Can disable client isolation based on the ip address?

Hi ，it seems you want to configure the 2 ONT communication each other in same VLAN ;
you can reference below :

Configuring VLAN-based Layer 2 User Bridging.
// create VLAN profile :
huawei(config)#vlan service-profile profile-id 3
huawei(config-vlan-srvprof-3)#user-bridging enable
huawei(config-vlan-srvprof-3)#commit
huawei(config-vlan-srvprof-3)#quit

//bind the VLAN profile to the VLAN (example vlan 300 is your service vlan):

huawei(config)#vlan bind service-profile 300 profile-id 3

Thanks for your reply. But what I meant is one client A connected to the ONT, and another device B is connected to the upstream core switch , this two devices are in the some vlan, Can we whitelist the device B to let the client A communicate with device B? Device A is connected to ONT, but Device B is connected to the core switch. Please advise, thanks.

we don't want to enable user-bridging (disable client isolation) for the whole VLAN, just need to whitelist some server IP addresses which are connected to the core switch. Please advise, thanks in advance.

I think it can be implemented, but not configured on the ONT. Instead, it is configured on the core switch.

You can try testing the ACL rules.

thanks for your reply. Can you please advise how to configure ACL on core switch? Need to disable client isolation first, then apply ACL on core switches?

Another question is when Device A is connected to ONT, and device B connected to core switch, then default can ping from device A to device B or both directions can ping each other?
We tested it cannot ping device A (ONT) from device B (core switch) when they are in same vlan and same subnet.

Sorry, we need to enable client isolation for whole VLAN ,but also need to whitelist some IP addresses. Some devices are connected to the core switch, and the client machines should be able to access them when they in same VLAN.
The post above maybe make you confused. sorry about that.

Hello Peter2019
please open another post，
This way more people will see and solve problems for you faster.
thanks