Nets is a flexible and extensible network inventory and asset management system that works on all Unix and Windows platforms, and works with most SQL databases. Its complete GUI allows you to maintain details of your entire network, from network links down to interfaces and routers. It assists in provisioning, costing, reporting, and maintaining network details. It includes a network browser, an extension API, and plugins for IP address map visualisation, reports, schematics.
NetTraf consists of a daemon that gets information from a Linux interface and sends it on the network to NetTraf clients. Clients then can use the information to show to the user how the connection is performing. This program is mostly useful with dial-up connections on a masqueraded server, so all users on the network know when the connection is active, and if there is too much traffic on the line. This package DOES NOT comes with any client applications; you can find them on the homepage. The author needs help to develop a Linux client.
nsat is a fast, stable bulk security scanner designed to audit remote network services and check for versions, security problems, gather information about the servers and the machine, and much more. Unlike many other auditing tools, it can collect information about services independently of vulnerabilities, which makes it less dependent on frequent updates as new vulnerabilities are found.
Network Time Tools (NTT) is a set of network tools designed to provide monitoring of a network and the services on that network, and provide various reports on the hosts/services and optional alerts via email, pager, and cellphones. It comes with a protocol scanner, a bandwidth measurement tool, and a CGI front end that can handle a regular browser or WAP-enabled cellphones via WML.