Yes, most fax services provided by GreenLink are delivered with a new DID except for the "Inbound Fax to Email" service. This is because at least one extension is needed to be added to the login credentials of the Customer Portal to be able to access the fax area and manage faxing.
Customers can also have their existing fax DID ported over to GreenLink. The process often takes from 7-30 business days.
To learn more about what porting implies you can follow the link below: