OT: how to block emails sent to too many recipients

Denis Beauchemin Denis.Beauchemin at USherbrooke.ca
Mon Dec 20 14:42:30 GMT 2010

> -----Message d'origine-----
> De : mailscanner-bounces at lists.mailscanner.info [mailto:mailscanner-
> bounces at lists.mailscanner.info] De la part de Steve Campbell
> Envoyé : 20 décembre 2010 09:24
> À : MailScanner discussion
> Objet : Re: OT: how to block emails sent to too many recipients
> Another thought:
> If you can find a common IP from your apache logs, firewall that off. If the
> sending IP is not one of those random IPs, add it to your access file.
> Sometimes, you may need to add a few IPs if they're slightly random. If
> they're truly random and spoofed, the access file won't help.
> Steve Campbell

Unfortunately it comes from too many different IPs.

The server is used to send big batches of emails (people with Outlook mailing lists, webmails, etc). That's why it is so difficult to take drastic measures like confMAX_RCPTS_PER_MESSAGE which applies to all users.

All users of our webmail are authenticated. Don't know if some accounts were broken into or if there is some cookie hijacking going on...  I think we patched Horde last week (not my team's responsibility). We're asking the guys that maintain Horde to try to block them at the source: if from is not from our domain and there are more than 25 recipients then reject the message. Hope they can pull it off!

Thanks for your help!


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