https://docs.microsoft.com/en-us/azure/network-watcher/network-watcher-packet-capture-overview

https://learn.microsoft.com/en-us/azure/network-watcher/network-watcher-ip-flow-verify-overview IP flow verify checks if a packet is allowed or denied to or from a virtual machine. The information consists of direction, protocol, local IP, remote IP, local port, and a remote port. If the packet is denied by a security group, the name of the rule that denied the packet is returned. While any source or destination IP can be chosen, IP flow verify helps administrators quickly diagnose connectivity issues from or to the internet and from or to the on-premises environment.

Reference:
https://docs.microsoft.com/en-us/azure/dns/private-dns-overview
https://docs.microsoft.com/en-us/azure/virtual-network/virtual-networks-name-resolution-for-vms-and-role-instances