CheckTLS WhiteList

Add the following IP addresses and domain names to any network filters and/or domain Whitelists at your site.

IP Addresses:

WWW*//email/testTo: ("TestReceiver") originate from here
www11-do.checktls.com 167.71.160.115
  2604:a880:800:c1::1ca:9001
www12-do.checktls.com142.93.73.156
  2604:a880:800:c1::5d:a001
www12-azure.checktls.com40.76.159.115
  2603:1030:20e:3::136
www14-azure.checktls.com20.75.92.112
  2603:1030:408:4::200
 
MAIL*test emails originate from here
mail11-do.checktls.com 134.209.47.28
  2604:a880:800:c1::277:e001
mail12-do.checktls.com104.131.118.193
  2604:a880:800:14::13e:a000
 
MAILBOX*support and staff emails originate from here
mailbox1-do.checktls.com 104.131.168.30
  2604:a880:800:14::177:c000
 
TS*//email/testFrom: ("TestSender") are sent here
ts11-do.checktls.com 165.227.190.238
  2604:a880:800:a1::e95:1001
tsa11-do.checktls.com 134.209.169.224
  2604:a880:800:c1::2f1:5001

Domain Names:

CheckTLS.com
*.CheckTLS.com

Adding our IP address range to any network filters makes sure our tests are able to do the testing you request from our site.Our tests are non-invasive, non-intrusive, and non-obtrusive. They require no changes to your or any other system. They cause no extra processing and should not trip any security alarms.

Adding our domain to any Whitelists also makes sure our tests can do the testing you request, and it also makes sure any results we email to you get through to you and don't end up in a junk folder or thrown away.