How to access an APIPA address from another network?

[psychofaktory]

Hello,

I have a modem from my provider that has an administration interface with a web interface with which the DSL status and some line values can be viewed.

However, the device can only be accessed via the fixed address https://169.254.2.1.

The modem is connected to the OPNsense in an own subnet.

Now I would like to be able to access the modem's web interface from other networks.
How can I achieve this?

[lilsense]

allow the port forwarding and firewall to access the WAN port, then create a static route to the 169.254 network.