Simple Packet Sender (SPS) is a Linux packet crafting tool. It supports IPv4, IPv6 including extension headers, and tunneling IPv6 over IPv4. It does not require pcap. It features packet crafting and sending one, multiple, or flooding IPv4 and IPv6 packets of type TCP, ICMP, or UDP (or cycling through all three). All values within an Ethernet frame can be modified arbitrarily. It supports IPv4 header options, TCP header options, and TCP, ICMP, and UDP data as well, input from either a keyboard as UTF-8/ASCII, a keyboard as hexadecimal, or from a file. IPv6 support includes hop-by-hop, "first" and "last" destination, routing, authentication, and encapsulating security payload (ESP) extension headers. For those without access to a native IPv6 network, IPv6 packets can be transmitted over IPv4 (6to4). Packet fragmentation is available for IPv4, IPv6, and 6to4. The assumed maximum transmission unit (MTU) can be changed if unusual fragment sizes are needed. IP addresses and port numbers can be randomized.
LibreNMS is an autodiscovering PHP/MySQL-based network monitoring system forked from Observium. It aims to be easy to use and painless to deploy, and to support monitoring of a wide range of devices. Observium's license changed to a modified QPL license in May 2012, then was split into free and commercial versions. The aim of LibreNMS is to continue to create a usable NMS, but with a community focus and GPL licensing.
BGPHist is a tool that receives MP-BGP updates, decodes them, and writes them to a database for logging and monitoring purposes. It supports not only Internet routes, but also IPv4 VPN, IPV6 VPN, and L2VPN. It sounds text output, MySQL databases, and Oracle databases. For the MySQL backend, there is also a simple PHP frontend. It could be used to monitor and log an ISP's customer activity for Internet and VPNs, as a passive BGP looking glass, or as a backend for some external monitoring and accounting system.
Sanewall is a firewall builder for Linux that uses an elegant language abstracted to just the right level. This makes it powerful and easy to use, audit, and understand. It allows you to create very readable configurations even for complex stateful firewalls. Sanewall can be used for almost any purpose, including control of any number of internal/external/virtual interfaces, control of any combination of routed traffic, setting up DMZ routers and servers, all kinds of NAT, providing strong protection (flooding, spoofing, etc.), transparent caches, source MAC verification, blacklists, and whitelists. Newer versions abstract the differences between IPv4 and IPv6, allowing you to define a common set of rules for both, while permitting specific rules for each as you need. Sanewall is a fork of FireHOL and can make use of existing FireHOL configurations.
xllmnrd is an IPv6 LLMNR responder daemon (primarily for GNU/Linux operating systems). It allows Microsoft Windows clients to get the IPv6 address of a server on the same local network without any DNS configuration and effectively complements IPv4-only NetBIOS name resolution provided by Samba.