Spam is a big problem these days. Spammers use advanced bots that can post thousand of spam messages on your forum, your blog, or any other type of site that allows the user to post messages or comments. The bots are becoming more and more advanced.
A few years ago it was easy to stop this type of spam using methods like CAPTCHA but now the bots have sophisticated ocr algorithms that can easily detect the obfuscated characters in an image so that's not a protection anymore.
If you run a forum with phpbb you will have to install a few mods to protect it against spammers. If you don't do anything you will get hundreds or thousands of spam messages a day, you'll want to bang your head on to the wall trying to keep up and delete the messages and your forum users will most probably leave your forum before you'll manage to get rid of all that spam.
DomainKeys Identified Mail (DKIM) is a method for validating the identity associated with a message using using public-key cryptography and key server technology. DKIM is an enhanced version of Yahoo's Domain Keys and Cisco's Identified Internet Mail methods. As of February 2007 an IETF draft was accepted as "Proposed standard", it may take some more time till this will be a standard but the current version is stable ( according to dkim.org ).
Implementations of DKIM in email servers is not available as much as DomainKeys.
For qmail there is a patch that uses libdomainkeys to implement a replacement for qmail-queue that will verify and sign messages but this only works for DomainKeys not DKIM. I have developed a solution for qmail to be able to verify and sign messages with DKIM. Continue reading
I tried to set up qmail with tls and smtp auth on freebsd. I have configured my server with SMTP-AUTH so that I can use it to relay messages for me and other authenticated users. I would like qmail to sign the messages that the authenticated users send through my server.
I compiled qmail-tls from ports, checked the smtp-auth and qmailqueue options, then I compiled qmail-dk and selected the SMTP-AUTH patch. I set up my private and public keys, I set up bin/qmail-dk for qmailqueue as described on this page : http://jeremy.kister.net/howto/dk.htm but still not results. It just does not want to add the DomainKeys signature but instead it tries to verify the messages. Continue reading