Provided by: maradns_2.0.13-1.4+deb11u1build0.22.04.1_amd64 
NAME
maradns - DNS server
SYNOPSIS
maradns [ -v | -f mararc_file_location ]
TABLE OF CONTENTS
This man page has the following sections:
Name
Synopsis
Table of Contents
Description
Usage
Firewall Configuration
Frequently Asked Questions
Bugs
Unimplemented Features
Legal Disclaimer
Authors
DESCRIPTION
maradns is a DNS server written with security, simplicity, and performance in mind.
maradns has two forms of arguments, both of which are optional.
The first is the location of a mararc file which MaraDNS obtains all configuration
information from. The default location of this file is /etc/mararc. This is specified in
the form maradns -f mararc_file_location; mararc_file_location is the location of the
mararc file.
It is also possible to have MaraDNS display the version number and exit. This is specified
by invoking maradns in the form maradns -v or maradns --version
USAGE
MaraDNS consists of two programs: maradns, an authoritative-only nameserver, and Deadwood,
a recursive name server. Deadwood has its own man page.
In order for MaraDNS to function as an authoritative nameserver, two or more files need to
be set up: the mararc file and one or more "csv2" (or "csv1") zone files.
The format of a csv2 zone file can be obtained from the csv2(5) manual page. The
configuration format of the mararc file can be obtained from the mararc(5) manual page.
In order to have MaraDNS run as a daemon, the duende program is used to daemonize MaraDNS.
See the duende(8) manual page for details.
FIREWALL CONFIGURATION
When using the maradns authoritative nameserver, allow UDP connections from all hosts on
the internet to UDP port 53 for the IP that the authoritative nameserver uses.
When using the Deadwood recursive nameserver:
* Allow UDP connections from the Deadwood server to any machine on the internet where the
UDP destination port is 53
* Allow UDP connections from any machine on the internet to the IP of the recursive
server, where the source port from the remote server is 53, and the destination port is
between 15000 and 19095 (inclusive)
* Allow UDP connections from IPs that use Deadwood as a recursive DNS server to port 53
Deadwood uses a strong secure RNG (RadioGatun[32]) for both the query (16 bits of entropy)
and the source port of the query (12 bits of entropy). This makes spoofing replies to a
Deadwood recursive server more difficult, since the attacker has only a one in 250 million
chance that a given spoofed reply will be considered valid.
FREQUENTLY ASKED QUESTIONS
INDEX
1. I'm using an older version of MaraDNS
2. How do I try out MaraDNS?
3. What license is MaraDNS released under?
4. How do I report bugs in MaraDNS?
5. Some of the postings to the mailing list do not talk about MaraDNS!
6. How do I get off the mailing list?
7. How do I set up reverse DNS on MaraDNS?
8. I am on a slow network, and MaraDNS can not process recursive queries
9. When I try to run MaraDNS, I get a cryptic error message.
10. After I start MaraDNS, I can not see the process when I run netstat -na
11. What string library does MaraDNS use?
12. Why does MaraDNS use a multi-threaded model?
13. I feel that XXX feature should be added to MaraDNS
14. I feel that MaraDNS should use another documentation format
15. Is there any process I need to follow to add a patch to MaraDNS?
16. Can MaraDNS act as a primary nameserver?
17. Can MaraDNS act as a secondary nameserver?
18. What is the difference between an authoritative and a recursive DNS server?
19. The getzone client isn't allowing me to add certain hostnames to my zone
20. Is MaraDNS portable?
21. Can I use MaraDNS in Windows?
22. MaraDNS freezes up after being used for a while
23. What kind of Python integration does MaraDNS have
24. Doesn't "kvar" mean "four" in Esperanto?
25. How scalable is MaraDNS?
26. I am having problems setting upstream_servers
27. Why doesn't the MaraDNS.org web page validate?
28. How do MX records work?
29. Does MaraDNS have support for SPF?
30. I'm having problems resolving CNAMES I have set up.
31. I have a NS delegation, and MaraDNS is doing strange things.
32. I am transferring a zone from another server, but the NS records are these strange
"synth-ip" records.
33. Where is the root.hints file?
34. Are there any plans to use autoconf to build MaraDNS?
35. How do I change the compiler or compile-time flags with MaraDNS' build process?
36. Will you make a package for the particular Linux distribution I am using?
37. I am using the native Windows port of MaraDNS, and some features are not working.
38. MaraDNS isn't starting up
39. You make a lot of releases of MaraDNS; at our ISP/IT department, updating software
is non-trivial.
40. I have star records in my zones, and am having problems with NXDOMAINs/IPV6
resolution
41. I have a zone with only SOA/NS records, and the zone is not working.
42. I am having problems registering my domain with AFNIC (the registrar for .fr
domains)
43. I can't see the full answers for subdomains I have delegated
44. MaraDNS 1 has a problem resolving a domain
45. MaraDNS 1.2 has issues with NXDOMAINS and case sensitivity.
46. Can MaraDNS offer protection from phishing and malicious sites?
47. Does maradns support star (wildcard) records?
48. I'm having problems using MaraDNS with some *NIX command line applications like
telnet
49. My virus scanner reports that MaraDNS or Deadwood has a virus
50. I can not subscribe to the MaraDNS mailing list
51. How does MaraDNS respond to EDNS (RFC2671) packets?
52. How to I get MaraDNS to always give the same IP to all DNS queries?
53. Why did you change MaraDNS' tagline?
54. How do you stop MaraDNS from taking part in a distributed denial-of-service
attack?
55. What about DNS-over-TCP?
56. How do I use MaraDNS with systemd?
57. Why doesn't MaraDNS use IP_FREEBIND?
58. Is there a web interface for MaraDNS?
59. What does the message “don’t forget the trailing dot” mean?
60. Does MaraDNS support newer top level domains?
ANSWERS
1. I'm using an older version of MaraDNS
Upgrade to MaraDNS 2.0. Here is an upgrade guide.
MaraDNS 1.4 is only supported for critical security updates; this support is being phased
out and MaraDNS 1 will no longer be supported on June 21, 2015.
2. How do I try out MaraDNS?
Read the quick start guide, which is the file named 0QuickStart in the MaraDNS
distribution.
3. What license is MaraDNS released under?
MaraDNS is released with the following two-clause BSD-type license:
Copyright (c) 2002-2015 Sam Trenholme and others
TERMS
Redistribution and use in source and binary forms, with or without modification, are
permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of
conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list
of conditions and the following disclaimer in the documentation and/or other materials
provided with the distribution.
This software is provided 'as is' with no guarantees of correctness or fitness for
purpose.
4. How do I report bugs in MaraDNS?
Post your bug report as a Github issue.
5. Some of the postings to the mailing list do not talk about MaraDNS!
As of September 2013, the mailing list has become moderated and only postings on the
mailing list are relevant MaraDNS announcements.
6. How do I get off the mailing list?
Send an email to list-unsubscribe@maradns.org, or an email to list-request@maradns.org
with "unsubscribe" as the subject line.
The mailing list will send you an email confirming the unsubscribe request; this email
needs to be replied to in order to get off the list.
7. How do I set up reverse DNS on MaraDNS?
Reverse DNS (sometimes called "reverse mapping") is set up by using PTR (pointer) records.
For example, the PTR record which performs the reverse DNS lookup for the ip 10.2.3.4
looks like this in a CSV2 zone file:
4.3.2.10.in-addr.arpa. PTR www.example.com.
It is also possible to use a special "FQDN4" which automatically sets up the reverse
mapping of a given record:
www.example.com. FQDN4 10.2.3.4
If you wish to have a PTR (reverse DNS lookup; getting a DNS name from a numeric IP)
record work on the internet at large, it is not a simple matter of just adding a record
like this to a MaraDNS zonefile. One also needs control of the appropriate in-addr.arpa.
domain.
While it could make logical sense to contact the IP 10.11.12.13 when trying to get the
reverse DNS lookup (fully qualified domain name) for a given IP, DNS servers don't do
this. DNS server, instead, contact the root DNS servers for a given in-addr.arpa name to
get the reverse DNS lookup, just like they do with any other record type.
When an internet service provider is given a block of IPs, they are also given control of
the DNS zones which allow them to control reverse DNS lookups for those IPs. While it is
possible to obtain a domain and run a DNS server without the knowledge or intervention of
an ISP, being able to control reverse DNS lookups for those IPs requires ISP intervention.
8. I am on a slow network, and Deadwood can not process recursive queries
Deadwood, by default, only waits two seconds for a reply from a remote DNS server. This
default can be increased by adding a line like this in the mararc file:
timeout_seconds = 5
Note that making this too high will slow MaraDNS down when DNS servers are down, which is,
alas, all too common on today's internet.
9. When I try to run MaraDNS, I get a cryptic error message.
There is usually some context of where there is a syntax error in a data file before the
cryptic error message. For example, when there is a syntax error in a csv2 zone file,
MaraDNS will tell you exactly at what point it had to terminate parsing of the zone file.
If MaraDNS does return a cryptic error message without letting you know what is wrong, let
us know in a Github issue so that we can fix the bug. MaraDNS is designed to be easy to
use; cryptic error messages go against this spirit.
10. After I start MaraDNS, I can not see the process when I run netstat -na
Udp services do not have a prominent "LISTEN" when netstat is run.
When MaraDNS is up, the relevant line in the netstat output looks like this: udp 0 0
127.0.0.1:53 0.0.0.0:*
While on the topic of netstat, if you run netstat -nap as root on Linux and some other
*nix operating systems, you can see the names of the processes which are providing
internet services.
11. What string library does MaraDNS use?
MaraDNS uses its own string library, which is called the "js_string" library. Man pages
for most of the functions in the js_string library are in the folder doc/man of the
MaraDNS distribution
12. Why does MaraDNS use a multi-threaded model?
MaraDNS 2.0 no longer uses threads.
It took me three years to rewrite MaraDNS' recursive resolver as a separate non-threaded
daemon. This has been done, and now all recursion is done with Deadwood which does not
need threads.
13. I feel that XXX feature should be added to MaraDNS
There are no plans to add new features to MaraDNS or Deadwood at this time.
14. I feel that MaraDNS should use another documentation format
The reason that MaraDNS uses its own documentation format is to satisfy both the needs of
translators to have a unified document format and my own need to use a documentation
format that is simple enough to be readily understood and which I can add features on an
as needed basis.
The documentation format is essentially simplified HTML with some special tags added to
meet MaraDNS' special needs.
This gives me more flexibility to adapt the documentation format to changing needs. For
example, when someone pointed out that it's not a good idea to have man pages with hi-bit
characters, it was a simple matter to add a new HIBIT tag which allows man pages to be
without hi-bit characters, and other document formats to retain hi-bit characters.
Having a given program have its own documentation format is not without precedent; Perl
uses its own "pod" documentation format.
15. Is there any process I need to follow to add a patch to MaraDNS?
I no longer accept third party patches
16. Can MaraDNS act as a primary nameserver?
Yes.
The zoneserver program serves zones so that other DNS servers can be secondaries for zones
which MaraDNS serves. This is a separate program from the maradns server, which processes
authoritative UDP DNS queries, and Deadwood which processes recursive DNS queries.
See the DNS master document in the MaraDNS tutorial for details.
17. Can MaraDNS act as a secondary nameserver?
Yes.
Please read the DNS slave document, which is part of the MaraDNS tutorial.
18. What is the difference between an authoritative and a recursive DNS server?
A recursive DNS server is a DNS server that is able to contact other DNS servers in order
to resolve a given domain name label. This is the kind of DNS server one points to in
/etc/resolv.conf. MaraDNS uses the Deadwood daemon to process recursive DNS queries.
An authoritative DNS server is a DNS server that a recursive server contacts in order to
find out the answer to a given DNS query. The maradns daemon processes authoritative DNS
queries.
19. The fetchzone client isn't allowing me to add certain hostnames to my zone
For security reasons, MaraDNS' fetchzone client does not add records which are not part of
the zone in question. For example, if someone has a zone for example.com, and this record
in the zone:
1.1.1.10.in-addr.arpa. PTR dns.example.com.
MaraDNS will not add the record, since the record is out-of-bailiwick. In other words, it
is a host name that does not end in .example.com.
There are two workarounds for this issue:
* Create a zone file for 1.1.10.in-addr.arpa., and put the PTR records there.
* Use rcp, rsync, or another method to copy over the zone files in question.
20. Is MaraDNS portable?
MaraDNS is developed in CentOS 6 and Windows 7. MaraDNS may or may not compile and run on
other systems.
21. Can I use MaraDNS in Windows?
Yes. There is both a partial mingw32 (native win32 binary) port and a full Cygwin port of
MaraDNS; both of these ports are part of the native build of MaraDNS. Deadwood has full
Windows support, including the ability to run as a service.
22. MaraDNS freezes up after being used for a while
If using your ISP's name servers or some other name servers which are not, in fact, root
name servers, please make sure that you are using the upstream_servers dictionary variable
instead of the root_servers dictionary variable.
If you still see MaraDNS freeze up after making this correction, please send a bug report
as a Github issue.
23. What kind of Python integration does MaraDNS have
The mararc file uses the same syntax that Python uses; in fact, Python can parse a
properly formatted mararc file.
There is no other integration with Python.
24. Doesn't "kvar" mean "four" in Esperanto?
Indeed, it does. However the use of "kvar" in the MaraDNS source code only coincidentally
is an Esperanto word. "kvar" is short for "Kiwi variable"; a lot of the parsing code comes
from the code used in the Kiwi spam filter project.
25. How scalable is MaraDNS?
MaraDNS is optimized for serving a small number of domains as quickly as possible. That
said, MaraDNS is remarkably efficnent for serving a large number of domains, as long as
the server MaraDNS is on has the memory to fit all of the domains, and as long as the
startup time for loading a large number of domains can be worked around.
The "big-O" or "theta" growth rates for various MaraDNS functions are as follows, where N
is the number of authoritative host names being served:
Startup time N
Memory usage N
Processing incoming DNS requests 1
As can be seen, MaraDNS will process 1 or 100000 domains in the same amount of time, once
the domain names are loaded in to memory.
26. I am having problems setting upstream_servers
upstream_servers is only supported by Deadwood, and is no longer supported in MaraDNS 2.0.
The upstream_servers dwood3rc variable is set thusly:
upstream_servers["."] = "10.3.28.79, 10.2.19.83"
Note the ["."].
Note that the upstream_servers variable needs to be initialized before being used via
upstream_servers = {} (the reason for this is so that a dwood3rc file has 100% Python-
compatible syntax). A complete dwood3rc file that uses upstream_servers may look like
this:
ipv4_bind_addresses = "127.0.0.1"
chroot_dir = "/etc/maradns"
recursive_acl = "127.0.0.1/8"
upstream_servers = {}
upstream_servers["."] = "10.1.2.3, 10.2.4.6"
27. Why doesn't the MaraDNS.org web page validate?
HTML pages on the MaraDNS.org web site should validate as HTML 4.0 Transitional. However,
the CSS will not validate.
I have designed MaraDNS' web page to be usable and as attractive as possible in any major
browser released in the last ten years. Cross-browser support is more important than
strict W3 validation. The reason why the CSS does not validate is because I need a way to
make sure there is always a scrollbar on the web page, even if the content is not big
enough to merit one; this is to avoid the content jumping from page to page. There is no
standard CSS tag that lets me do this. I'm using a non-standard tag to enable this in
Gecko (Firefox's rendering engine); this is enabled by default in Trident (Internet
Explorer's rendering engine). The standards are deficient and blind adherence to them
would result in an inferior web site.
There are also two validation warnings generated by redefinitions which are needed as part
of the CSS filters used to make the site attractive on older browsers with limited CSS
support.
On a related note, the reason why I use tables instead of CSS for some of the layout is
because Microsoft Internet Explorer 6 and other browsers do not have support for the max-
width CSS property. Without this property, the web page will not scale down correctly
without using tables. Additionally, tables allow a reasonably attractive header in
browsers without CSS support.
28. How do MX records work?
How MX records work:
* The mail transport agent (Sendmail, Postfix, Qmail, MS Exchange, etc.) looks up the MX
record for the domain
* For each of the records returned, the MTA (mail transport agent) looks up the IP for the
names.
* It will choose, at random, any of the MXes with the lowest priority number.
* Should that server fail, it will try another server with the same priority number.
* Should all MX records with a given priority number fail, the MTA will try sending email
to any of the MX records with the second-lowest priority value.
As an aside, do not have MX records point to CNAMEs.
29. Does MaraDNS have support for SPF?
SPF, or sender policy framework, is method of using DNS that makes it more difficult to
forge email. MaraDNS has full support for SPF, both via TXT records and RFC4408 SPF
records.
SPF configuration is beyond the scope of MaraDNS' documentation. However, at the time
this FAQ entry was last updated (July, 2013), information and documentation concerning SPF
is available at http://openspf.org. The BIND examples will work in MaraDNS csv2 zone files
as long as the double quotes (") are replaced by single quotes ('). For example, a SPF TXT
record that looks like example.net. IN TXT "v=spf1 +mx a:colo.example.com/28 -all" in a
BIND zone file will look like example.net. TXT 'v=spf1 +mx a:colo.example.com/28 -all' in
a MaraDNS zone file. MaraDNS can also make the corresponding SPF record, which will have
the syntax example.net. SPF 'v=spf1 +mx a:colo.example.com/28 -all'.
Use '\x7e' to put a tilde ("~" character) in a SPF record:
example.com. SPF 'v=spf1 +mx a:colo.example.com/28 '\x7e'all'
30. I'm having problems resolving CNAMES I have set up.
This is probably because you have set up what MaraDNS calls a dangling CNAME record.
Let us suppose we have a CNAME record without an A record in the local DNS server's
database, such as:
google.example.com. CNAME www.google.com.
This record, which is a CNAME record for "google.example.com", points to "www.google.com".
Some DNS servers will recursively look up www.google.com, and render the above record like
this:
google.example.com. CNAME www.google.com.
www.google.com. A 66.102.7.104
For security reasons, MaraDNS doesn't do this. Instead, MaraDNS will simply output:
google.example.com. CNAME www.google.com.
Some stub resolvers will be unable to resolve google.example.com as a consequence.
If you set up MaraDNS to resolve CNAMEs thusly, you will get a warning in your logs about
having a dangling CNAME record.
If you want to remove these warnings, add the following to your mararc file:
no_cname_warnings = 1
Information about how to get MaraDNS to resolve dangling CNAME records is in the tutorial
file dangling.html
31. I have a NS delegation, and MaraDNS is doing strange things.
This is only an issue in MaraDNS 1.4. MaraDNS 2.0 does not allow the same IP to both
authoritatively and recursively resolve records.
32. I am transferring a zone from another server, but the NS records are these strange
"synth-ip" records.
MaraDNS expects, in csv2 zone files, for all delegation NS records to be between the SOA
record and the first non-NS record.
If a zone looks like this:
example.net. +600 soa ns1.example.net.
hostmaster@example.net 10 10800 3600 604800 1080
example.net. +600 mx 10 mail.example.net.
example.net. +600 a 10.2.3.5
example.net. +600 ns ns1.example.net.
example.net. +600 ns ns3.example.net.
mail.example.net. +600 a 10.2.3.7
www.example.net. +600 a 10.2.3.11
Then the NS records will be "synth-ip" records.
The zone should look like this:
example.net. +600 soa ns1.example.net.
hostmaster@example.net 10 10800 3600 604800 1080
example.net. +600 ns ns1.example.net.
example.net. +600 ns ns3.example.net.
example.net. +600 mx 10 mail.example.net.
example.net. +600 a 10.2.3.5
mail.example.net. +600 a 10.2.3.7
www.example.net. +600 a 10.2.3.11
This will remove the "synth-ip" records.
To automate this process, this awk script is useful:
fetchzone whatever.zone.foo 10.1.2.3 | awk '
{if($3 ~ /ns/ || $3 ~ /soa/){print}
else{a = a "\n" $0}}
END{print a}' > zonefile.csv2
Replace "whatever.zone.foo" with the name of the zone you are fetchin 10.1.2.3 with the IP
address of the DNS master, and zonefile.csv2 with the name of the zone file MaraDNS loads.
33. Where is the root.hints file?
MaraDNS (actually, Deadwood), unlike BIND, does not need a complicated root.hints file in
order to have custom root servers. In order to change the root.hints file, add something
like this to your dwood3rc file:
root_servers["."] = "131.161.247.232,"
root_servers["."] += "208.185.249.250,"
root_servers["."] += "66.227.42.140,"
root_servers["."] += "66.227.42.149,"
root_servers["."] += "65.243.92.254"
Note that there is no "+=" in the first line, and the last line does not have a comma at
the end. Read the recursive tutorial document for more information.
34. Are there any plans to use autoconf to build MaraDNS?
No.
In more detail, MaraDNS does not use autoconf for the following reasons:
* Autoconf is designed to solve a problem that existed in the mid 1990s but does not exist
today: A large number of different incompatible C compilers and libc implementations.
These days, most systems are using gcc as the compiler and some version of glibc as the
libc. There is no longer a need, for example, to figure out whether a given
implementation of getopt() allows '--' options. MaraDNS's ./configure script can be run
in only a second or two; compare this to the 3-5 minute process autoconf's ./configure
needs.
* Autoconf leaves GPL-tained files in a program's build tree. MaraDNS is licensed under a
BSD license that is not GPL-compatible, so MaraDNS can not be distributed with these
GPL-licensed files.
This leads us to the next question:
35. How do I change the compiler or compile-time flags with MaraDNS' build process?
To change the compiler used by MaraDNS:
* Run the ./configure script
* Open up the file Makefile with an editor
* Look for a line that starts with CC
* If there is no line that starts with CC, create one just before the line that starts
with FLAGS
* Change (or create) that line to look something like CC=gcc296 In this example, the 2.96
version of gcc is used to compile MaraDNS.
* Note that it is important to not remove anything from this line you do not understand;
doing so will make MaraDNS unable to compile or run. So, if the CC line looks like
CC=gcc $(LDFLAGS) -DNO_FLOCK and you want to compile with gcc 2.96, change the
line to look like CC=gcc296 $(LDFLAGS) -DNO_FLOCK retaining the flags added by
the configuration script.
Changing compile-time flags is a similar process:
* Run the ./configure script
* Open up the file Makefile with an editor
* Look for a line that starts with FLAGS
* Change (or create) that line to look something like FLAGS=-O3 In this example, MaraDNS
is compiled with the -O3 option.
* Note that it is important to not remove anything from this line you do not understand;
doing so will make MaraDNS unable to compile or run. So, if the FLAGS line looks like
FLAGS=-O2 -Wall -DSELECT_PROBLEM and you want to compile at optimization level
three, change this line to look like FLAGS=-O2 -Wall -DSELECT_PROBLEM
retaining the flags added by the configuration script. -DSELECT_PROBLEM for example, is
needed in the Linux compile or MaraDNS will have problems with freezing up.
36. Will you make a package for the particular Linux distribution I am using?
No.
There is, however, a CentOS 5-compatible RPM spec file in the build directory.
37. I am using the native Windows port of MaraDNS, and some features are not working.
Since Windows 32 does not have some features that *NIX OSes have, the native Windows port
does not have all of the features of the *NIX version of MaraDNS. In particular, the
following features are disabled:
* ipv6 (this is actually a mingw32, not a Windows deficiency)
* The chroot_dir mararc variable
* The maradns_gid and maradns_uid mararc variables
* The maxprocs mararc variable
* The synth_soa_serial variable can not have a value of 2
* There is no DNS-over-TCP support
If any of the above features are desired, try compiling MaraDNS using Cygwin. Note that
the Cygwin port of MaraDNS does not have ipv6 support, and that while chroot_dir works in
Cygwin, it does not have the security that the *NIX chroot() call has.
38. MaraDNS isn't starting up
This is usually caused by a syntax error in one's mararc file, or by another MaraDNS
process already running. To see what is happening, look at your system log
(/var/log/messages in Centos 3) to see what errors MaraDNS reports. If you do not know how
to look at a system log, you can also invoke MaraDNS from the command line as root; any
errors will be visible when starting MaraDNS.
39. You make a lot of releases of MaraDNS; at our ISP/IT department, updating software is
non-trivial.
Regularly updating software is required to keep something as complicated as a DNS server
secure; there is not a DNS server out there so secure that it never needs to be updated.
Since MaraDNS is finished, updates usually only happen about once a year.
The last security bug which required a MaraDNS update was made before January 30, 2015.
40. I have star records in my zones, and am having problems with NXDOMAINs/IPV6 resolution
This was a bug in MaraDNS 1.2 which has long since been fixed.
41. I have a zone with only SOA/NS records, and the zone is not working.
MaraDNS 1.2 had a bug where it did not correctly process zones without any "normal"
records. Upgrade to MaraDNS 2.0.
42. I am having problems registering my domain with AFNIC (the registrar for .fr domains)
Because of an issue with AFNIC (who, annoyingly enough, check the RA bit when registering
a domain), in order to register a domain with AFNIC using MaraDNS as your DNS server, the
following steps need to be followed:
* MaraDNS version 1.4 or 2.0 needs to be used; if you're using an older version of
MaraDNS, upgrade.
* It is necessary to have recursion disabled, if using MaraDNS 1.4, either by compiling
MaraDNS without recursive support (./configure --authonly ; make), or by making sure
MaraDNS does not have recursion enabled (by not having recursive_acl set in one's
MaraDNS 1.4 mararc file)
If one wishes to both register domains with AFNIC and use MaraDNS 1.4 as a recursive DNS
server, it is required to have the recursive server be a separate instance of MaraDNS on a
separate IP. It is not possible to have the same DNS server both send DNS packets in a way
that both makes AFNIC happy and allows recursive queries.
Note also: AFNIC gives warnings about reverse DNS lookups; more information about this
issue can be found in the FAQ entry about reverse DNS mappings (question 7). In addition,
AFNIC requires DNS-over-TCP to work; information on configuring MaraDNS to have this can
be found in the DNS-over-TCP tutorial.
43. I can't see the full answers for subdomains I have delegated
To have the subdomains be visible to MaraDNS 1.4 recursive nameservers, add the following
to your mararc file:
recurse_delegation = 1
44. MaraDNS 1 has a problem resolving a domain
This issue should be fixed in MaraDNS 2.0.
Here's what happening: I have rewritten the recursive resolver for MaraDNS. The old code
was always designed to be a placeholder until I wrote a new recursive resolver.
The new recursive resolver is called "Deadwood"; right now it's fully functional and part
of MaraDNS 2.0. More information is here:
http://maradns.blogspot.com/search/label/Deadwood
http://maradns.samiam.org/deadwood/
Since the old recursive code is a bit difficult to maintain, and since I in the process of
rewriting the recursive code, my rule is that I will only resolve security issues with
MaraDNS 1.0's recursive resolver.
45. MaraDNS 1.2 had issues with NXDOMAINS and case sensitivity.
There was a known bug in MaraDNS 1.2.12 where, should a client ask for a non-existent
record in all caps, MaraDNS 1.2.12 will return a NXDOMAIN instead of a "not there" reply.
Upgrade to 2.0.
46. Can MaraDNS offer protection from phishing and malicious sites?
Deadwood can block up to about 20,000 domains. More details are in the Deadwood FAQ.
47. Does maradns support star (wildcard) records?
Yes.
MaraDNS supports both having stars at the beginning of records and the end of records. For
example, to have anything.example.com. have the IP 10.1.2.3, add this line to the zone
file for example.com:
*.example.com. A 10.1.2.3
To have stars at the end of records, csv2_default_zonefile has to be set. The mararc
parameter bind_star_handling affects how star records are handled. More information is in
the mararc man page.
48. I'm having problems using MaraDNS with some *NIX command line applications like telnet.
Some *NIX command line networking applications, such as telnet and ssh, try to do either a
reverse DNS lookup (IP-to-host name conversion) or an IPv6 lookup. This slows things down
and sometimes causes the applications to not work at all.
For people who do not need IPv6 lookups, add the following line to one's mararc file to
have MaraDNS respond to all IPv6 lookups with a bogus "not found" reply:
reject_aaaa = 1
If knowing the hostname a given IP has isn't important, these kinds of lookups can also be
disabled:
reject_ptr = 1
49. My virus scanner reports that MaraDNS or Deadwood has a virus
This can be caused either by a poorly written anti-virus program reporting a false
positive, or because a virus on your system has infected your copy of MaraDNS/Deadwood.
Please use GPG to verify that the file which your scanner reports having a virus in has
not been altered. In addition, please scan the file with AVG (free for non-commercial
use) to verify your virus scanner has not reported a false positive.
If you have verified the GPG signature of the program and AVG reports a virus, please let
us know with a Github issue. Otherwise, please use a better virus scanner and make sure
there are no viruses on your computer.
50. I can not subscribe to the MaraDNS mailing list
Please note that the mailing list is no longer used to handle MaraDNS support requests.
Please file a Github issue at https://github.com/samboy/MaraDNS/issues to file a MaraDNS
bug report.
The procedure for subscribing to the mailing list is as follows:
* Send an email to list-request@maradns.org with "Subscribe" as the subject, or an email
to list-subscribe@maradns.org
* You will get an email from list-request@maradns.org asking you to confirm your
subscription. This can be done by replying to the message, or, more simply, by clicking
on the link in the message.
* Once you click on that link, click on the button marked "subscribe to list list"
* You will now get a message stating 'Welcome to the "list" mailing list'.
* Note that the mailing list is moderated and only relevant MaraDNS announcements are
approved. People who need help should read the manuals or search the MaraDNS webpage for
support.
If you get an email from list-request@maradns.org with the subject "The results of your
email commands", you did not correctly send an email to list-request@maradns.org with the
subject "Subscribe".
If you do not get the email from list-request@maradns.org asking you for a confirmation,
ensure that this email is not in your "spam" or "junk mail" folder. If you are unable to
get these emails at your email address, please get a gmail email account, which can
successfully subscribe to the MaraDNS mailing list. Note that subscription confirmation
emails may be in Gmail's "promotions" tab.
51. How does MaraDNS respond to EDNS (RFC2671) packets?
MaraDNS 2 (both the authoritative maradns server and the recursive Deadwood server)
responds to EDNS packets by ignoring the OPT record and acting as if it the packet did not
have an OPT record.
MicroDNS (available in the tools/misc directory of any MaraDNS 2 release) responds to EDNS
queries the same way Deadwood 2.9.03 did: By giving back "NOTIMPL" instead of answering
the query with the default IP. NanoDNS, in the interest of minimizing code side, responds
to EDNS requests by returning NOTIMPL in the header, giving the OPT query in the AN
section of the response, and giving the default IP in the AR section of the DNS reply
packet.
52. How to I get MaraDNS to always give the same IP to all DNS queries?
There are three ways to have MaraDNS always give the same IP in reply to any DNS query
given to it:
* The best way to do this is to set up a default zonefile that causes any and all A
queries to always give the IP (and also allows all AAAA queries to always give out the
same IP6, all SPF or TXT queries to give out the same SPF record, etc.).
* Another possibility, if someone just wants a simple DNS server that always gives out the
same IP address to any and all DNS queries, is to use the MicroDNS program, available in
tools/misc, as well as having its own web page.
* If MicroDNS is too bloated, there is also NanoDNS, which I will include the source code
of below:
/*Placed in the public domain by Sam Trenholme*/
#include <arpa/inet.h>
#include <string.h>
#include <stdint.h>
#define Z struct sockaddr
#define Y sizeof(d)
int main(int a,char **b){uint32_t i;char q[512]
,p[17]="\xc0\f\0\x01\0\x01\0\0\0\0\0\x04";if(a>
1){struct sockaddr_in d;socklen_t f=511;bzero(&
d,Y);a=socket(AF_INET,SOCK_DGRAM,0);*((uint32_t
*)(p+12))=inet_addr(b[1]);d.sin_family=AF_INET;
d.sin_port=htons(53);bind(a,(Z*)&d,Y);for(;;){i
=recvfrom(a,q,255,0,(Z*)&d,&f);if(i>9&&q[2]>=0)
{q[2]|=128;q[11]?q[3]|=4:1;q[7]++;memcpy(q+i,p,
16);sendto(a,q,i+16,0,(Z*)&d,Y);}}}return 0;}
NanoDNS takes one argument: The IP we return. This program binds to all IP addresses a
given machine has on the UDP DNS port (port 53). For example, to make a DNS server that
binds to all IPs your system has and return the IP 10.11.12.13 to any UDP DNS queries sent
to it, compile the above C program, call it NanoDNS, and invoke it with NanoDNS
10.11.12.13 Note that NanoDNS does not daemonize, nor log anything, nor have any other
space-wasting features.
Why did you change MaraDNS' tagline?
I have changed MaraDNS' tagline from "MaraDNS: A security-aware DNS server" to "MaraDNS: A
small open-source DNS server" because MaraDNS does not support DNSSEC. I have blogged
about this:
http://samiam.org/blog/20120326.html
How do you stop MaraDNS from taking part in a distributed denial-of-service attack?
While I do not have time to implement rate limiting, CentOS 6 does support response rate
limiting at the firewall level. The following iptables commands allow a given IP to only
send MaraDNS/Deadwood 20 DNS queries every four seconds:
iptables -A INPUT -p udp --dport 53 -m state --state NEW -m recent --set --name DDOS
--rsource
iptables -A INPUT -p udp --dport 53 -m state --state NEW -m recent --update --seconds 4
--hitcount 20 --name DDOS --rsource -j DROP
To verify they are applied:
iptables --list
To save these commands in CentOS so they are applied at system boot time:
iptables-save > /etc/sysconfig/iptables
Disclaimer
These incantations work in CentOS 6 but may or may not work in other versions of Linux. I
do not support non-CentOS6 Linux installs of MaraDNS.
What about DNS-over-TCP?
For people who want DNS-over-TCP, instructions are in the DNS-over-TCP tutorial. Note that
Windows users will have to use Cygwin to have DNS-over-TCP.
However, DNS-over-TCP is not necessary. DNS-over-TCP is optional as per section 6.1.3.2 of
RFC1123; any program or web service that considers no DNS-over-TCP an error is not RFC-
compliant.
Not having DNS-over-TCP is more secure, because it gives attackers a smaller surface to
attack.
How do I use MaraDNS with systemd?
While I like systemd, it is not part of CentOS 6 nor, obviously, Windows 7. That in mind,
I have no plans to support systemd until 2017, when I plan to update MaraDNS' supported
operating systems.
However, Tomasz Torcz has kindly made some systemd files for MaraDNS, which people are
free to use.
As an aside, I do not like the fact that Debian will probably not make systemd the default
init; I do not think this kind of fragmentation is good for Linux.
Why doesn't MaraDNS use IP_FREEBIND?
IP_FREEBIND is a non-POSIX Linux-specific extension to POSIX's netinet/in.h, and, as such,
has no place in MaraDNS' code. MaraDNS strives to use POSIX-compliant calls so that it can
compile on as many systems as possible.
When I say that Windows 7 and CentOS 6 are the only supported operating systems for
MaraDNS, this does not mean that MaraDNS will not compile and run on other systems; it
merely means that I can not provide support for Github bug reports for people who want to
run MaraDNS in Minix, one of the open-source BSD variants, or what not.
Is there a web interface for MaraDNS?
The Kloxo-MR control panel has MaraDNS support.
What does the message “don’t forget the trailing dot” mean?
It means to not forget the tailing dot.
Hostnames in zone files need to be properly terminated; if a hostname is in the form
“foo.example.com”, this name will not parse and return an error with a note to not forget
the trailing dot.
To fix this, put a trailing dot at the end of the hostname, so it looks like
“foo.example.com.” (observe that dot at the end) instead of “foo.example.com”
Does MaraDNS support newer top level domains?
MaraDNS does not impose any limitations on the top level domain used in zone files and
other places, as is fully compatible with newer top level domains like “today.”
Note that, if using an internationalized domain name, it needs to be translated in to
Punycode first. For example, if using the domain name “ñ.com.”, it needs to be in the form
“xn--ida.com.” in MaraDNS’ mararc and zone files.
BUGS
In the unusual case of having a csv2 zone file with Macintosh-style newlines (as opposed
to DOS or UNIX newlines), while the file will parse, any errors in the file will be
reported as being on line 1.
The system startup script included with MaraDNS assumes that the only MaraDNS processes
running are started by the script; it stops all MaraDNS processes running on the server
when asked to stop MaraDNS.
MaraDNS needs to use the zoneserver program to serve DNS records over TCP. See
zoneserver(8) for usage information.
MaraDNS does not use the zone file ("master file") format specified in chapter 5 of
RFC1035; however bind2csv2.py can convert the majority of such zone files.
MaraDNS default behavior with star records is not RFC-compliant. In more detail, if a
wildcard MX record exists in the form "*.example.com", and there is an A record for
"www.example.com", but no MX record for "www.example.com", the correct behavior (based on
RFC1034 section 4.3.3) is to return "no host" (nothing in the answer section, SOA in the
authority section, 0 result code) for a MX request to "www.example.com". Instead, MaraDNS
returns the MX record attached to "*.example.com". This can be changed by setting
bind_star_handling to 1.
Star records (what RFC1034 calls "wildcards") can not be attached to NS records.
MaraDNS, like every other known DNS implementation, only supports a QDCOUNT of 0 or 1.
UNIMPLEMENTED FEATURES
These are features which I do not plan to implement in MaraDNS.
MaraDNS does not have a disk-based caching scheme for authoritative zones.
MaraDNS' UDP server only loads zone files while MaraDNS is first started. UDP Zone
information can only be updated by stopping MaraDNS, and restarting MaraDNS again. Note
that TCP zone files are loaded from the filesystem at the time the client requests a zone.
MaraDNS does not have support for allowing given host names to only resolve for a limited
range of IPs querying the DNS server, or for host names to resolve differently, depending
on the IP querying the host name.
MaraDNS only allows wildcards at the beginning or end of a host name. E.g. names with
wildcards like "foo.*.example.com". "www.*" will work, however, if a default zonefile is
set up. Likewise, MaraDNS does not have regular expression hostname substitution.
MaraDNS does not have support for MRTG or any other SNMP-based logging mechanism.
LEGAL DISCLAIMER
THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
DAMAGE.
AUTHORS
Sam Trenholme (http://www.samiam.org) is responsible for this man page.
MaraDNS is written by me, Sam Trenholme, with a little help from my friends. Naturally,
all errors in MaraDNS are my own (but read the disclaimer above).
Here is a partial list of people who have provided assistance:
Floh has generously set up a FreeBSD 4, FreeBSD 6, and Mac OS X system so that I can port
MaraDNS to more platforms.
Albert Lee has provided countless bug reports, and, nicely enough, patches to fix said
bugs. He has also made improvements to the code in the tcp "zoneserver".
Franky Van Liedekerke has provided much invaluable assistance. As just one example, he
provided invaluable assistance in getting MaraDNS to compile on Solaris. In addition, he
has provided much valuable SQA help.
Christian Kurz, who has provided invaluable bug reports, especially when I had to re-
implement the core hashing algorithm.
Remmy, who is providing both the web space and a mailing list for maradns.org.
Phil Homewood, who provided invaluable assistance with finding and fixing bugs in the
authoritative portion of the MaraDNS server. He helped me plug memory leaks, find
uninitialized variables being used, and found a number of bugs I was unable to find.
Albert Prats kindly provided Spanish translations for various text files.
Shin Zukeran provided a patch to recursive.c which properly makes a normal null-terminated
string from a js_string object, to send as an argument to open() so we can get the
rijndael key for the PRNG.
D Richard Felker III has provided invaluable bug reports. By looking at his bug reports, I
have been able to hunt down and fix many problems that the recursive nameserver had, in
addition to at least one problem with the authoritative nameserver.
Ole Tange has also given me many valuable MaraDNS bug reports.
Florin Iucha provided a tip in the FAQ for how to compile MaraDNS on OpenBSD.
Roy Arends (one of the BIND developers, as it turns out) found a serious security problem
with MaraDNS, where MaraDNS would answer answers, and pointed it out to me.
Code used as the basis for the psudo-random-number generator was written by Vincent
Rijmen, Antoon Bosselaers, and Paulo Barreto. I appreciate these programmers making the
code public domain, which is the only license under which I can add code to MaraDNS under.
Ross Johnson and others have made a Win32 port of the Pthreads library; this has made a
native win32 port of MaraDNS possible.
I also appreciate the work of Dr. Brian Gladman and Fritz Schneider, who have both written
independent implementations of AES from which I obtained test vectors. With the help of
their hard work, I was able to discover a subtle security problem that previous releases
of MaraDNS had.