This documentation is for XNAT versions 1.6.0 - 1.6.5. You can find the latest documentation for XNAT 1.7 at https://xnat.org/documentation
There is no documentation, which there really should be. And there really should a GUI tool for managing those, but there’s not one of those either.
You can find the currently configured IPs on the whitelist by calling:
You can PUT to the same REST address to change the whitelisted IPs:
And that adds my IP to the IP whitelist.
The payload of IPs on the PUT can be separated by whitespace and/or commas.