If you're having trouble either receiving your own emails or accessing our software, you may want to ask your IT team to whitelist our addresses.

Return-path sending domains

Instead of whitelisting all of our sending IP addresses, you can whitelist our domains. 

They currently include cmail1.com through to cmail20.com.

Sending IP Addresses

Below are the IP ranges we use for sending email:

• 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

If your software or equipment doesn't allow the /22 notation, 163.47.180.0/22 is equivalent to:

• 163.47.180.0/24
• 163.47.181.0/24
• 163.47.182.0/24
• 163.47.183.0/24

Upcoming IP addresses

While not currently in use, the following block of IP addresses will be used in the future to deliver emails.

ipv6 2404:DE00::/32

SPF

While we handle SPF for you, some anti-spam services on your local network may be particularly strict, requiring our domain to be added to your own existing SPF record. In this case, you can add the following: