Block ALL EXTERNAL TEAM contacts from messaging users in your @domain.com

[minja20]

Greetings Folks,

I am new to the community and apologies if this has been answered already but I couldn't find any previous conversations on this specifically.

My question: How can we BLOCK ALL EXTERNAL contacts from messaging our INTERNAL contacts in MS Teams (Cloud)? For example, only domain users @ABC.com could talk to other users. Any other chat requests from @XXX.com will be blocked by default. 

I ask because I think this could pose a security risk and various other reasons.  Thanks for reading and sharing your comments in advance.  

Cheers,

IT Guy

[#2 · Accepted solution]

@minja20 

Chat can be disabled for all Guest users using the settings in the Teams Admin Center.  See

https://docs.microsoft.com/en-us/microsoftteams/manage-guests#:~:text=Guest%20access%20licensing%20l...

for more details.

[#3]

@bryanhart thanks very much for details. 

[#4]

Beside the ability for guest users you should also configure the federation capability to meet your needs.
https://docs.microsoft.com/en-us/microsoftteams/manage-external-access