sysinternals

PsPing is a command-line utility for measuring network performance. In addition to standard ICMP ping functionality, it can report the latency of connecting to TCP ports, the latency of TCP and UDP round-trip communication between systems, and the TCP or UDP bandwidth available...

TCPView is a Windows program that will show you detailed listings of all TCP and UDP endpoints on your system, including the local and remote addresses and state of TCP connections.