I don't know that ConenctionProperty is actually database functionality . function. it's server functionality related to the connection, right?
this works in SQL2008 and above, and I just checked, and it doesn't get affected by compatibility level either:
SELECT
ConnectionProperty('net_transport') AS 'net_transport',
ConnectionProperty('protocol_type') AS 'protocol_type',
ConnectionProperty('auth_scheme') AS 'auth_scheme',
ConnectionProperty('local_net_address') AS 'local_net_address',
ConnectionProperty('local_tcp_port') AS 'local_tcp_port',
ConnectionProperty('client_net_address') AS 'client_net_address',
ConnectionProperty('physical_net_transport') AS 'physical_net_transport'
Lowell