Duo For Windows Logon - Authorized Networks

I am trying to setup a Whitelist of IP addresses so users are not prompted for Duo when on the Corporate LAN.

However, I have noticed that looking at the logs, the IP address that is reported back is

Does anyone have any idea what causes this?

[quote=“Icebun, post:1, topic:7553”]
[/quote] Check article help.duo.com/s/article/2302?language=en_US