IPNetwork is a set of utility classes for the .NET platform that take care of complex calculations related to networks, IP, netmask, CIDR, subnets, and supernets. It works with IPv4, has a light and clean API, and is fully unit tested.
Packet.Net is a .Net assembly that provides a way to dissect and construct network packets. Packet parameters are accessible via class properties.
A Java native serial library for Linux supporting CommAPI.
A toolkit of commonly used classes and functions, including Wordpress and Drupal SDKs.