The traffic direction of a firewall is based on the zone priority.

On Huawei firewalls, traffic direction is determined according to the priority of security zones . When traffic moves from a low-priority zone to a high-priority zone , that direction is called Inbound . For example, traffic going from the Untrust zone to the Trust zone is considered inbound because Untrust has a lower security priority than Trust.

By contrast, traffic moving from a high-priority zone to a low-priority zone is called Outbound . A common example is internal users in the Trust zone accessing resources on the Internet in the Untrust zone. This zone-priority concept is important because firewall security policies, packet filtering behavior, and session control are all evaluated according to the source zone and destination zone.

Understanding inbound and outbound directions is essential when configuring interzone security policies. Administrators must know whether traffic is flowing from low to high priority or high to low priority in order to apply the correct permit, deny, NAT, and inspection rules. Since the question specifically asks for the direction from a low-priority zone to a high-priority zone, the correct answer is Inbound .