Tag Archives: Spam

Mailbait Threats

Back in October of 2012 I devised a way of blocking abuse of my mailing list server by detecting mailbait abusers (mailbait.info offers a ‘service’ to fill your, or someone else, mailbox with unwanted mailing list subscriptions). In June of 2013 I refined the technique.

Basically I detected if someone was visiting the mailing list subscribe page from mailbait.info and sent them to a special page that also annoyed them by popping up hundreds of javascript alerts about not spamming people.

Regardless of the popups, people still try to use mailbait to involuntarily subscribe people to my lists (well, try at least, my lists require a closed loop confirmation system).

Today I received the following threat from a mailbait.info user ..

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I’m inclined to ignore the ‘warning’ … but I find it somewhat satisfying that my approach has annoyed someone sufficiently.

As an added measure, I’ve updated my system security mechanism to block any IP that attempts to use the mailbait service more than once.

Tech Tip: Don’t use qmail as a mail server

A while ago I added a new anti-spam technique to my mail server setup called “No Listing”.

No listing basically means putting a high priority MX record in the DNS that always rejects mail server connections..

It seems, however, that the qmail mail server can’t cope with that.  It’s not RFC compliant.

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Adding Envelope Sender in sendmail

Fair warning: This post is pretty darn technical and is of little interest to people who don’t muck around with Linux and/or mail servers.

Recently I had a problem with someone on a midrange.com mailing list where they sent obvious spam.

The problem was, they were a subscriber to the list and had posted before … so the normal counter measures for that didn’t work (the first post for all subscribers are held until approved, to prevent people from subscribing, posting spam, and unsubscribing).

The puzzling thing about this was … the ‘from address’ on the message was not in the subscriber list.

Turns out that Mailman will accept message based on the FROM address of the message or the SENDER address (also known as the envelope-from).  The sender addressed is set by the sending mail server and is not normally in the body of the message.

After a bit of digging around, I figured out a way to add this information to the message headers so I can more easily diagnose the problem in the future.

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DNS: Sends No Mail

I really wish there was a way to indicate, in DNS, that a domain never sends mail.

That way, if a mail server recieves mail claiming to be from that domain, it can be discarded out of hand.

I’ve got a bunch of domains that JUST do web serving … they never send mail.  If the web server that they are hosted on does send mail, it’s sent from via the midrange.com mail server (and is identified as such).

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Report as SPAM

It’s nice that many of the major mail providers give you the ability to report a message you’ve received as spam … but some of them make it far TOO easy to report something as spam.

I’ve noticed that many of the big names put the “Report as spam” button way too close to the delete button.

Let’s take a look at some of the providers …

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