Archived - Apple Remote Desktop: Connecting through a firewall, NAT or VPN
If you are planning to use Apple Remote Desktop through an external firewall, NAT (Network Address Translation) system or VPN (Virtual Private Network) connection, you may need to perform additional configuration steps to make sure that Apple Remote Desktop traffic is able to traverse the network.
When using an external firewall
Be sure that the proper ports are open to allow Apple Remote Desktop packets to pass through the firewall. For a list of ports, refer to the Admin Guide for your version of Apple Remote Desktop, or this article.
When using NAT
Similarly, if you wish to access a single client computer that is behind a NAT router, you need to set the router to forward the proper ports to the client computer you wish to access. For a list of ports, refer to the Admin Guide for your version of Apple Remote Desktop, or this article.
When making any type of connection through NAT, it is usually only possible to direct (port map) a particular type of traffic to a single IP address on your private network. This means you may only be able to control a single NAT client when using Remote Desktop from a public IP address.
When using VPN
When using VPN, you may need to set your router to allow a larger MTU and/or to disallow fragmented packets. For details, refer to the Admin Guide for your version of Apple Remote Desktop.