cPanel DKIM Keys Not Compatible with IIS

PostAlmostAnything

• March 03, 2020 19:04

I have a network of websites hosted on a IIS server that use an external Linux server with cPanel for email. The reason it is setup like this is because my Windows hosting company would not configure rDNS without a data center change, I already had a Linux server for a PBN anyway, and I prefer cPanel to hMailServer. It works great except for one problem. Whenever I install the cPanel DKIM key on the IIS server it does not work. The error I get from various DKIM checking tools such as Mail Tester is something along the lines of not being able to retrieve the key length, the length being invalid, or too long. I had this problem when installing DKIM keys for use with hMailServer whenever the key I generator at Spark Post was set to 2048 bits. When I changed it to 1024 bits the keys it generated worked just fine. This brings me to my current situation: - Does cPanel generate 2048 bit keys or 1024 bit keys? - Can cPanel generate 1024 bit keys instead of 2048 bit keys and if so, how can I do that? - Can I install a Spark Post key in cPanel and use it instead of the one generated by cPanel? - Can 2048 bit keys be enabled on IIS?

• 

  cPanelLauren

  • March 04, 2020 17:25

  Hello,

  - Does cPanel generate 2048 bit keys or 1024 bit keys?

  
  Mail Tester shouldn't have a problem with cPanel's DKIM keys which are indeed using 2048, we split them automatically if they're too long. I'm using a 2048-bit key and not able to replicate an issue with mail-tester. -25-31.png">63877

  - Can cPanel generate 1024 bit keys instead of 2048 bit keys and if so, how can I do that?

  
  We only generate the 2048-bit keys, you are welcome to create your own DKIM key but that shouldn't need to be done at this point.

  - Can I install a Spark Post key in cPanel and use it instead of the one generated by cPanel?

  
  You can, though again this shouldn't be necessary, the record should be split automatically in the event it's too long which should be recognized everywhere. SparkPost does generate 2048-bit keys as well

  0
• 

  PostAlmostAnything

  • March 04, 2020 21:37

  I found some hacks on this forum that I was able to use to make cPanel produce 1024 bit keys. They seem to be working well.

  0
• 

  PostAlmostAnything

  • March 04, 2020 21:38

  Hello, Mail Tester shouldn't have a problem with cPanel's DKIM keys which are indeed using 2048, we split them automatically if they're too long. I'm using a 2048-bit key and not able to replicate an issue with mail-tester. -25-31.png">63877 We only generate the 2048-bit keys, you are welcome to create your own DKIM key but that shouldn't need to be done at this point. You can, though again this shouldn't be necessary, the record should be split automatically in the event it's too long which should be recognized everywhere. SparkPost does generate 2048-bit keys as well

  0
• 

  PostAlmostAnything

  • March 04, 2020 21:41

  Here is link to what I used on this forum. I just logged into WHM and acessed the terminal. Then I used the methods decribed in this tread to set my min key size to 2024, delete to old keys, and generate new ones.

  0
• 

  PostAlmostAnything

  • March 04, 2020 22:18

  Great, now when I e-bomb my users I get this: End of Recipients Message Sent End of Inner Exceptions End of Failed Recipients Smtp Exception: ServiceNotAvailable Smtp Error Message: Service not available, closing transmission channel. The server response was: too many messages in this connection Smtp Exception: ServiceNotAvailable Smtp Error Message: Service not available, closing transmission channel. The server response was: too many messages in this connection Smtp Exception: ServiceNotAvailable Smtp Error Message: Service not available, closing transmission channel. The server response was: too many messages in this connection End of Smtp Exceptions End of Exceptions I tired changing the maximum emails per domain per hour from 500 to unlimited but still got the same error.

  0
• 

  PostAlmostAnything

  • March 04, 2020 22:19

  Also, I maintain several user accounts so I can check if the message is received and I have not gotten any.

  0

Please sign in to leave a comment.