In some deployments NAT may be required to reach the test agent.

For tests to work properly the peer node must communicate with the reachable IP address.

• Tests only working in one direction
• Test packets reaching peer with source address that does not exist directly on the source test agent

In Control Center, configure the interface(metadata) to add the ability to select the NAT IP address

Each test/monitor must be configured to use the metadata IP address instead of the interface.

https://app.netrounds.com/static/4.4.1.12/support/testagents/config-gui/ta-interface-metadata-config.html