Dnsmasq is a lightweight, easy to configure DNS forwarder and DHCP server. It is designed to provide DNS and (optionally) DHCP to a small network. It can serve the names of local machines which are not in the global DNS. The DHCP server integrates with the DNS server and allows machines with DHCP-allocated addresses to appear in the DNS with names configured either in each host or in a central configuration file. Dnsmasq supports static and dynamic DHCP leases and BOOTP/TFTP for network booting of diskless machines.
cqueues is a comprehensive event and networking library for Lua 5.2 and LuaJIT using modern Unix O(1) polling facilities. It includes libraries for buffered socket I/O, SSL/TLS sockets, DNS querying, signal handling, threading, file change notification, and X.509 key management. It natively supports Linux, *BSD, OS X, and Solaris systems without third-party dependencies, and is interoperable with any event loop that accepts plain descriptors, or is usable standalone.
dnscrypt-proxy acts as a DNS proxy between a regular client, like a DNS cache or an operating system stub resolver, and a DNSCrypt-aware resolver, like OpenDNS. The DNSCrypt protocol focuses on securing communications between a client and its first-level resolver. While not providing end-to-end security, it protects the local network (which is often the weakest link in the chain) against man-in-the-middle attacks. It also provides some confidentiality to DNS queries.
SendIP is a command-line tool to send arbitrary IP packets. It has a large number of options to specify the content of every header of a RIP, RIPng, BGP, TCP, UDP, ICMP, or raw IPv4/IPv6 packet. It also allows any data to be added to the packet. Checksums can be calculated automatically, but if you wish to send out wrong checksums, that is supported too.
NicTool is a DNS management suite with support for various DNS servers (djbdns, BIND, PowerDNS), SQL data storage, DNS entry parsing (RFC 1034 & 1035 compliance), tiered and delegated permissions so you can safely grant access to clients and admins, giving them only the permissions they need. Humans interact via the Web interface, and an API is used for scripting mass updates, DNS templates, provisioning, and more. All changes are logged to easily track change history and see who changed what, and when.
UpdateDD is a command line tool that updates a dynamic DNS record. It supports the following features: Web-based IP-detection, IP address caching, configuration files with C-like syntax, simple interface for managing multiple accounts and hostnames, and status output to syslog. Supported services include: changeip.com, dyndns.org, eurodyndns.org, ovh.net, no-ip.org, ods.org, hn.org, regfish.com, and tzo.com.