Hi Daniel,
Thanks for reaching out to Adobe Community.
You can submit a request to client care to filter IPs. There are 2 options: admin access to block people on those IP addresses from logging into Classic, and report filters to block those IP addresses from getting counted in reports (they still see test content though) to block them from seeing test content. You can use a profile script to block people from a certain IP range
Note that the report filters will work in both Classic and Target Standard but the admin filters will only work in Classic. To block users from logging into Target Standard, choose the appropriate identity option: https://helpx.adobe.com/enterprise/help/identity.html#Adobe-supported%20identity%20types
Hope this helps!