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Updated Free SfBO and Microsoft Teams Network Assessment Tool, Added Connectivity Tests to Microsoft Teams Services

Published 10/12/2017 - 2 Comments

A new Tech Communities post from William Looney highlighted that Microsoft has updated their free network test tool.


Version: 2017.1.0.51

File Name: MicrosoftSkypeForBusinessNetworkAssessmentTool.exe

Date Published: 12/8/2017

Download link:

I previously looked at the tool in this blog post if you want an overview.

The tool tests the connection to Microsoft Network Edge by streaming a set of packets to the nearest edge site and back for approximately 17 seconds for a configured number of iterations. Testing:

  1. Network performance – Test the connection to Microsoft Network Edge by streaming audio packets to the nearest edge site and back for approximately 17 seconds for a configured number of iterations. The tool collects, packet loss, jitter, round-trip latency and packet reorder percentage from each call. The results from set of test calls can be analyzed to determine if it meets the media quality and performance targets described here: . These targets and testing apply for both Microsoft Teams and Skype for Business Online calls.
  2. Network connectivity – Verify network and network elements between the test location and the Microsoft Network are correctly configured to enable communication to the IP addresses and ports needed for Microsoft Teams calls. The addresses and ports are described here: These tests are performed using UDP and TCP transport protocol.

17 seconds seems like an oddly specific amount of time, I’m not sure why that is.

This new version has the following new features:

  • Perform connectivity test to all of the IP addresses and ports used in Microsoft Teams calls/meetings. This enables you to ensure the firewalls or other network equipment are correctly configured. The tool auto updates the list, so if any addresses or ports changed, the next time the tool is run, the new addresses will be included.
    Previously the tool did a simple relay test to the Microsoft Network edge. It’s explicitly noted these are Teams services not Skype for Business, so this is only a valid test for Microsoft Teams.
  • Tool is now delivered as an .exe which will install the appropriate runtime dependencies. This should help ensure the tool runs as expected. As part of this, the default path the output files are written to has changed.
  • Updates to support changes in relay management

Note, the old version will stop working so please update to the latest version.

The new version has a nice installer. It Installs to this path:


It’s still a cmd exe, by default it runs the network test:


Output in the same Tab separated table format.


“NetworkAssessmentTool.exe / connectivitycheck” runs the connectivity check




We can see through Netmon it does indeed go and grab a config file from the service telling it what to test and tests against a whole range of URL’s and IP’s. Service names tested:

  • ConversationService on [various]
  • ChatService on [various]
  • TrouterService on [various]
  • PresenceService on presence.[various] and [various]
  • BrokerService on [various]
  • TransportRelayService  on various IP’s, ports: “relayPortUdp”:3478, “relayPortTcp”:443, “relayPortUdpAudio”:3479, “relayPortUdpVideo”:3480, “relayPortUdpVbss”:3481

This will be really useful for testing in environments where firewalls are tightly locked down.


Tom Arbuthnot

Tom Arbuthnot

Principal Solutions Architect at Modality Systems
Tom Arbuthnot is Principal Solutions Architect at Unified Communications specialist Modality Systems. He is a Microsoft Certified Master and MVP, blogger, has a regular podcast with UCToday at and is a regular speaker at events including Microsoft TechEd and Ignite. He co-runs The Microsoft UC User Group London.


Joshua Yadron - 14/12/2017 Reply

Thanks, your write-up helped me figure this out. One thing I might add is /verbose flag puts all IPs and ports it checks against right into the output file.

Oliver Radcliffe - 09/02/2018 Reply

Is there a similar test to test Skype for Business connectivity? Prior to making DNS changes for a cutover scenario of on-prem to online, so I don’t believe Remote Connectivity Analyzer will be helpful.

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