reset sent mails per IP accounting. Also, limits on "peruser_limit" and "whitelist" configuration files now unban the affected IPs, so there's no need to restart DynamicRelay at all.

    •  28 Jul 2004 00:00

      Release Notes: This release adds per-user limits to the number of email messages to send, auto-detection of maillog file rotation, and whitelisting of IP addresses.

      •  12 Jul 2004 23:16

        Release Notes: This release fixes an error in the email notifications about abuses of service. Support for the Qpopper POP server was added.

        •  09 Jul 2004 12:47

          Release Notes: This release adds support for the wu-imapd, dovecot, and courier IMAP/POP servers, support for Postfix and Sendmail, and email notifications for abuse of service (from your customers).

          •  19 Apr 2003 15:23

            Release Notes: A possible relay bypass was fixed. Spammers now get a customizable message warning them about their actions when they try to send more messages than allowed. This release works with pop3d as well as imapd logins. When an IP is considered to be spammer, it gets logged only once per day, and if running in verbose mode, it's shown only once a day until the counters are reset (next day). Some comments have been added to the code. The logic was reordered so that the algorithm is now more consistent.

            Recent comments

            18 Apr 2003 14:11 geeklawyer

            Free speech tool
            Ive often thought what a good tool something like this would be for free speech. Some geek like John Gilmore or RMS (not sure who) has in the past whinged about being blackholed for running an open relay but he refuses to close it saying that people need it in order to be able to make anonymous commentary etc.

            This would seem a good way of getting both: free speech but, with appropriate useage controls, limited risk of abuse by scummy spammers: e.g. anonymous users get 10 emails a day each or 1000 a day for all anonymous users.

            With some development perhaps this project could be made to work like that.


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