Too often, network issues are blamed for poor performance of Microsoft Teams calls, meetings, and video conferences.  However, if you address the five things that Johan identifies, you can eliminate many of these problems.  The guiding principle here is that Office 365 network traffic should go as directly as possible between your end user computing devices and Microsoft’s global network.  To achieve this,  your organization’s network engineers need to do these five things:


  1.  Check the reverse proxy.   No network traffic bound for Office 365 should go through your reverse proxy. Exclude everything that goes to Office 365 from the proxy.  Allow Office 365 outbound traffic to go directly through the firewall on your company’s network.
  2.  Check your company’s firewall.  You need to ensure that all Office 365 Internet Protocol (IP) addresses and all required network ports are permitted through the firewall.
    1. For both #1 and #2 above, you will need a list of those ports and IP addresses. Fortunately, Microsoft publishes these.  Unfortunately, these change periodically, so you will need to monitor for changes.  The list of URLs, ports, and IPs is carefully documented at https://docs.microsoft.com/en-us/office365/enterprise/urls-and-ip-address-ranges. Furthermore, there is now a web service that provides these lists, so you can automate updating your firewalls and proxies. Some firewall and proxy vendors have built into their products the ability to get updates from this web service.
  3.  Do not route through VPNs.  O365 communication should go directly from the end user to Office 365, not over VPNs. End users working remotely may VPN into your corporate network.  Remote offices may have VPN connections to connect their local office network to the corporate headquarters network.  Configure your VPNs so that Office 365 network traffic, which is already encrypted, does not route through the VPN tunnels, but rather routes directly to the internet.
    1. IGNITE-2018-THR3081-TrustO365.jpgWhen you have all your firewalls and proxies properly configured, your company network trusts the Office 365 cloud the same way it trusts on-premise assets.  



  4. Minimize Roundtrip delay. Similar to the rule about not routing through VPNs and sending Office 365 traffic directly to the internet, make sure that your internet service provider has direct access to Microsoft’s global network. This is true for not just the ISP that serves your corporate headquarters but for the ISPs that serve your local offices too. Make sure your local offices have direct internet connections.
  5.  Test and if needed improve QoS.  Make sure any unified communication traffic happening within your network is not being routed out of your network only to come back in again. Make sure any internal firewalls permit this.


There’s a tool called the Skype for Business Network Assessment Tool that works for Teams too and you can download for free from Microsoft.  It helps with assessing items #4 and #5 above.


Watch Johan’s session for more information!





About the Presenter

Johan Delimon Small.pngMVP Johan DelimonJohan works for large international System Integrators and Hosting Companies.  His focus is Skype for Business, Enterprise Architecture and Technical Leadership. He has been a Microsoft MVP since 2008 and is currently a Microsoft MVP for Office 365.  He is one of the few Microsoft Certified Masters (MCM) in the world for Lync.





About the Blogger

image005.jpgMVP Michael BlumenthalMichael Blumenthal is a Microsoft Office 365 MVP and the Digital Workplace Product Manager at West Monroe Partners, where he is responsible for product management and service management of Office 365. He helps teams of business people be more productive and ensures that the organization gets value from its Office 365 investment. As a technical community leader, he co-leads the Office 365 Adoption User Group and organizes their bi-monthly meetings as well as special events. As a public speaker, he can be found speaking on business technology topics including business productivity, collaboration, knowledge and expertise management, communication and content management, cloud adoption, and Office 365.  

1 Comment
Occasional Visitor

Any support at all for OS X devices?