A request to resolve an IP address is received by a Domain Name Server (DNS). A record, such as an MX record, relating to the request is obtained that comprises a unique label (e.g. record=customer-com.mail.messaging.com) that is used in determining how to resolve the request. The unique label portion of the record (e.g. customer-com) is used to identify information relating to the request such as a version of software/service to use to handle the request, a region used to handle the request, and the like. The same record may be used to direct a request to a different version and/or different region. For example, without changing the record, a request at one time may access a first version/region and a request at a different time access a different version/region.