There are a couple of protocols that can be used for connecting to a SQL server. Shared memory, TCP/IP, Named pipes, VIA namely. To find what protocol is used for a connection use the script: SELECT net_transport FROM sys.dm_exec_connections WHERE session_id = @@SPID; Replace @@SPID with another spid to check that connection. When on the local SQL server, the shared memory protocol is used if it is enabled, but this can be disabled to troubleshoot the other protocols. To see all the connections and the protocols currently being used, use: SELECT session_id,net_transport FROM sys.dm_exec_connections.