MaraDNS: An overview
MaraDNS is a small and lightweight cross-platform open-source DNS server.
The server is remarkably easy to configure for someone comfortable editing
text configuration files. MaraDNS is released under a BSD license.
Table of contents
What is DNS
The internet uses numbers, not names, to find computers. DNS is
the internet's directory service: It takes a name, like "www.maradns.org",
and converts that name in to an "IP" number that your computer can
use to connect to www.maradns.org.
DNS is one of these things many take for granted that is essential to
using today's internet. Without DNS, the internet breaks. It is critical
that a DNS server keeps the internet working in a secure and stable
MaraDNS was started in 2001 in response to concerns
that there were only
two freely available DNS servers (BIND and DjbDNS) at the time. MaraDNS
1.0 was released in mid-2002, MaraDNS 1.2 was released in late 2005, and
MaraDNS 2.0 was released in the fall of 2010.
MaraDNS 1.0 used a recursive DNS server that was implemented rather
quickly and had difficult-to-maintain code. This code was completely
rewritten for the MaraDNS 2.0 release, which now uses a separate recursive
MaraDNS was fully maintained and actively developed without needing
contributions from 2001 until 2010. MaraDNS 2.0 is the final release
that will be made without significant financial support being made.
Security and other critical bugs are still taken care of, but there
is no guarantee of any technical support above and beyond that.
MaraDNS 2.0 consists of two primary components: A UDP-only authoritative
DNS server for hosting domains, and a UDP and TCP-capable recursive
DNS server for finding domains on the internet. MaraDNS' recursive
DNS server is called Deadwood, and it shares no code with MaraDNS'
authoritative DNS server.
In more detail: MaraDNS has one daemon, the authoritative daemon (called
"maradns"), that provides information to recursive DNS servers
on the internet, and another daemon, the recursive daemon (called
"Deadwood"), that gets DNS information from the internet for web browsers
and other internet clients.
A simplified way to look at it: MaraDNS puts your web page on the Internet;
Deadwood looks for web pages on the Internet.
Deadwood has its own webpage
and release schedule. When new MaraDNS releases are made, they bundle
the current stable version of Deadwood in the source code tree; the
build scripts compile both MaraDNS and Deadwood at the same time.
Since MaraDNS' authoritative daemon does not support TCP, MaraDNS includes
a separate DNS-over-TCP server called "zoneserver" that supports both
standard DNS-over-TCP and DNS zone transfers.
Neither MaraDNS nor the UNIX version of Deadwood
have support for daemonization; this is handled
by a separate program included with MaraDNS called Duende.
Deadwood's Windows port, on the other hand, includes support for running as a
MaraDNS also includes a simple DNS querying tool called "askmara"
and a number of other miscellaneous tools: Scripts for processing
MaraDNS' documentation, a simple webpage password generator, some
Unicode conversion utilities, scripts for building and installing
MaraDNS, automated SQA tests, etc.
MaraDNS is a native UNIX program with a partial Windows port. Deadwood,
MaraDNS' recursive resolver, is a fully cross-platform application
with a full Windows port.
MaraDNS 2.0 has full (albeit not fully tested) IPv6 support.
MaraDNS 2.0's authoritative server uses code going all the way back
to 2001. The core DNS-over-UDP server has a number of components,
including two different zone file parsers, a mararc parser, a secure
random number generator, and so on.
MaraDNS is written entirely in C. No objective C nor C++ classes are
used in MaraDNS' code.
MaraDNS 2.0's "Deadwood" recursive server was
started in 2007 and has far cleaner code. Its random
number generator, for example, uses a smaller, simpler, and more
secure cryptographic algorithm; its configuration file parser uses a
finite state machine interpreter; its handling of multiple simultaneous
pending connections is done using select() and a state machine
instead of with threads.
Deadwood's source code
can be browsed online, and there are a number of documents
describing its internals available.
Other DNS servers
The landscape of open-source DNS servers has changed greatly since
2001 when MaraDNS was started. There are now a number of different
DNS servers still actively developed and maintained: BIND, Power DNS,
NSD/Unbound, as well as MaraDNS. DjbDNS is no longer being
updated and the unofficial forks have limited support;
notably it took nearly five months for someone to come up with a
MaraDNS' strength is that it's a remarkably small, lightweight,
easy to configure, and mostly cross-platform DNS server.
Deadwood is a tiny DNS server with full recursion
support, perfect for embedded systems.
MaraDNS' weakness is that it does not have some features other
DNS servers have. For example, while Deadwood has the strongest
spoof protection available without cryptography,
it does not have support for DNSSEC.
As another example, MaraDNS does not have full zone transfer support;
while MaraDNS can both serve zones and receive external zone files from
other DNS servers, MaraDNS needs to be restarted to update its
database of DNS records.
It would require some large company or government agency paying me
a full-time living wage to add significant new features to MaraDNS.
Since this is unlikely to happen, especially in today's economy, I
am declaring MaraDNS finished: While I will still fix important
security bugs in MaraDNS, and will probably still fix other critical
bugs, I currently have no plans to add new features to MaraDNS.