yes.

In the process of adding ECS, if the backend ECS has the firewall enabled, it is necessary to open the access rights to the intranet address of the load balancing instance. The load balancing instance transmits data and checks the health of the backend ECS through the intranet.

The private network address of load balancing is the address after the first IP address field is changed to 10. For example, if the public IP address is 172.172.172, the private IP address is 10.172.172.172.