ConceptDraw NetDiagrammer has been developed for professional computer network diagramming, LAN scanning and visualization, preparation of network documentation, and office/building/home network planning. It is intended for network administrators, IT directors, network designers and engineers, and for everyone who finds detailed network documentation, diagramming, and schematics critical. It includes large collections of task-specific shapes of network objects, as well as templates, samples, and easy-to-use wizards. It also allows drawing all types of UML diagrams, floor plans and office layout drawings, flowcharts and dataflow diagrams, workflows, and more.
Hunny Mail++ is a cross-platform C++ library that provides classes for SMTP, POP3, IMAP4, and NNTP clients. This mature toolkit, which has been in active development since 1997, offers many features, including support for TLS (SSL) and the most popular SASL authentication mechanisms, IMAP extensions, and NNTP extensions. The toolkit comes with well-written documentation and numerous example programs, making it easy to use.
FreeBSDShield is a DShield.org reporting client for FreeBSD and the ipfw firewall. It allows you to report attempted security breaches to the DShield cooperative firewall logging effort, which in turn helps the Internet Storm Center (and netizens at large) track trends in network security and catch emerging vulnerabilities.