Azure point-to-site VPN: the rollout checklist
Bring clients, identity, address ranges, and private DNS together in one testable access plan.
Read the guideClouds VPN Lab / Topic
DNS
Check the name, returned address, port, and application in that order.
Private applications need names as well as network paths. Use this collection to think through resolver reachability, private answers, and behavior after disconnect. Test name resolution separately from destination connectivity so a DNS problem does not lead to unnecessary changes in unrelated firewall or access rules.
Guides on dns
1 article in this collection.