Email White Lists / Avoiding Spam Filters

A few weeks ago asked to find out why some of our users were not getting email from our web site. My first thought was that I did everything I needed to do already and that there was not anything we could do to make our mail be accepted by recipient mail servers. Long story short, I found a few things that I could quickly do to make a difference.

Here are a few simple things I needed to change:

  1. Make sure your mail server has reverse DNS.
    its pretty strait forward, all you have to do is contact your ISP and ask them to delegate the reverse dns to you. I set them up in about 15 minutes. I found out that AOL email servers will not accept email from servers that do not have their reverse dns setup. To see if your server is setup you can go to: http://postmaster.info.aol.com/tools/rdns.html
  2. Make sure your email headers are not throwing red flags.
    I had to make a couple of changes to the postfix main.cf file because it was sending the mail from domain.com instead of the correct relay.domain.com.
  3. Add a SPF entry to your dns zone.
    I was doing a test on one of those cool DNS testing sites and saw that I should have my SPF configured. I had no idea what it even was and then I search google and found this site http://spf.pobox.com/wizard.html?mydomain=domain.com&x=24&y=6. from there I just completed the wizard and edited my zone files and I was good to go.

Of course there are many other things I have done to ensure the legit email I send is not counted as spam, but these were three things that caught me by surprise.

I’m no mail server expert, but with the help of AWStats I can see now that email is being sent and there are 90+% less errors.

Numbers likes these are hard to ignore… (wasn’t that on a TV commercial? 😉

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