What is the option "Remove Listening Port when VS down" on Avi UI?

Answer

The option Remove Listening Port when VS down is available on Avi user interface. By enabling this option for a virtual service (VS) in down state, the listening ports on Avi Vantage for the virtual service are removed, the virtual service, therefore will not respond even to incoming TCP requests for the configured ports.

By default, the Remove Listening Port when VS down option is not enabled for a virtual service. When this option is not enabled for a virtual service, Avi Vantage will accept TCP connections for the virtual service in down state. Avi Vantage responds to telnet requests for the virtual IP (VIP) and the configured port number, even though the virtual service is in down state.

To enable Remove Listening Port when VS down, navigate to Applications>Virtual Services, and click on the edit icon at the top right.

selecting virtual service

Navigate to Advanced, and select the checkbox for Remove Listening Port when VS down, which is available under Other Settings. Click Save.

remove listening port option

Use Cases

Remove Listening Port when VS down option helps an admin or a user to decide if the virtual service is in up state or down state. Once this option is enabled for a virtual service, the virtual service in down state will not respond to TCP or telnet requests. After enabling this option, try the telnet command for the virtual service (in down state) and the virual service will not respond to the telnet request, as seen in the below screenshot.

In the example shown below, 10.10.1.200 is the IP of a virtual service in down state. The telnet request for IP 10.10.1.200 and port 80 fails as Remove Listening Port when VS down is enabled for the virtual service.


C:\Users\avi>telnet 10.10.1.200 80
Connecting To 10.10.1.200...Could not open connection to the host, on port 80: Connect failed