PortPeeker is a standalone port listener, which uses whatever TCP/UDP port you specify and logs all incoming requests in detail. It provides a simple searchable text log overview of all connections that have taken place, as well as their details. In addition, a handy drop-down box on top lists all the IP addresses that have connected, and selecting on will let you jump to the associate log entries. PortPeeker can even send a user defined response to connection requests or data in events or simply echo the data back. Useful for application testing (errors can be logged as well) and security monitoring for vulnerable ports.