Hello friends, in Day 5 of my Palo Alto VM-Series deployment on Azure cloud, I focused on the core Azure networking terms you must understand before we go deeper into traffic flow and lab topology. In this video I explained Virtual Network and Subnet basics, and why subnet planning matters when you build your infra in Azure. I also shared a key Azure-specific point: in a /24 subnet you don’t get the full 254 usable IPs like traditional networking—Azure reserves IPs (like .1 for gateway and .2/.3 for DNS), so you effectively get fewer usable addresses (example: 251 usable). This is very important when you design your lab or production setup. Then I moved into routing concepts that directly impact how your firewall deployment will work. I explained System Routes (automatic routes injected by Azure) and why you can’t force a custom path using only system routes. After that, I covered UDR (User Defined Routes), where I manually force traffic—like web subnet to SQL subnet—to go via my firewall first, so the firewall can inspect and allow/deny the traffic. Finally, I explained NSG (Network Security Group) as a rule set you can apply at subnet or VM level to control what ports/protocols are allowed (for example, allowing only HTTP/HTTPS from internet). This video is the base for the upcoming topology and traffic-flow labs.