Heads up! There is a significant client side firewall change being implemented for the Microsoft Container Registry. On 3rd March, 2020, the data endpoint will change from*.cdn.mscr.io to *.data.microsoft.com. This issue only impacts customers with client firewall or VNet rules.
What will change? It’s the underlying data endpoint that will change. Once a change of the data endpoint is confirmed, clients can remove the *.cdn.mscr.io FQDN.
To access MCR, the following FQDNs are required:
| Protocol | Target FQDN | Available |
| https | mcr.microsoft.com | Now |
| https | *.cdn.mscr.io | Now – March 3, 2020 |
| https | *.data.mcr.microsoft.com | March 3, 2020 |
Note that docker pull commands will not change. For example, the following docker pull command will remain the same:
docker pull http://mcr.microsoft.com/windows/servercore
For more information, please see https://aka.ms/mcr/firewallrules