Disable hybrid to complete migration to the cloud
After you have moved all users from on-premises to the cloud, you can decommission the on-premises Skype for Business deployment. Aside from removing any hardware, a critical step is to logically separate that on-premises deployment from Office 365 by disabling hybrid. Disabling hybrid consists of 3 steps:
- Update DNS records to point to Office 365.
- Disable split domain in the Office 365 tenant.
- Disable ability in on-prem to communicate with Office 365.
These steps should be done together as a unit. Details are provided below.
In rare cases, changing DNS from pointing on premises to Office 365 for your organization may cause federation with some other organizations to stop working until that other organization updates their federation configuration:
- Any federated organizations that are using the older Direct Federation model (also known as Allowed Partner Server) will need to update their allowed domain entries for their organization to remove the proxy FQDN. This legacy federation model is not based on DNS SRV records, so such a configuration will become out of date once your organization moves to the cloud.
- Any federated organization that does not have an enabled hosting provider for sipfed.online.lync.com will need to update their configuration to enable that. This situation is only possible if the federated organization is purely on premises and has never federated with any hybrid or online tenant. In such a case, federation with these organizations will not work until they enable their hosting provider.
Update DNS to point to Office 365. The organization’s external DNS for the on-premises organization needs to be updated so that Skype for Business records point to Office 365 instead of the on-premises deployment. Specifically:
Record type Name TTL Value SRV _sipfederationtls._tcp 3600 100 1 5061 sipfed.online.lync.com SRV _sip._tls 3600 100 1 443 sipdir.online.lync.com CNAME lyncdiscover 3600 webdir.online.lync.com CNAME sip 3600 sipdir.online.lync.com CNAME meet 3600 webdir.online.lync.com CNAME dialin 3600 webdir.online.lync.com
Disable shared SIP address space in Office 365 tenant. The command below needs to be done from a Skype for Business Online PowerShell window.
Set-CsTenantFederationConfiguration -SharedSipAddressSpace $false
Disable ability in on-prem to communicate with Office 365.
The command below needs to be done from an on-premises PowerShell window. If you have previously imported a Skype for Business Online session, start a new Skype for Business PowerShell session.
Get-CsHostingProvider|Set-CsHostingProvider -Enabled $false