Details for ‘whitelisting’ email software

Whitelisting is the practice of providing a list of approved software applications or other components that have been explicitly permitted to be present and used with your computer system.

If you use software or services that try to decide if email content is spam, phishing or similar and blocks it as a result, then you may need to add exceptions in this software.

For various reasons these sorts of programs don’t always get it right, but fortunately there are ways that you can tell it that content is legitimate no matter what it might think.

Exactly how you configure the software or service can vary, so we can’t provide general instructions. However, this page aims to provide you with the technical information that we believe you will need. Hopefully your IT team will know what to do with this information, but if there are any problems then please do contact us.

We use three different services to send a variety of emails:

  • Postmark send the majority of our emails including account emails (eg: password reset) and notification emails (eg: new post, approval request, etc.).
  • Campaign Monitor is used for our newsletter services.
  • Amazon SES is used when users want to send personal emails via the ISTATOY (I saw this and thought of you).

IP Ranges

The following IP address ranges are used to send email on our behalf:

Postmark

  • 50.31.156.96/27
  • 104.245.209.192/26
  • 50.31.205.0/24

Campaign Monitor

  • 27.126.146.0/24
  • 103.28.42.0/24
  • 146.88.28.0/24
  • 163.47.180.0/22
  • 203.55.21.0/24
  • 204.75.142.0/24

Amazon SES

  • 199.255.192.0/22
  • 199.127.232.0/22
  • 54.240.0.0/18

From Addresses

If your filters work on From or Sender addresses, here are the ones we use for sending:

  • passle.net
  • *.passle.net
  • passlemail.net
  • passle-mail.net
  • amazonses.com (This will only ever be a sender address.)

If you need any other information, please get in touch via technical@passle.net and we will do our best to help make sure you have everything you need to ensure reliable delivery of your emails.