If you want a quick and easy way to check SQL Server connectivity, without resorting to the full blown functionality of WireShark (or similiar), you can use Microsoft’s PortQryUI utility to troubleshoot TCP/IP connectivity problems. PortQryUI is a GUI on top of the PortQry command line tool, with predefined groups of ports to scan. One of the these groups targets SQL Server, which consists of UDP port 1434 and TCP port 1433. To check these ports, enter the IP address (or fully qualified domain name) of the target SQL Server instance, select SQL Service in the ‘Service to Query’ drop-down box and click the Query button.
If the ports are OK, the utility will list the ports as Listening. Otherwise, it will tell you the ports are being Filtered or are Not Listening.
You can download PortQryUI from here: PortQryUI – User Interface for the PortQry Command Line Port Scanner.