Check DomainKeys, DKIM, SPF valiadity, and SpamAssassin score in one place

Posted on September 28th, 2007 in General,Mail by Brandon

I spent the whole day today stepping through DomainKeys, DKIM, and SPF for a customer to make sure that they were all set up and working properly. I found a couple of the existing tools available on the Internet didn’t test them properly and didn’t give enough explanation when they failed.

So, I went about creating some of my own tests using a bunch of Perl modules. I finally fixed a couple issues that I think were causing problems for this customer. Gmail and Yahoo are now delivering the messages anyway. Hotmail is still a mystery (no surprise since its from Microsoft). Their troubleshooting website is full of talk about how great their service is, but there is a huge lack of anything technical on the site.

Anyway, I made all of these nifty testers and figured that others might like to use them. So I created a way for others to send mail to it, and a web interface that you can view all of them results. I’ve added it as a link to the top of my website.

8 Responses to 'Check DomainKeys, DKIM, SPF valiadity, and SpamAssassin score in one place'

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  1. Adrian said,

    on January 27th, 2009 at 6:35 am

    Here is a good tool regarding to this post

  2. Randy Owens said,

    on July 30th, 2009 at 4:13 pm

    Just a little suggestion for the SpamAssassin setup you use for checking on that page. It might be a good idea to turn off the auto(white|black)listing on it, so people aren’t getting hit with modifiers because they’re already sent off a few tests, like right now I’m getting “-1.3 AWL AWL: From: address is in the auto white-list”.

  3. Brandon said,

    on July 30th, 2009 at 4:24 pm


    Great idea, thanks. That has been implemented now. I also found this post that describes how the auto-whitelist works

    The Problem With Spamassassin’s AutoWhitelist Feature

  4. OmegaSharp said,

    on October 14th, 2009 at 5:14 pm

    I sent an email as via relay Your tool checks for SPF records. Is this the correct way? Or shall I ask to add such a SPF record?

  5. Brandon said,

    on October 14th, 2009 at 7:29 pm


    I’m not sure I follow what is going on. If you are sending a message with an envelope sender of ‘’, then you should have an SPF record for that specifies that is permitted to send mail from your domain name.

  6. Adam said,

    on November 18th, 2010 at 4:13 pm


    Just wanted to say THANK YOU for this great tool! I’m a DKIM noob and it helped me debug my problem.

  7. Christina said,

    on June 28th, 2011 at 6:37 pm

    Hi, great post, just used this to check my DKIM and SPF. Love the idea that you don’t have to keep resending the message.

    However I’ve noticed that the SPF test sometimes returns “Result: PermError (Included domain ‘’ has no applicable sender policy)”, and other times returns “Result: Pass (Mechanism ‘’ matched)”? (on the same email, no DNS changes, with in the SPF record). Is that an issue with the test, or an issue with Google’s servers?


  8. Zlawa said,

    on January 5th, 2012 at 6:11 am

    Can you release your implementation of this “email tester”?

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