Following are the limitations for Proxy configuration for web based datasources like SOAP, WSDL, REST, XML/HTTP:

1. TDV only supports http/https basic authentication for proxy setting and not for Kerberos.

2. Passthrough with proxy server is not supported.

3. Proxy authentication is not supported as a per-datasource basis. Username or Password need to be set in /Server/Configuration/Network/Proxy Settings.