Reflective ACL configuration on S series switch.
On an S series switch, except S1700:
Reflective ACL is a type of dynamic ACL. It controls user access according to the upper-layer session information in IP packets to prevent hosts on the public network from connecting to the private network unless users on the private network connect to the public network first. In this way, the reflective ACL protects the private network of an enterprise against attacks from unauthorized external users.
For example, GE2/0/1 on a switch connects to the Internet. The reflective ACL is configured on GE 2/0/1 in the outbound direction to prevent the server on the Internet from accessing hosts on the internal network unless the internal hosts access the server first. The configurations are as follows:
[HUAWEI] acl 3000
[HUAWEI-acl-adv-3000] rule permit udp
[HUAWEI] interface gigabitethernet 2/0/1
[HUAWEI-GigabitEthernet2/0/1] traffic-reflect outbound acl 3000 timeout 600 //Configure reflective ACL on GE2/0/1 to match UDP packets and set the aging time.
[HUAWEI] traffic-reflect timeout 900 //Set the global aging time for reflective ACL.
Run the display traffic-reflect command in the system view to view the reflective ACL information.