Connecting System Manager to a remote AHM unit over the Internet
Posted by Nicola Beretta on 21 January 2021 03:53 PM

In some circumstances it may be useful to connect to an AHM processor over a WAN connection or the Internet. This can be useful for remote assistance, training or troubleshooting.

AHM System Manager uses port 51321 TCP for control data, and ports 51324+ UDP (one for each connection) for metering data. These should be forwarded by your NAT to the IP address of the AHM unit.  By default this is

These ports cannot be changed, therefore via this method only one AHM unit can be connected to at a time. To connect to multiple AHM units you first need to ensure that each unit has its own IP address, then you can either use the VPN method as referenced later in this article or by multiple NAT rules setup un-enabled for each unit, then only enabling the rule for the unit you need to connect to.

We strongly recommend using a secure VPN to access the local network that the AHM is connected to. This isn't something covered in depth by this article, but guides on how to do this are easily found on the Internet.

AHM-64 was designed as a stand alone unit. Its Linux operating system is not installed with any antivirus or firewall. You should take steps to protect it with devices between the unit and the Internet, such as a good quality firewall and NAT to block ports when not in use.

Connections with System Manager using either method will take significantly longer than direct connections.