Test Agent interface metadata configuration

The Interfaces (metadata) tab of the Test Agent configuration dialog lets you configure an external IP address for a Test Agent interface.

This allows a Test Agent to act as a server in measurements even if it is behind a NAT router. (The party initiating the measurement is termed “client”, whereas the other party is called “server”.) Other Test Agents will then use the public address of the router for communicating with the server Test Agent behind NAT. A prerequisite for this to work is that the necessary port forwarding has been set up between the NAT router and the server Test Agent. The port forwarding setup needs to be handled outside Paragon Active Assurance, and the details are not dealt with here.

For a Test Agent that is not behind NAT, this setting is not applicable. Consequently, you need to use this setting only if both client and server are behind NAT (otherwise, simply pick the Test Agent that is behind NAT to act as client).

An example of port forwarding and use of an external IP address is shown in the diagram below. In this example, UDP is tested on port 5000. Other tasks may use different ports.

../../_images/port-forwarding.png

An external IP address can be set for both IPv4 and IPv6. In each case, the address assignment can be either automatic or manual.

  • Automatic: The IP address used by the management interface when connecting to Control Center will be assigned as external IP address. This option can only be used for the management interface.

  • Manual: Here you enter an external IP address manually in the External IP field.

Once configured, the external IP address will appear as a separate interface item when configuring tasks and monitors, with “(external)” as postfix.

Note

The automatic address assignment only works for the IP version currently in use on the management interface. For example, if management (on eth0) is currently done over IPv4, and you set External IPv6 address to Automatic on eth0, the address assignment will fail if you try to run some task over IPv6 on eth0. The workaround is to set an IPv6 address manually for the eth0 interface.

Note on defunct “Use public address” option

Previous versions of Paragon Active Assurance (Netrounds) had an option Use public address in the Test Agent interface configuration dialog (Interfaces tab > IPv4 address tab). Selecting this option was largely equivalent to configuring an external IP address as “Automatic” on the management interface in the current version. However, the old and new features differ in the following ways:

  • The new feature works for both Test Agent Appliance and Test Agent Application, while the old one was restricted to the Appliance.

  • The new feature is (independently) applicable to all interfaces, whereas the old one was limited to the management interface.

  • The new feature allows you to choose between private and external IP address for each measurement task, unlike the old feature which applied globally to anything the interface was used for.

  • The new feature allows you to manually specify an external IP address, an option which was previously absent.

  • The new feature applies to both IPv4 and IPv6, while the old one was for IPv4 only.