Why is a new client being blocked immediately by CDR when it connects to the network?

Zyxel_Cooldia

Question:
Why is a new client being blocked immediately by CDR when it connects to the network?
Answer:
The firewall containment list references the client’s source IP.
New devices might obtain an IP address that is still in the containment list if the DHCP lease of a contained client expires before the containment period ends.
It is strongly recommended to configure the DHCP server leasing time greater than 2 times of containment period time.