Name        : libnids                      Relocations: (not relocatable)
Version     : 1.24                              Vendor: ALT Linux Team
Release     : alt3                          Build Date: Mon Apr 25 03:08:13 2011
Install date: (not installed)               Build Host: ldv-sisyphus.hasher.altlinux.org
Group       : Development/C                 Source RPM: (none)
Size        : 612466                           License: GPLv2+
Packager    : Dmitry V. Levin (for packages) <ldv@altlinux.org>
URL         : http://libnids.sourceforge.net
Summary     : Libnids is a library that provides a functionality of one of NIDS components
Description :
Libnids is a library that provides a functionality of one of NIDS
(Network Intrusion Detection System) components, namely E-component.
It means that libnids code watches all local network traffic, cooks
received datagrams a bit (quite a bit ;)), and provides convinient
information on them to analyzing modules of NIDS.  Libnids performs:
+ assembly of TCP segments into TCP streams;
+ IP defragmentation;
+ TCP port scan detection.
More technical info can be found in MISC file.

So, if you intend to develop a custom NIDS, you don't have to build
low-level network code.  If you decide to use libnids, you have got
E-component ready - you can focus on implementing other parts of NIDS.