Teams Call Blocking

call blocking

Written by Dan Callahan

I am a Senior Technical Advisor to CGNET. Formerly, I managed our Cybersecurity and Cloud Services businesses, and provided consulting to many clients over the years. I wear a lot of hats. Professionally, I'm a builder of businesses. Outside of work, I'm a hobby farmer, chef, skier, dog walker, jokester, woodworker, structuralist, husband and father.

May 9, 2019


Did you know you can use Teams to block calls?  I get a fair number of spam calls on my office phone as well as on my mobile phone.  There are utilities, such as Nomorobo, that can be used to block these calls.  Unfortunately, they don’t work for IP based phone systems.


Teams block call


I had begun to think that I was just going to have to get used to receiving a call in every morning from one of my favorite spammers.  But then I happened to be looking at the call history menu in Microsoft Teams. I clicked on the ellipsis (…) next to the spam call number and discovered that one of the actions was “block.” Well, you don’t have to ask me twice! I selected block and gave a fist-pump for the forces fighting the scourge of spam calls.

My victory was short-lived.

Yes, you can use the Teams client (web and PC; I haven’t seen this feature in the iOS client) to block calls. But, as you can also see in the screen shot, the spammers simply incremented their spoofed number by one and returned to calling me. So, I blocked that number. And they incremented their spoofed number again. And called me again. I may continue blocking their number, seeing if I can outlast their number pool. Or I may go back to ignoring their calls.

Side note: Clearly, blocking spam calls one by one, after they’ve called you, is not the best way to attack the problem. Someone could gather information about the calling party, such as frequency of outgoing calls, call duration and the like. They could then use that information and machine learning to come up with a way to predict which calls are robocalls.

No More “Islands Mode” for Me

Incidentally, I had my Skype-Teams “coexistence mode” (defines how you want Skype for Business and Teams to coexist in your organization) changed from “islands mode” to “Teams only.” The results have been great. Previously, I could use Teams to make outgoing phone calls (the other Teams features worked as well.) But I couldn’t receive phone calls from public numbers unless I had my Skype for Business client running. (I discovered this one day when missed call and voice mail notifications kept showing up in my email.)

Now I’m done with that. The only time I need to use Skype for Business is when I’m joining a Skype for Business call organized by someone else. And even here, I can join with the Skype Web Client. So adios Skype for Business client; it’s been nice knowing you.

You May Also Like…

You May Also Like…

1 Comment

  1. MJ

    Thank you for sharing how to block incoming phone calls on VoIP in Microsoft Teams. This was very helpful

Translate »
Share This