Logging WAN interface into Captive portal

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[nineparsecs]

Hi community, i live in residences at a district hospital. We have a managed broadband service that you have an
account for, and log in via a portal web page.
Currently i am not able to use shares or NAS as none of my devices can see each other. Having used Endian in the
past, my idea is to segment off my devices using Endian. My question is, how can i log the WAN interface into the
portal web page?

Thank You for reading.