Please note that the complete list of IP ranges and ports can be found at Office 365 URLs and IP address ranges.The changes to the IP and port ranges were added in August, but now is a great time to go back and review your firewall and other security devices to ensure they are being allowed as we move ahead with the deployment. New ports: While this might take a little bit more time than the new IP ranges, we will leverage the following ports for media traffic in addition to the existing ports:.The ranges are required in addition to the existing ranges, so remember to open all IP ranges documented in Office 365 URLs and IP address ranges. New IP ranges: We already started to move the Skype for Business infrastructure to new ranges.

We strongly recommend to open the IP subnets and ports today, to avoid any negative impact to connectivity. Skype for Business Online has a significant infrastructure, so while we have started with these changes, it will take some time to be completed. To address this feedback, Microsoft decided to perform several optimizations to simplify the requirements. We heard from some of our customers recently, that the number of IP ranges and ports required for Skype for Business make it complex to configure firewalls. Updated IP ranges and ports for Skype for Business Online

For more details see: Simplified port requirements for Skype for Business Online

Firewall ports for skype for business