How can I make my domain and emails less suspicious?

November 28, 2004 8:04 PM

I'm building a website that programatically sends users a confirmation email during signup, but the emails are being blocked by the recipients' mail server, I assume because my domain name is failing some anti-spam test. How can I make my domain and emails less suspicious? [MI]

I'm an undergraduate, and the site is for students at my university. Membership at the university is validated by confirming a university email address. Experimentation shows that the emails pass through fine to yahoo and gmail accounts, but don't to university ones. Since the content isn't spamlike, I'm assuming that they're being blocked because I'm sending from a recently aquired personal domain, which could understandably seem spamish. Is there a way to make my domain, and thus emails, become trusted members of the email system?

posted by gsteff to Computers & Internet (8 answers total)

A trick used on me a while back (by spammers) was to make their sending/return address the same as my address.

However, nowadays this might cause the opposite problem. Are you programatically changing either the sending or return address? The server might think you're spoofing (which you technically are....)

For example, I wrote a program once that would send mail from [e-mail]. Using PHP I changed that to show up as [e-mail] (it was a virtual webhost). That worked then, but now mail servers might have problems with that sort of thing today.

Just a guess.
posted by zelphi at 8:10 PM on November 28, 2004

Make sure reverse DNS lookups work correctly for your domain. If that is an impossibility (i.e. you are using virtual hosting on a machine that is shared by many others), then see if you can use your hosting provider's SMTP server for sending out mail. Their SMTP server should provide forward and reverse domain lookups.

Look at the form letter you are sending as confirmation, and see if there's anything in there that would make a bayesian filter mark it as spam. Do the words VI@6R@ , or Nigeria, etc. appear in the form letter? Even things like "Dear Sir/John/Mary" often get pegged by bayesian filters. Wording that sounds like a normal e-mail exchange between friends will tend to do a better job getting through.
posted by stovenator at 8:11 PM on November 28, 2004

You don't say what language you're using, but after encountering this same problem in PHP I poked around on the internet some and came up with the following (the headers are what's important, of course):

mail($email, $subject, $message,
"From: Your Website <[e-mail]>\n" .
"Reply-To: [e-mail]\n" .
"MIME-Version: 1.0\n" .
"Content-type: text/plain; charset=iso-8859-1\n" .
"X-Priority: 3\n" .
"X-MSmail-Priority: Normal\n" .
"X-Mailer: PHP/" . phpversion());

Googling and my memory fail me at the moment, but I think that X-Priority and X-MSmail-Priority did the trick for Hotmail, which was the main culprit.
posted by rafter at 8:14 PM on November 28, 2004

Talk to the university's IT dept. An anti-spam measure is most likely, but that doesn't narrow down the possible solutions by much. IT will be able to check the logs to identify the specific reason you're getting blocked.
posted by nakedcodemonkey at 9:29 PM on November 28, 2004

Put the IP address of the server you're sending mail from through the Spam Database Lookup tool at dnsstuff. This should tell you which anti-spam services have your server blacklisted. If your mail server's address shows up here, contact your web host and see what they can/will do about getting your server off of the list. If you're using shared hosting, odds are somebody else on your server triggered the spam alarm. Solutions range from the web host dumping the spammer and contacting the antispam service to get you removed to moving you to a clean server. Another option is to try to get the university to whitelist your domain address.
posted by SteveInMaine at 11:50 PM on November 28, 2004

You're not using the To: address in the From: as well, are you?
posted by yerfatma at 4:21 AM on November 29, 2004

I think Rafter's answer is the most likely. If you are failing an anti-spam test, it's probably not because you're listed in any known spammer database, but because your headers are suspicious. Anything not sent by a standard MTA is almost always flagged by the major anti-spam software, including SpamAssassin. If a spam system has "number of points to qualify as spam" set low, then your messages could be dumped.

Also, I'd recommend that you make it plain text, not HTML, if that's what you're using. Using HTML alone can be enough to accrue sufficient points to trigger a spam filter (depending, of course, on the system, points ceiling, and other factors).
posted by Mo Nickels at 8:50 AM on November 29, 2004

Mail handling is entirely the recipient's responsibility. It is not your job as the sender to make sure your messages get through overzealous spam filters, but rather the recipient's job to make sure their filters are not blocking mail that they want to receive.

That said, you could change the validation system so that it assumes the mail has been delivered unless it receives an explicit bounce notification.
posted by kindall at 9:35 AM on November 29, 2004