External & Guest Communication in MS Teams

As more and more of our working life is conducted virtually and we communicate more using Microsoft Teams with internal and external people, it can be a challenge to determine which features we can use with whom. As I write this it’s June 2020 and COVID-19 is still impacting many working practices, but this digital life isn’t new and isn’t going to go away either.

The official guidance on https://docs.microsoft.com just wasn’t giving me answers that matched what I was seeing in real life, so I set out on a mission to try and put together a more comprehensive guide to what works in which situations. 

HOWEVER: it’s complicated and ever changing, so please do comment on this post if you find something that you disagree with or has changed.

First a few definitions of terms I’m going to use in this guide:

  • Internal User – A person in the same organisation as you, who has a 365 license.  Normally has the same email suffix as you (the bit after the @ sign)
  • Guest User – A person in a different organisation, who has been added as a recognised user for your organisation.  They may have been invited to join a team, had a document shared to them or have been manually added as a guest by an administrator.  A more technical definition is that they have been added to Azure AD as a Guest/External User, do not have a license on your tenant and log in with an identity that is not managed by you (e.g. another organisations Office365, Gmail, Facebook or a Microsoft account)
  • External User – A person in a different organisation, with whom you communicate. Also known as a federated user
  • Chat – Messaging and calls from the Chat in Microsoft Teams.  This can be 1:1 or small groups.
  • Meeting Chat – Chat which accompanies a Teams meeting.  Unfortunately for these definitions once someone posts a message in the meeting chat, these chats are also available from Chat in Teams. These are different to 1:1 or group chats though.
  • Teams Posts – The chat which is part of a Team channel and only available to member of the team. 

This guide looks at communication which is Teams to Teams, no Skype of any kind is covered.  It is possible for administrators to restrict these features with different policies and settings in Teams and Azure AD, but to try and keep it simple I’ve assumed all communication is permitted at both ends of the conversation, which means:

  • No blocked domains at either end (called Open Federation) , or at least users at either end are permitted/not blocked
  • Azure AD Guest Access is permitted and guests can be invited by users not just admins
  • Policies and Teams settings permit communication with Guest and External Users including anonymous meeting join without restrictions

In Summary:

ActionInExternal UserGuest UserInternal User
Send Chat MessageChatYesYesYes
Make a Voice Call in ChatChatYesYesYes
Make a Video Call in ChatChatYesYesYes
Be Added to a Group ChatChatNoYesYes
Share Files in Chat using PaperclipChatNoNo2Yes
Share Files in Meeting Chat using PaperclipMeetingsNoYesYes
Share Files in Teams Posts using PaperclipTeamsN/A1YesYes
Share Screen in a Call or MeetingChatYesYesYes
Share Screen in a Call or MeetingMeetingsYesYesYes
Respond to a Poll in Meeting ChatMeetingsNoYes3Yes
Respond to a Poll in Teams PostsTeamsN/A1Yes3Yes
Use Meeting NotesMeetingsNoYes3Yes
Start RecordingMeetingsNoNoYes4
View Meeting RecordingMeetingsNoNoYes
Contribute to Meeting NotesMeetingsNoYes3Yes
View Meeting WhiteboardMeetingsVia Shared Screen onlyYes3Yes
Contribute to Meeting WhiteboardMeetingsOnly if given ControlYes3Yes
Use @ MentionsChatYesYesYes
Use @ MentionsMeetingsYesYesYes
Use @ MentionsTeamsYesYesYes
Use Fun Stuff – Emojis, Gifs & StickersChatYesYesYes
Use Fun Stuff – Emojis, Gifs & StickersMeetingsYesYesYes
Use Fun Stuff – Emojis, Gifs & StickersTeamsYesYesYes
Send Audio Messages from Mobile App in ChatChatYesYesYes
Send Audio Message from Mobile App in Meeting ChatMeetingsYesYesYes


1
External users who are invited to a Team become guest users

2 it is partially possible to share files with guest users using the paperclip.  If UserA is added as a guest in your tenant (either by being manually added or invited to a Team), and you message UserA(Guest) in your tenant, you can share files using the paperclip.  However UserA(Guest) cannot share files to you.  You also cannot share files in the chat from your own tenants using the paperclip.  A workaround is to upload the file into your OneDrive and generate a link which you can share in the chat.  Sharing a file to specific users automatically sends them an email, which is the simplest method, though this does not keep the conversation in Teams.

3 When joining meeting from the guest tenant.  This means using Teams in the browser, switching to the guest tenant then pasting the join link into different tab and joining the meeting in the browser version of Teams.  Whiteboard is only available to the guest during the meeting and when they join from the guest tenant.

4 if a presenter in the meeting.

This table is available as a spreadsheet for filtering and with pretty icons too – download from the link below👇

I started out with https://docs.microsoft.com/en-us/microsoftteams/communicate-with-users-from-other-organizations which compares the features external users and guest users can use in Chat.  The table above is based on my testing of these features.  However I’ve included the original here as it stood when I wrote this article and I’ve expanded the footnotes to the table from that article here.

FeatureExternal access usersGuest access users
User can chat with someone in another companyYesYes
User can call someone in another companyYesYes
User can see if someone from another company is available for call or chatYesYes1
User can search for users across external tenantsYes2No
User can share filesNoYes
User can access Teams resourcesNoYes
User can be added to a group chatNoYes
User can be invited to a meetingYesYes
Additional users can be added to a chat with an external userNo3N/A
User is identified as an external partyYesYes
Presence is displayedYesYes
Out of office message is shownNoYes
Individual user can be blockedNoYes
@mentions are supportedYes4Yes
Make private callsYesYes
View the phone number for dial-in meeting participantsNo5Yes
Allow IP videoYesYes
Screen sharing modeYes4Yes
Allow meet nowNoYes
Edit sent messagesYes4Yes
Can delete sent messagesYes4Yes
Use Giphy in conversationYes4Yes
Use memes in conversationYes4Yes
Use stickers in conversationYes4Yes

1 Provided that the user has been added as a guest and is signed in as a guest to the guest tenant.
2 Only by email or chat address if a different address is used for Teams than email. (technically the chat address is the Session Initiation Protocol (SIP) address).
3 External (federated) chat is 1:1 only.
4 Supported for 1:1 chat for Teams Only to Teams Only users from two different organizations.  This refers to the “coexistance” setting which controls how Skype for Business Online (SfBO) and Teams work side by side in the same organisation.  As SfBO is retiring in July 2021 organisations are moving to Teams.  Once moved they work in ‘Teams Only’ coexistence mode and don’t use SfBO.
5 By default, external users in a meeting can’t see the phone numbers of any participant who have dialed-in. If you want to maintain the privacy of these phone numbers, select Tones for Entry/exit announcement type (this prevents the numbers from being read out by Teams). As a Teams Administrator to change these setting see Turn on or off entry and exit announcements for meetings in Microsoft Teams.

Now if you are a Teams Admin, you need a little more info on making sure things are set up how you need for your organisation.

When configuring Guest Users for Microsoft Teams refer to https://docs.microsoft.com/en-us/microsoftteams/guest-access-checklist to check you have configured all aspects of the behaviour you require.

You need to consider policies and settings for Teams to control guest/external access and features.  The sections in the Teams Admin Centre to look at are:

  • Meeting Policies – especially the Participants & Guests section
  • Meeting Settings – Anonymous meeting join permitted?
  • External Access
  • Guest Access

Below you will find the configuration used to write this guide for each of these.  As a consultant and trainer working with a wide range of organisations these are the settings that work for me and are basically ‘Everything On’.

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