PortPeeker is a freeware utility for capturing network traffic for TCP, UDP or ICMP protocols (see Note below about ICMP traffic). With Port Peeker you can see what traffic is being sent to a given port, easily and quickly.

PortPeeker is a single standalone exe will should work on Windows 95, 98, 98SE, ME, NT, 2000, XP and 2003 and can be placed anywhere on the system. We recommend creating a desktop shortcut to PortPeeker so its quick and easy to find and use.

NOTE on Windows NT, 2000, and XP you will not by default be able to listen to ICMP traffic. Windows NT and Win2000 have security in place that inhibits the use of ICMP. The work around for NT is to disable the security check on RAW sockets by creating the following registry variable and settings its value to DWORD 1: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Afd\Parameters\DisableRawSecurity

Once you have started PortPeeker you have to configure it as to what protocol and port (or just ICMP protocol as it doesn't use 'ports') to listen on. You can also configure PortPeeker as to what type of traffic events to record. For example if we want to listen for TCP port 80 traffic (http), we would configure PortPeeker to listen on TCP 80.