Active/Active high availability is a deployment mode that allows both firewalls in an HA pair to actively process traffic and share the load. Active/Active HA is suitable for environments that require real, full-time redundancy from both firewalls at all times, as there is no failover time or session loss in case of a firewall failure. Active/Active HA is also suitable for environments that require that both firewalls maintain their own routing tables for faster dynamic routing protocol convergence, as each firewall can run its own routing protocols and exchange routes with other routers independently. Active/Active HA is also suitable for environments that require that traffic be load-balanced across both firewalls to handle peak traffic spikes, as each firewall can process a portion of the traffic and increase the overall throughput and performance. Active/Active HA is not suitable for environments that require Layer 2 interfaces in the deployment, as Layer 2 interfaces are not supported in Active/Active HA mode. Active/Active HA is also not suitable for environments that require that all configuration must be fully synchronized between both members of the HA pair, as some configuration settings are not synchronized in Active/Active HA mode, such as virtual router configuration, virtual wire configuration, and QoS configuration. Reference: : https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/high-availability/set-up-activeactive-ha : https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/high-availability/set-up-activeactive-ha/determine-your-activeactive-use-case

https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/high-availability/configure-ha-clustering

An external zone is a type of zone that will allow different virtual systems to communicate with each other. An external zone is a special zone that is shared by all virtual systems on the firewall and can be used to route traffic between virtual systems without leaving the firewall. The external zone can also be used to route traffic to other zones within the same virtual system1. The other options are not correct. A tap zone is a type of zone that is used to passively monitor traffic without affecting the flow of packets2. A virtual wire zone is a type of zone that is used to create a transparent bridge between two network segments without changing the original IP addressing or routing3. A tunnel zone is a type of zone that is used to terminate VPN tunnels or other types of encapsulated traffic4. Reference: 1: https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/virtual-systems/communication-between-virtual-systems/inter-vsys-traffic-that-remains-within-the-firewall/external-zone 2: https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/networking/configure-interfaces/configure-a-tap-interface 3: https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/networking/configure-interfaces/configure-a-virtual-wire 4: https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/networking/configure-interfaces/configure-a-tunnel-interface

Make sure Panorama is running the same or a later PAN-OS version than you are upgrading to. You must upgrade Panorama and its Log Collectors to 10.2 before upgrading the managed firewalls to this version. In addition, when upgrading Log Collectors to 10.2, you must upgrade all Log Collectors at the same time due to changes in the logging infrastructure. https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-upgrade/upgrade-pan-os/upgrade-the-firewall-pan-os/upgrade-firewalls-using-panorama

https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/high-availability/set-up-activepassive-ha/configure-activepassive-ha