When using the mailRelay service you may wish to lock down which IP addresses your SMTP server connects to.
If locking down the IP addresses please ensure that you can connect to TCP/25, TCP/587 and/or TCP/2525 within the following blocks:
- 185.54.84.0/22
- 193.203.116.0/23
- 145.239.203.48/28
- 178.32.81.96/28
- 77.74.195.96/29
- 51.38.77.48/29