Netwib is a network library providing : - network features : + address conversion + udp/tcp clients/servers + packet encoding/decoding/displaying + spoofing + sniffing + etc. - and general features : + data conversion + chained list, hash + portable threads + etc. Using all these functions, a network program can be quickly created. Netwib is available under the GNU GPL license. It was successfully installed under Linux, Windows, FreeBSD, NetBSD, OpenBSD, MacOS, Solaris and HP-UX. In order to provide new features, functions prototypes may vary between versions. So, a program created with version 5.1.0 might not compile with version 5.5.0. To move around this problem, several versions of netwib can be simultaneously installed on the same system. Netwib's features correspond to least common denominator of functions available on systems. This ensures a program compiled under one system will also compile on another. However, this design choice does not permit advanced features.