Use an AXFR Transfer if you want to perform a direct zone transfer into the Constellix name servers from an external source name server.
1. In the sidebar menu click Managed DNS and then select Domains
2. Select the Domain Name you would like to transfer.
3. Click on the Import Records button
4. Select the Import Records from drop down menu and then select the option Name Server (AXFR).
5. In the text box, enter the IP address of the source name server that will perform the transfer. This source name server must be set up to allow transfers to the IP addresses listed on screen. If the Replace Existing Records check box is enabled, all existing records in the domain will be removed. Click Import.