What ports does Kaseya use?
The VSA by default uses ports 443 and 5721.
Port 443 is used for the Web Interface.
Port 5721 is used for Agent Check-in.
The Agent Check-in port can be set during the install, or afterwards on the System tab -> Configure page. Normally there is no need to change this value, but the default is TCP port 5721. SQL uses port 1433 by default.
The agent will only communicate outbound from the client to the server on the Agent Check-in port, there is no need to open inbound ports at the client side.
The server will be listening for agents on the Agent Check-in port, and for admins on the Web Interface port. So the server will need both these ports open inbound.
The admins will be accessing the web interface via their web browsers, so they will need to be able to make outbound connections on the web port.
If you are using KLC (Kaseya Live Connect) feature, you will also need UDP Port 5721 outbound open as the KLC connections use the UDP protocol in addition to the TCP protocol that the agents use. This is from the agents to the Kaseya server.
For the Agent Minimum Requirements and additional information please visit this help site.