JDNS

JDNS is a software that allows for simple and flexible DNS implementation. It is capable of performing all types of DNS queries, including SRV, as well as Multicast DNS queries and advertising. The application is written in C and licensed under the MIT license. JDNS can be used with any application that supplies UDP sending/receiving functionality through callbacks. For Qt users, there are available wrappers and a command-line tool called ‘jdns’ for testing functionality.

The features of JDNS are extensive, including a DNS client "stub" resolver that can fetch any record type, with decoding available for known types such as A, AAAA, SRV, MX, TXT, etc. JDNS also supports retries, caching/expiration, and CNAME following. Multicast queries and advertising are supported, with the algorithm logic adapted from Q3Dns.

JDNS was created as a replacement for the Qt DNS implementation, which is being phased out in Qt 4. At the time of its creation, it was difficult to find a DNS library that met the necessary conditions for cross-platform friendliness, integration into existing eventloops, and sensible licensing.

Although JDNS has no dependencies, users must provide their own UDP support through callbacks and integrate JDNS into their existing event system. The Qt wrappers, while available, do depend on Qt. The latest source for JDNS can be found in the ‘iris/irisnet/jdns’ module of the Psi CVS.