Networking Tips Tricks

When troubleshooting client or server side application network connectivity issues, it is often necessary to determine if access to a certain port that the application uses is being blocked. In this article we’ll take a quick look at how to view open ports using a number of lightweight freeware tools for Microsoft Windows. You might just be surprised at how effective these free utilities are at helping you to scan open ports and get to the root of the problem. The first tool of note is one many admin and support folk might have heard of; the Windows command line utility called netstat.exe. Netstat.exe, located in the Windows ‘System32’ folder, allows you to view ports that are open or in use on a particular host, but should not be confused with a network port scanner which actually probes a host for open ports. To view which ports are listening (open) on a local host using netstat, from the command prompt type the following: netstat –an ¦find /i “listening” The results w...