Merge pull request #77874 from iainfoulds/patch-4

[AKS] Add clarity on use of TCP port 9000

Author: PRMerger19

articles/aks/limit-egress-traffic.md

@@ -67,7 +67,7 @@ In AKS, there are two sets of ports and addresses:
 The following outbound ports / network rules are required for an AKS cluster:
 
 * TCP port *443*
-* TCP port *9000*
+* TCP port *9000* for the tunnel front pod to communicate with the tunnel end on the API server.
 
 The following FQDN / application rules are required: