Email rejections

The bulk email I mentioned in this earlier post didn’t work out as well as I’d hoped. The cut-and-pasted encoded PDF attachment—the main topic of the post—was fine, but several of the messages were rejected. The problem was Sendmail and spam.

I’d forgotten that when you send an email directly from your own computer using sendmail (which on the Mac is actually Postfix acting in Sendmail’s stead) the receiving mail server sees it as coming from you instead of a known server. Some servers are OK with this, but some automatically reject such messages, figuring that they’re likely to be spam.

I had come up against this issue several years ago when I used Linux as my desktop OS and sent mail out directly from it via Exim. I had a way around it back then, but can’t remember at the moment how I did it. So today I just resent the rejected messages “by hand” through Mail. If I find myself needing to do bulk emails like this again, I’ll do a little Googling for the workaround.

Update 6/5/10
The ever-helpful Tanja has pointed out in the comments that you can get Postfix to use your ISP’s mailserver (so other mail servers see your messages as coming from a “legitimate” source) by adding one line to your /etc/postfix/

relayhost =

Make sure the server name you give is your ISP’s SMTP (outgoing mail) server. There’s a section of commented-out relayhost examples about halfway through

Using GMail as your mailserver is more complicated, because it uses nonstandard ports and a security layer. This article has what step-by-step set of instructions.

2 Responses to “Email rejections”

  1. Tanja says:

    I’ve edited /etc/postfix/ and added: relayhost =

    This makes postfix send all the mail through my isp’s mailserver.

  2. Dr. Drang says:

    Tanja, that’s exactly what I need. Thanks.