PortQry tool

Portqry currently version 2 is one of free utility tools provided by Microsoft. You can use this tool in many ways to troubleshoot connectivity on network, Active Directory, Exchange …. The tool comes in 2 different flavors – GUI or command line — it is up to you what you prefer and how you want to use it.

Download link here

portqry -n 10.0.10.2 -p tcp -o 433,8080,3389 -l mylog.log

This command is run against host 10.0.10.2 and scans tcp ports 433,8080,3389 and once completed it will create a log file mylog.log with the result.

PortQry reports finding or status on TCP/IP ports in 3 ways:

ListeningA process is listening on the port on the computer that you selected. Portqry.exe received a response from the port.
Not ListeningNo process is listening on the target port on the target system. Portqry.exe received an Internet Control Message Protocol (ICMP) “Destination Unreachable – Port Unreachable” message back from the target UDP port. Or if the target port is a TCP port, Portqry received a TCP acknowledgement packet with the Reset flag set.
FilteredThe port on the computer that you selected is being filtered. Portqry.exe did not receive a response from the port. A process may or may not be listening on the port. By default, TCP ports are queried three times, and UDP ports are queried one time before a report indicates that the port is filtered.

Some tips how to use this tool:

  1. Troubleshoot Active Directory connectivity issues KB310456
  2. Troubleshoot Microsoft Exchange Server connectivity issues KB310298
  3. More on usage and different switches with PortQry – here