Sure, if they can connect to each other throughout the networks and firewalls, this will work just fine :)

Do i need to portforward the default port of cluster probe?

Correct, it's the port 23570 (TCP). Please make sure that no software/hardware firewall is blocking communication.

In setup > system administration > cluster (Under IPs/DNS Names used for Connections Between Nodes) Will I put the public IP address with port 23570 in the cluster node setup?

That's populated automatically after the cluster setup :) Please have a look at our cluster setup step-by-step tutorial to complete the cluster configuration without much trouble :)

Hi sir, I already set up a clustering on a different location and the Cluster status is fine. But I noticed that after i moved my groups into my cluster probe, the cluster pc contains only the probe device and my group did not show in failover. I also noticed that they were connected but the failover node is not receiving any data. Btw I'm using a ping sensor.

Check the link for references

http://postimg.org/image/4g51njmpv/

http://postimg.org/image/a5la7usw3/

It might take a while until the configurations are in sync. Can you upload a picture of your current device overview?

Here, it seems ok now. But as you can see in the image below the failover node cannot monitor several sensors. Is the failover node need to connect through VPN?

http://postimg.org/image/sfwe3yxl1/

I set up a VPN to the failover node and now the sensors are now ok. Thanks