Hi,
As you mentioned, ThousandEyes is a cloud-based solution.
So internet access is required, it is not an optional one.
And, the basic requirements for Enterprise Agents are:
- DNS resolvers for domain resolution
- NTP for time synchronization
- TCP 443 outbound access —which also allows for proxy configuration for agent use, if required for internet
access.
You can find more detailed steps for activating ThousandEyes on Catalyst 9000 series in the below link:
Cisco ThousandEyes Activation Guide
https://www.cisco.com/c/dam/m/en_us/customer-experience/collateral/thousandeyes-activation-guide.pdf
Thanks,
Johnson