Microsoft have added additional IP’s to Office 365 and EOP, so if you get mail delivered On-Prem from 365 be sure to get the following IP’s added to your Firewall and Exchange Connectors!
Additional IP’s are as follows:
- 40.96.0.0/16
- 40.97.0.0/16
- 40.98.0.0/16
- 40.99.0.0/16
- 40.100.0.0/16
- 40.101.0.0/16
- 40.102.0.0/16
- 40.107.0.0/16
- 204.79.197.215
- 131.253.33.215
- 191.234.6.152
- 206.191.224.0/19
- 23.103.224.0/19
- 40.103.0.0/16
- 40.104.0.0/16
- 40.105.0.0/16
Be sure to get these IP’s added in the relevant places as you only get a 30 day warning period before Microsoft start using these IPs!!!