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SFB UDP Ports

Copper Contributor

Hi Team,

 

I would just like to get your expert inputs on this. Currently, UDP Ports :3478, 3479, 3480, 3481 are not allowed in our firewall, would there be any issues if we will allow these ports to our network? 

 

Also, can you tell me what is the purpose of these ports: UDP: 3478, 3479, 3480

 

Issue: We are experiencing high latency with our Skype calls and we are under the impression that these ports would make our connection better. Reference: https://docs.microsoft.com/en-us/office365/enterprise/urls-and-ip-address-ranges#skype-for-business-...

 

Appreciate your quick response.

 

Thanks!

 

Will

6 Replies
best response confirmed by WilliamTan30 (Copper Contributor)
Solution

Hi Will,

 

The ports you mentioned are used for the realtime communication part (e.g. Audio, Video, Sharing) of SfB and Teams. So you should definitly use/allow them. If you don't open them, there is a fallback used via Port 443/TCP. This is the mode your environment currently running in.

 

These ports fall in the category of optimize. You can find the recommendations for this kind of traffic here:

https://docs.microsoft.com/en-us/office365/enterprise/office-365-network-connectivity-principles?red...

 

If you are planning a change with the network Team I would recommend the Network Testing Companion. This allows you to simulate calls and test network connectivity for these ports.

You can find a blog article from @Erwin Bierens how to install this here: https://erwinbierens.com/skype-for-business-and-microsoft-teams-network-testing/

 

Regards,

 

Paul

 

 

@Paul Lange Thanks for the prompt response. I tried installing this tool but i could not find it in my desktop nor in my program, I am now stock in step 6. Do you know where will I find it? Please see attached.

 

I tried searching it through "search bar" and newly installed program but its not there.

 

Thanks!

*Stuck*

If you can't find the shortcuts, try this to start the Tool:
Windows + R and then paste %SystemRoot%\system32\WindowsPowerShell\v1.0\powershell.exe -WindowStyle Hidden -Command & {Invoke-NetworkTestingClient}

@Paul Lange I found it! :) Thanks! I've managed to run a test and got the attached result.

 

May I know what are the advantages and disadvantages of allowing these ports?

 

Forgive me for being inexperience :)

 

Thanks!

 

Will

 

 

Sure Will. No worries.

Allowing these ports will allow Teams and SfB to use UDP instead of TCP for transmitting realtime traffic (e.g. Audio/Video).
UDP can deliver packets faster to the far end than TCP (avoiding error checks) and performs better in problematic network conditions. This is the reason why in the Unified Communication space UDP is prefered over TCP for the audio and video part.

Hope this helps.

Paul

1 best response

Accepted Solutions
best response confirmed by WilliamTan30 (Copper Contributor)
Solution

Hi Will,

 

The ports you mentioned are used for the realtime communication part (e.g. Audio, Video, Sharing) of SfB and Teams. So you should definitly use/allow them. If you don't open them, there is a fallback used via Port 443/TCP. This is the mode your environment currently running in.

 

These ports fall in the category of optimize. You can find the recommendations for this kind of traffic here:

https://docs.microsoft.com/en-us/office365/enterprise/office-365-network-connectivity-principles?red...

 

If you are planning a change with the network Team I would recommend the Network Testing Companion. This allows you to simulate calls and test network connectivity for these ports.

You can find a blog article from @Erwin Bierens how to install this here: https://erwinbierens.com/skype-for-business-and-microsoft-teams-network-testing/

 

Regards,

 

Paul

 

 

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