TrinityOS is a step-by-step, example-driven HOWTO on building a very functional Linux box with strong security in mind. TrinityOS is well known for its strong packet firewall ruleset, Chrooted and Split DNS (v9 and v8), secured Sendmail (8.x), Linux PPTP, Serial consoles and Reverse TELNET, DHCPd, SSHd, UPSes, system performance tuning, the automated TrinityOS-Security implementation scripts, and much more.
RULI stands for Resolver User Layer Interface. It's a library built on top of an asynchronous DNS stub resolver. RULI provides an easy-to-use interface for querying DNS SRV resource records. The main goal is to promote wide deployment of SRV-cognizant programs. RULI aims to automatically perform all the SRV logic described by RFC 2782, and to comply with related specifications. As a side-effect, RULI also provides a general-purpose, event-driven, asynchronous, stub DNS resolver. There are bindings for Perl, PHP, Guile/Scheme, Java, and Lua. IPv6 is supported.
ZoneMaster is a tool for zone file and name server management. It consists of a library that can configure BIND and a Web-based user interface that is used to access the data that is stored in a database. A bootstrap script allows you to initialize the database with all necessary information retrieved from an existing configuration. All modifications are saved as jobs in the database, and a job handler makes the necessary changes from time to time. The user interface is based on XSLT-stylesheets and can be easily modified.
PowerDNS Backend Development Kit allows a developer to code backends which can be loaded at runtime by PowerDNS, a nameserver that reads data from different backends. The stock distribution comes with MySQL and PostgreSQL and other backends. It is also possible to do failover, loadbalancing, and geodirection from a backend.
PHPresolver is a DNS resolver library written in pure PHP. It may help you code email address validity verification under the Win32/BeOS port of PHP because the current version has no support for DNS-related functions such as getmxrr() or checkdnsrr(). In addition, the library partially supports IPv6 address resolution.
GNU Libidn is an implementation of the Stringprep, Punycode, and IDNA specifications defined by the IETF Internationalized Domain Names (IDN) working group. It is used to prepare internationalized strings (such as domain name labels, usernames, and passwords) in order to increase the likelihood that string input and string comparison work in ways that make sense for typical users throughout the world. The library contains a generic Stringprep implementation that does Unicode 3.2 NFKC normalization, mapping and prohibition of characters, and bidirectional character handling. Profiles for iSCSI, Kerberos 5, Nameprep, SASL, and XMPP are included. Punycode and ASCII Compatible Encoding (ACE) via IDNA are supported.
Poslib is a library which provides easy access to the Domain Name System. The client part can be used to create DNS client applications, while the server part lets you easily create a multi-threaded DNS server program, portable to many operating systems including Linux, FreeBSD, and Windows.
Whoisdomaincheckup is a Web-based (PHP) application that can check the registration status of a domain name. In particular, it can check whether a domain name is currently free for registration. It doesn't use any exec or system commands, but instead uses the fopen command to access the Whois servers.
dnspython is a DNS toolkit for Python. It supports almost all of the record types. It can be used for queries, zone transfers, and dynamic updates. It supports TSIG authenticated messages and EDNS0. dnspython provides both high and low level access to DNS. The high level classes perform queries for data of a given name, type, and class, and return an answer set. The low level classes allow direct manipulation of DNS zones, messages, names, and records.