Office Support / Office 365 Admin

Let Skype for Business Online users communicate with external Skype for Business or Skype contacts

Thumbnail and link to video: Link Online Extetrnal Communications

Important   Office 365 organizations that have signed up before 7/24/2015 will need to allow external access and then add the right allowed domains. Organizations that have signed up after 7/24/2015 will just need to add the domains to the allowed list. External access is allowed by default.

You can let people add Skype for Business or Skype users outside your organization to their list of Skype for Business contacts. Go to the Office 365 admin center > Skype for Business > Organization > External communications.

Tip    For a customized list of setup tasks, see Guided walkthrough: Set up Skype for Business external communications.

Settings for On except for blocked domains:

Turn on external communications and public IM connectivity

Settings for On only for allowed domains:

External communication setting - only allowed domains

Note   Connectivity with instant messaging providers other than Skype is not available.

Set up communication with external Skype for Business users

  1. Verify your Domain Name Server (DNS) settings for external communications.

  2. Sign in to Office 365 and go to theOffice 365 admin center > Skype for Business > Organization > External communications.

  3. Under External access, choose On except for blocked domains


Choose On only for allowed domains, and then add the name of the organization you want to communicate with under Blocked or allowed domains.

Keep in mind:

  • The organization you’re communicating with must also allow communication with your domain. If the other organization has Lync or Skype for Business Server on premises, refer them to the TechNet article Configuring Federation Support for a Lync Online Customer.

  • When you’re communicating with someone in a federated domain, you can only use Skype for Business features (for example, video conversations or desktop sharing) that are turned on in both organizations.

  • If the external access setting is changed from “On only for allowed domain” to “On except for blocked domain”, the domains that are listed won’t be kept.

Set up communication with Skype users

  1. If you haven’t already done so, verify your DNS settings for external communications.

  2. Click Organization > External communications.

  3. Select the check box under Public IM connectivity, and then click Save.

Available with Skype* users

Not available with Skype* users

  • Presence

  • Person-to-person instant messaging

  • Person-to-person audio calls

  • Video conversations

  • Find and add Skype for Business contacts in Skype

  • IM or audio conversations with three or more people

  • Desktop and program sharing

Note   Skype users signed in with their Microsoft account (formerly Windows Live ID).

Notify your users

Once you’ve set up external communications and verified that it works, let your users know what features are available. You can also direct them to these help topics:

Verify DNS settings for external communications

  1. Sign in to Office 365 and go to theOffice 365 admin center > click Domains.

  2. Select your custom domain name, and then click Troubleshooting.

    Verify your custom domain by clicking Troubleshoot on the domains page

  3. If necessary, update your DNS records as appropriate.

Applies To: Office 365 Admin, Skype for Business Online admin center, Skype for Business, Skype for Business Online

Was this information helpful?

Yes No

How can we improve it?

255 characters remaining

To protect your privacy, please do not include contact information in your feedback. Review our privacy policy.

Thank you for your feedback!

Change language