mail() not ending up in spam

So I'm wondering if there's anyone that might know a solid script that won't send a mail() to the spam box regardless of the type of host the person uses for an e-mail account. Even if it resorts to absolute simplicity I'd be okay with that rather then a fancy HTML mail with full headers (but if I could use that it would be cool too).

BUMP!

I'm trying to send a confirmation an order was shipped but 99% are being bounced back as spam

ANY HELP!?????

It depends on a variety of factors, what are you setting the "FROM: " header as? If for example you set it to yourname@hotmail.com and send it to a hotmail address, microsoft know it didn't come from hotmail and marks it as spam.

The most common reason is when your mail server does not have all the correct DNS records (missing or wrong SPF, MX, or A records will get an email voted as SPAM). The second most common reason is what cags posted, a From: address that is not hosted at the sending mail server (if you were a receiving mail server and the From: address could not have come from the actual sending mail server, would you put the email into the 'in' box?). The third most common reason is short messages and subject lines that also contain spam like content (links, spamy words...) Another reason is if your mail server has been used in the past to send spam to the receiving mail server and has been blacklisted or appears on any of the spam databases.

All of these things don't really have much to do with finding a 'correct' script to use, but how well your mail server is configured, what you put into the mail header fields, and what you put into the subject and message.