I need to know if someone is on-site at organization or off-site. I am trying to figure out if I can tell this by the IP address or if there is another way for me to know this. User story: Library resources are authenticated by publishers using IP auth. We want to use a third party dedicated proxies because publishers can’t use Zscaler IPs. We need the third party to know if a user is accessing from on-site or off-site for reporting purposes. We want to limit the number of off-site users and allow for an unlimited number of on-site users.
But this only tells you if the access to the library ressource happened using ZScaler. Whether that request is coming from an on-prem user or one of your remote users is a different story; depends on your exact configs (network routing, GRE/IPSec tunnel setups, pac files, etc.)