Update outbound-rules-control-egress.md

Backlog work item 46980: Doc to improve - AKS needs Azure Storage service tag as it connects to md-XXXX.blob.storage.azure.net endpoint - firewall

Author: axelgMS

articles/aks/outbound-rules-control-egress.md

@@ -40,6 +40,8 @@ The following network and FQDN/application rules are required for an AKS cluster
 * AKS uses an admission controller to inject the FQDN as an environment variable to all deployments under kube-system and gatekeeper-system. This ensures all system communication between nodes and API server uses the API server FQDN and not the API server IP.
 * If you have an app or solution that needs to talk to the API server, you must add an **additional** network rule to allow **TCP communication to port 443 of your API server's IP**.
 * On rare occasions, if there's a maintenance operation, your API server IP might change. Planned maintenance operations that can change the API server IP are always communicated in advance.
+* Under certain circumstances, it might happen that traffic towards md-*.blob.storage.azure.net is required. This dependency is due to some internal mechanisms of Azure Managed Disks.
+
 
 ### Azure Global required network rules