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Name Synopsis Table of Contents Description Usage Firewall Configuration Frequently Asked Questions Bugs Unimplemented Features Legal Disclaimer Authors
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
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.
Please note that, in order to reload a zone file, it is necessary to restart MaraDNS and reload all zone files. MaraDNS uses a hash data format which loads records very quickly from memory, but requires a restart to update.
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.
When using the Deadwood recursive nameserver:
1. I'm using an older version of MaraDNS3. 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
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?
26. I am having problems setting upstream_servers
27. Why doesn't the MaraDNS.org web page validate?
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.
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.
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?
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?
MaraDNS 1 is no longer supported; support ended on June 21, 2015.
Read the quick start guide, which is the file named 0QuickStart in the MaraDNS distribution.
Copyright (c) 2002-2016 Sam Trenholme and othersTERMS
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.
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.
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 10.2.3.4If 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.
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.timeout_seconds = 5
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.
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.
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
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.
There are no plans to add new features to MaraDNS or Deadwood at this time.
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.
I no longer accept third party patches
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.
Yes.
Please read the DNS slave document, which is part of the MaraDNS tutorial.
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.
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:
MaraDNS is developed in CentOS 6 and Windows 7. MaraDNS may or may not compile and run on other systems.
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.
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.
There is no other integration with Python.
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.
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"
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.
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'
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
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 10.2.3.11Then 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 10.2.3.11This 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.
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.
In more detail, MaraDNS does not use autoconf for the following reasons:
There is, however, a CentOS 5-compatible RPM spec file in the build directory.
Since MaraDNS is finished, updates usually only happen about once a year.
The last security bug which required a MaraDNS update was made before September 28, 2015.
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.
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.
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.
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:
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.
The procedure for subscribing to the mailing list is as follows:
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.
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.
#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.
http://samiam.org/blog/20120326.html
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.
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.
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.
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.
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”
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.
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.
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
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.
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.
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.