Manage external access
With Microsoft Teams external access—also known as federation—Teams users from other domains can participate in your chats and calls. You can also allow other external users who are still using Skype for Business Online, Skype for Business on-prem, or even Skype, to participate. Unlike users granted guest access, users who are granted external access have no access to the inviting organization's teams or team resources. They can only participate in one-on-one federated chat. Tenant administrators choose between the two communication options depending on which level of collaboration is desirable with the external party.
When to use external access (federation)
Consider using external access when:
- You have users in different domains in your business.
- You want the people in your organization to use Teams to contact people in specific businesses outside of your organization.
- You want any Teams user worldwide to find and contact you, using your email address.
Configure external access in Teams admin center
You can easily set up external access for your organization by using the Teams Admin center. There are three scenarios for setting it up:
- Scenario 1. You can use Open Federation. This is the default setting, and it lets people in your organization find, call, send IM/Chats, and set up meetings with people external to your organization. When you use this setup, your users can communicate with all external domains that are running Teams or Skype for Business and are using Open Federation or have added your domain to the Allow list.
- Scenario 2. You can add a domain or domains to the Allow list. It's important to know that if you do this it will Block all other domains.
- Scenario 3. You can add a domain or domains to the Block list. If you do this it will Allow all other domains.
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