1MARADNS(8) MaraDNS reference MARADNS(8)
2Erre con erre cigarro
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9
12 maradns - DNS server
13
15 maradns [ -v | -f mararc_file_location ]
16
18 This man page has the following sections:
19 Name
21 Synopsis
22 Table of Contents
23 Description
24 Usage
25 Firewall Configuration
26 Frequently Asked Questions
27 Bugs
28 Unimplemented Features
29 Legal Disclaimer
30 Authors
31
34 maradns is a DNS server written with security, simplicity, and
35 performance in mind.
36 maradns has two forms of arguments, both of which are optional.
38 The first is the location of a mararc file which MaraDNS obtains all
40 configuration information from. The default location of this file is
41 /etc/mararc. This is specified in the form maradns -f
42 mararc_file_location; mararc_file_location is the location of the
43 mararc file.
44 It is also possible to have MaraDNS display the version number and
46 exit. This is specified by invoking maradns in the form maradns -v or
47 maradns --version
48
50 MaraDNS consists of two programs: maradns, an authoritative-only
51 nameserver, and Deadwood, a recursive name server. Deadwood has its own
52 man page.
53 In order for MaraDNS to function as an authoritative nameserver, two or
55 more files need to be set up: the mararc file and one or more "csv2"
56 (or "csv1") zone files.
57 The format of a csv2 zone file can be obtained from the csv2(5) manual
59 page. The configuration format of the mararc file can be obtained from
60 the mararc(5) manual page.
61 In order to have MaraDNS run as a daemon, the duende program is used to
63 daemonize MaraDNS. See the duende(8) manual page for details.
64
66 When using the maradns authoritative nameserver, allow UDP connections
67 from all hosts on the internet to UDP port 53 for the IP that the
68 authoritative nameserver uses.
69 When using the Deadwood recursive nameserver:
71 * Allow UDP connections from the Deadwood server to any machine on the
73 internet where the UDP destination port is 53
74 * Allow UDP connections from any machine on the internet to the IP of
76 the recursive server, where the source port from the remote server is
77 53, and the destination port is between 15000 and 19095 (inclusive)
78 * Allow UDP connections from IPs that use Deadwood as a recursive DNS
80 server to port 53
81 Deadwood uses a strong secure RNG (RadioGatun[32]) for both the query
83 (16 bits of entropy) and the source port of the query (12 bits of
84 entropy). This makes spoofing replies to a Deadwood recursive server
85 more difficult, since the attacker has only a one in 250 million chance
86 that a given spoofed reply will be considered valid.
87
89 INDEX
90 1. I'm using an older version of MaraDNS
92 2. How do I try out MaraDNS?
94 3. What license is MaraDNS released under?
96 4. How do I report bugs in MaraDNS?
98 5. Some of the postings to the mailing list do not talk about
100 MaraDNS!
101 6. How do I get off the mailing list?
103 7. How do I set up reverse DNS on MaraDNS?
105 8. I am on a slow network, and MaraDNS can not process recursive
107 queries
108 9. When I try to run MaraDNS, I get a cryptic error message.
110 10. After I start MaraDNS, I can not see the process when I run
112 netstat -na
113 11. What string library does MaraDNS use?
115 12. Why does MaraDNS use a multi-threaded model?
117 13. I feel that XXX feature should be added to MaraDNS
119 14. I feel that MaraDNS should use another documentation format
121 15. Is there any process I need to follow to add a patch to
123 MaraDNS?
124 16. Can MaraDNS act as a primary nameserver?
126 17. Can MaraDNS act as a secondary nameserver?
128 18. What is the difference between an authoritative and a recursive
130 DNS server?
131 19. The getzone client isn't allowing me to add certain hostnames
133 to my zone
134 20. Is MaraDNS portable?
136 21. Can I use MaraDNS in Windows?
138 22. MaraDNS freezes up after being used for a while
140 23. What kind of Python integration does MaraDNS have
142 24. Doesn't "kvar" mean "four" in Esperanto?
144 25. How scalable is MaraDNS?
146 26. I am having problems setting upstream_servers
148 27. Why doesn't the MaraDNS.org web page validate?
150 28. How do MX records work?
152 29. Does MaraDNS have support for SPF?
154 30. I'm having problems resolving CNAMES I have set up.
156 31. I have a NS delegation, and MaraDNS is doing strange things.
158 32. I am transferring a zone from another server, but the NS
160 records are these strange "synth-ip" records.
161 33. Where is the root.hints file?
163 34. Are there any plans to use autoconf to build MaraDNS?
165 35. How do I change the compiler or compile-time flags with
167 MaraDNS' build process?
168 36. Will you make a package for the particular Linux distribution I
170 am using?
171 37. I am using the native Windows port of MaraDNS, and some
173 features are not working.
174 38. MaraDNS isn't starting up
176 39. You make a lot of releases of MaraDNS; at our ISP/IT
178 department, updating software is non-trivial.
179 40. I have star records in my zones, and am having problems with
181 NXDOMAINs/IPV6 resolution
182 41. I have a zone with only SOA/NS records, and the zone is not
184 working.
185 42. I am having problems registering my domain with AFNIC (the
187 registrar for .fr domains)
188 43. I can't see the full answers for subdomains I have delegated
190 44. MaraDNS 1 has a problem resolving a domain
192 45. MaraDNS 1.2 has issues with NXDOMAINS and case sensitivity.
194 46. Can MaraDNS offer protection from phishing and malicious sites?
196 47. Does maradns support star (wildcard) records?
198 48. I'm having problems using MaraDNS with some *NIX command line
200 applications like telnet
201 49. My virus scanner reports that MaraDNS or Deadwood has a virus
203 50. I can not subscribe to the MaraDNS mailing list
205 51. How does MaraDNS respond to EDNS (RFC2671) packets?
207 52. How to I get MaraDNS to always give the same IP to all DNS
209 queries?
210 53. Why did you change MaraDNS' tagline?
212 54. How do you stop MaraDNS from taking part in a distributed
214 denial-of-service attack?
215 55. What about DNS-over-TCP?
217 56. How do I use MaraDNS with systemd?
219 57. Why doesn't MaraDNS use IP_FREEBIND?
221 58. Is there a web interface for MaraDNS?
223 59. What does the message “don’t forget the trailing dot” mean?
225 60. Does MaraDNS support newer top level domains?
227 ANSWERS
229 1. I'm using an older version of MaraDNS
231 Upgrade to MaraDNS 2.0. Here is an upgrade guide.
233 MaraDNS 1.4 is only supported for critical security updates; this
235 support is being phased out and MaraDNS 1 will no longer be supported
236 on June 21, 2015.
237 2. How do I try out MaraDNS?
239 Read the quick start guide, which is the file named 0QuickStart in the
241 MaraDNS distribution.
242 3. What license is MaraDNS released under?
244 MaraDNS is released with the following two-clause BSD-type license:
246 Copyright (c) 2002-2015 Sam Trenholme and others
248 TERMS
250 Redistribution and use in source and binary forms, with or without
252 modification, are permitted provided that the following conditions
253 are met:
254 1. Redistributions of source code must retain the above copyright
256 notice, this list of conditions and the following disclaimer.
257 2. Redistributions in binary form must reproduce the above
259 copyright notice, this list of conditions and the following
260 disclaimer in the documentation and/or other materials provided
261 with the distribution.
262 This software is provided 'as is' with no guarantees of correctness
264 or fitness for purpose.
265 4. How do I report bugs in MaraDNS?
267 Post your bug report as a Github issue.
269 5. Some of the postings to the mailing list do not talk about MaraDNS!
271 As of September 2013, the mailing list has become moderated and only
273 postings on the mailing list are relevant MaraDNS announcements.
274 6. How do I get off the mailing list?
276 Send an email to list-unsubscribe@maradns.org, or an email to list-
278 request@maradns.org with "unsubscribe" as the subject line.
279 The mailing list will send you an email confirming the unsubscribe
281 request; this email needs to be replied to in order to get off the
282 list.
283 7. How do I set up reverse DNS on MaraDNS?
285 Reverse DNS (sometimes called "reverse mapping") is set up by using PTR
287 (pointer) records. For example, the PTR record which performs the
288 reverse DNS lookup for the ip 10.2.3.4 looks like this in a CSV2 zone
289 file:
290 4.3.2.10.in-addr.arpa. PTR www.example.com.
292 It is also possible to use a special "FQDN4" which automatically sets
294 up the reverse mapping of a given record:
295 www.example.com. FQDN4 10.2.3.4
297 If you wish to have a PTR (reverse DNS lookup; getting a DNS name from
299 a numeric IP) record work on the internet at large, it is not a simple
300 matter of just adding a record like this to a MaraDNS zonefile. One
301 also needs control of the appropriate in-addr.arpa. domain.
302 While it could make logical sense to contact the IP 10.11.12.13 when
304 trying to get the reverse DNS lookup (fully qualified domain name) for
305 a given IP, DNS servers don't do this. DNS server, instead, contact the
306 root DNS servers for a given in-addr.arpa name to get the reverse DNS
307 lookup, just like they do with any other record type.
308 When an internet service provider is given a block of IPs, they are
310 also given control of the DNS zones which allow them to control reverse
311 DNS lookups for those IPs. While it is possible to obtain a domain and
312 run a DNS server without the knowledge or intervention of an ISP, being
313 able to control reverse DNS lookups for those IPs requires ISP
314 intervention.
315 8. I am on a slow network, and Deadwood can not process recursive queries
317 Deadwood, by default, only waits two seconds for a reply from a remote
319 DNS server. This default can be increased by adding a line like this in
320 the mararc file:
321 timeout_seconds = 5
323 Note that making this too high will slow MaraDNS down when DNS servers
326 are down, which is, alas, all too common on today's internet.
327 9. When I try to run MaraDNS, I get a cryptic error message.
329 There is usually some context of where there is a syntax error in a
331 data file before the cryptic error message. For example, when there is
332 a syntax error in a csv2 zone file, MaraDNS will tell you exactly at
333 what point it had to terminate parsing of the zone file.
334 If MaraDNS does return a cryptic error message without letting you know
336 what is wrong, let us know in a Github issue so that we can fix the
337 bug. MaraDNS is designed to be easy to use; cryptic error messages go
338 against this spirit.
339 10. After I start MaraDNS, I can not see the process when I run netstat
341 -na
342 Udp services do not have a prominent "LISTEN" when netstat is run.
344 When MaraDNS is up, the relevant line in the netstat output looks like
346 this: udp 0 0 127.0.0.1:53 0.0.0.0:*
347 While on the topic of netstat, if you run netstat -nap as root on Linux
349 and some other *nix operating systems, you can see the names of the
350 processes which are providing internet services.
351 11. What string library does MaraDNS use?
353 MaraDNS uses its own string library, which is called the "js_string"
355 library. Man pages for most of the functions in the js_string library
356 are in the folder doc/man of the MaraDNS distribution
357 12. Why does MaraDNS use a multi-threaded model?
359 MaraDNS 2.0 no longer uses threads.
361 It took me three years to rewrite MaraDNS' recursive resolver as a
363 separate non-threaded daemon. This has been done, and now all recursion
364 is done with Deadwood which does not need threads.
365 13. I feel that XXX feature should be added to MaraDNS
367 There are no plans to add new features to MaraDNS or Deadwood at this
369 time.
370 14. I feel that MaraDNS should use another documentation format
372 The reason that MaraDNS uses its own documentation format is to satisfy
374 both the needs of translators to have a unified document format and my
375 own need to use a documentation format that is simple enough to be
376 readily understood and which I can add features on an as needed basis.
377 The documentation format is essentially simplified HTML with some
379 special tags added to meet MaraDNS' special needs.
380 This gives me more flexibility to adapt the documentation format to
382 changing needs. For example, when someone pointed out that it's not a
383 good idea to have man pages with hi-bit characters, it was a simple
384 matter to add a new HIBIT tag which allows man pages to be without hi-
385 bit characters, and other document formats to retain hi-bit characters.
386 Having a given program have its own documentation format is not without
388 precedent; Perl uses its own "pod" documentation format.
389 15. Is there any process I need to follow to add a patch to MaraDNS?
391 I no longer accept third party patches
393 16. Can MaraDNS act as a primary nameserver?
395 Yes.
397 The zoneserver program serves zones so that other DNS servers can be
399 secondaries for zones which MaraDNS serves. This is a separate program
400 from the maradns server, which processes authoritative UDP DNS queries,
401 and Deadwood which processes recursive DNS queries.
402 See the DNS master document in the MaraDNS tutorial for details.
404 17. Can MaraDNS act as a secondary nameserver?
406 Yes.
408 Please read the DNS slave document, which is part of the MaraDNS
410 tutorial.
411 18. What is the difference between an authoritative and a recursive DNS
413 server?
414 A recursive DNS server is a DNS server that is able to contact other
416 DNS servers in order to resolve a given domain name label. This is the
417 kind of DNS server one points to in /etc/resolv.conf. MaraDNS uses the
418 Deadwood daemon to process recursive DNS queries.
419 An authoritative DNS server is a DNS server that a recursive server
421 contacts in order to find out the answer to a given DNS query. The
422 maradns daemon processes authoritative DNS queries.
423 19. The fetchzone client isn't allowing me to add certain hostnames to my
425 zone
426 For security reasons, MaraDNS' fetchzone client does not add records
428 which are not part of the zone in question. For example, if someone has
429 a zone for example.com, and this record in the zone:
430 1.1.1.10.in-addr.arpa. PTR dns.example.com.
432 MaraDNS will not add the record, since the record is out-of-bailiwick.
434 In other words, it is a host name that does not end in .example.com.
435 There are two workarounds for this issue:
437 * Create a zone file for 1.1.10.in-addr.arpa., and put the PTR records
439 there.
440 * Use rcp, rsync, or another method to copy over the zone files in
442 question.
443 20. Is MaraDNS portable?
445 MaraDNS is developed in CentOS 6 and Windows 7. MaraDNS may or may not
447 compile and run on other systems.
448 21. Can I use MaraDNS in Windows?
450 Yes. There is both a partial mingw32 (native win32 binary) port and a
452 full Cygwin port of MaraDNS; both of these ports are part of the native
453 build of MaraDNS. Deadwood has full Windows support, including the
454 ability to run as a service.
455 22. MaraDNS freezes up after being used for a while
457 If using your ISP's name servers or some other name servers which are
459 not, in fact, root name servers, please make sure that you are using
460 the upstream_servers dictionary variable instead of the root_servers
461 dictionary variable.
462 If you still see MaraDNS freeze up after making this correction, please
464 send a bug report as a Github issue.
465 23. What kind of Python integration does MaraDNS have
467 The mararc file uses the same syntax that Python uses; in fact, Python
469 can parse a properly formatted mararc file.
470 There is no other integration with Python.
472 24. Doesn't "kvar" mean "four" in Esperanto?
474 Indeed, it does. However the use of "kvar" in the MaraDNS source code
476 only coincidentally is an Esperanto word. "kvar" is short for "Kiwi
477 variable"; a lot of the parsing code comes from the code used in the
478 Kiwi spam filter project.
479 25. How scalable is MaraDNS?
481 MaraDNS is optimized for serving a small number of domains as quickly
483 as possible. That said, MaraDNS is remarkably efficnent for serving a
484 large number of domains, as long as the server MaraDNS is on has the
485 memory to fit all of the domains, and as long as the startup time for
486 loading a large number of domains can be worked around.
487 The "big-O" or "theta" growth rates for various MaraDNS functions are
489 as follows, where N is the number of authoritative host names being
490 served:
491 Startup time N
493 Memory usage N
494 Processing incoming DNS requests 1
495 As can be seen, MaraDNS will process 1 or 100000 domains in the same
497 amount of time, once the domain names are loaded in to memory.
498 26. I am having problems setting upstream_servers
500 upstream_servers is only supported by Deadwood, and is no longer
502 supported in MaraDNS 2.0. The upstream_servers dwood3rc variable is
503 set thusly:
504 upstream_servers["."] = "10.3.28.79, 10.2.19.83"
506 Note the ["."].
508 Note that the upstream_servers variable needs to be initialized before
510 being used via upstream_servers = {} (the reason for this is so that a
511 dwood3rc file has 100% Python-compatible syntax). A complete dwood3rc
512 file that uses upstream_servers may look like this:
513 ipv4_bind_addresses = "127.0.0.1"
515 chroot_dir = "/etc/maradns"
516 recursive_acl = "127.0.0.1/8"
517 upstream_servers = {}
518 upstream_servers["."] = "10.1.2.3, 10.2.4.6"
519 27. Why doesn't the MaraDNS.org web page validate?
521 HTML pages on the MaraDNS.org web site should validate as HTML 4.0
523 Transitional. However, the CSS will not validate.
524 I have designed MaraDNS' web page to be usable and as attractive as
526 possible in any major browser released in the last ten years. Cross-
527 browser support is more important than strict W3 validation. The reason
528 why the CSS does not validate is because I need a way to make sure
529 there is always a scrollbar on the web page, even if the content is not
530 big enough to merit one; this is to avoid the content jumping from page
531 to page. There is no standard CSS tag that lets me do this. I'm using a
532 non-standard tag to enable this in Gecko (Firefox's rendering engine);
533 this is enabled by default in Trident (Internet Explorer's rendering
534 engine). The standards are deficient and blind adherence to them would
535 result in an inferior web site.
536 There are also two validation warnings generated by redefinitions which
538 are needed as part of the CSS filters used to make the site attractive
539 on older browsers with limited CSS support.
540 On a related note, the reason why I use tables instead of CSS for some
542 of the layout is because Microsoft Internet Explorer 6 and other
543 browsers do not have support for the max-width CSS property. Without
544 this property, the web page will not scale down correctly without using
545 tables. Additionally, tables allow a reasonably attractive header in
546 browsers without CSS support.
547 28. How do MX records work?
549 How MX records work:
551 * The mail transport agent (Sendmail, Postfix, Qmail, MS Exchange,
553 etc.) looks up the MX record for the domain
554 * For each of the records returned, the MTA (mail transport agent)
556 looks up the IP for the names.
557 * It will choose, at random, any of the MXes with the lowest priority
559 number.
560 * Should that server fail, it will try another server with the same
562 priority number.
563 * Should all MX records with a given priority number fail, the MTA will
565 try sending email to any of the MX records with the second-lowest
566 priority value.
567 As an aside, do not have MX records point to CNAMEs.
569 29. Does MaraDNS have support for SPF?
571 SPF, or sender policy framework, is method of using DNS that makes it
573 more difficult to forge email. MaraDNS has full support for SPF, both
574 via TXT records and RFC4408 SPF records.
575 SPF configuration is beyond the scope of MaraDNS' documentation.
577 However, at the time this FAQ entry was last updated (July, 2013),
578 information and documentation concerning SPF is available at
579 http://openspf.org. The BIND examples will work in MaraDNS csv2 zone
580 files as long as the double quotes (") are replaced by single quotes
581 ('). For example, a SPF TXT record that looks like example.net. IN TXT
582 "v=spf1 +mx a:colo.example.com/28 -all" in a BIND zone file will look
583 like example.net. TXT 'v=spf1 +mx a:colo.example.com/28 -all' in a
584 MaraDNS zone file. MaraDNS can also make the corresponding SPF record,
585 which will have the syntax example.net. SPF 'v=spf1 +mx
586 a:colo.example.com/28 -all'.
587 Use '\x7e' to put a tilde ("~" character) in a SPF record:
589 example.com. SPF 'v=spf1 +mx a:colo.example.com/28 '\x7e'all'
591 30. I'm having problems resolving CNAMES I have set up.
593 This is probably because you have set up what MaraDNS calls a dangling
595 CNAME record.
596 Let us suppose we have a CNAME record without an A record in the local
598 DNS server's database, such as:
599 google.example.com. CNAME www.google.com.
601 This record, which is a CNAME record for "google.example.com", points
603 to "www.google.com". Some DNS servers will recursively look up
604 www.google.com, and render the above record like this:
605 google.example.com. CNAME www.google.com.
607 www.google.com. A 66.102.7.104
608 For security reasons, MaraDNS doesn't do this. Instead, MaraDNS will
610 simply output:
611 google.example.com. CNAME www.google.com.
613 Some stub resolvers will be unable to resolve google.example.com as a
615 consequence.
616 If you set up MaraDNS to resolve CNAMEs thusly, you will get a warning
618 in your logs about having a dangling CNAME record.
619 If you want to remove these warnings, add the following to your mararc
621 file:
622 no_cname_warnings = 1
624 Information about how to get MaraDNS to resolve dangling CNAME records
626 is in the tutorial file dangling.html
627 31. I have a NS delegation, and MaraDNS is doing strange things.
629 This is only an issue in MaraDNS 1.4. MaraDNS 2.0 does not allow the
631 same IP to both authoritatively and recursively resolve records.
632 32. I am transferring a zone from another server, but the NS records are
634 these strange "synth-ip" records.
635 MaraDNS expects, in csv2 zone files, for all delegation NS records to
637 be between the SOA record and the first non-NS record.
638 If a zone looks like this:
640 example.net. +600 soa ns1.example.net.
642 hostmaster@example.net 10 10800 3600 604800 1080
643 example.net. +600 mx 10 mail.example.net.
644 example.net. +600 a 10.2.3.5
645 example.net. +600 ns ns1.example.net.
646 example.net. +600 ns ns3.example.net.
647 mail.example.net. +600 a 10.2.3.7
648 www.example.net. +600 a 10.2.3.11
649 Then the NS records will be "synth-ip" records.
651 The zone should look like this:
653 example.net. +600 soa ns1.example.net.
655 hostmaster@example.net 10 10800 3600 604800 1080
656 example.net. +600 ns ns1.example.net.
657 example.net. +600 ns ns3.example.net.
658 example.net. +600 mx 10 mail.example.net.
659 example.net. +600 a 10.2.3.5
660 mail.example.net. +600 a 10.2.3.7
661 www.example.net. +600 a 10.2.3.11
662 This will remove the "synth-ip" records.
664 To automate this process, this awk script is useful:
666 fetchzone whatever.zone.foo 10.1.2.3 | awk '
668 {if($3 ~ /ns/ || $3 ~ /soa/){print}
669 else{a = a "\n" $0}}
670 END{print a}' > zonefile.csv2
671 Replace "whatever.zone.foo" with the name of the zone you are fetchin
673 10.1.2.3 with the IP address of the DNS master, and zonefile.csv2 with
674 the name of the zone file MaraDNS loads.
675 33. Where is the root.hints file?
677 MaraDNS (actually, Deadwood), unlike BIND, does not need a complicated
679 root.hints file in order to have custom root servers. In order to
680 change the root.hints file, add something like this to your dwood3rc
681 file:
682 root_servers["."] = "131.161.247.232,"
684 root_servers["."] += "208.185.249.250,"
685 root_servers["."] += "66.227.42.140,"
686 root_servers["."] += "66.227.42.149,"
687 root_servers["."] += "65.243.92.254"
688 Note that there is no "+=" in the first line, and the last line does
690 not have a comma at the end. Read the recursive tutorial document for
691 more information.
692 34. Are there any plans to use autoconf to build MaraDNS?
694 No.
696 In more detail, MaraDNS does not use autoconf for the following
698 reasons:
699 * Autoconf is designed to solve a problem that existed in the mid 1990s
701 but does not exist today: A large number of different incompatible C
702 compilers and libc implementations. These days, most systems are
703 using gcc as the compiler and some version of glibc as the libc.
704 There is no longer a need, for example, to figure out whether a given
705 implementation of getopt() allows '--' options. MaraDNS's
706 ./configure script can be run in only a second or two; compare this
707 to the 3-5 minute process autoconf's ./configure needs.
708 * Autoconf leaves GPL-tained files in a program's build tree. MaraDNS
710 is licensed under a BSD license that is not GPL-compatible, so
711 MaraDNS can not be distributed with these GPL-licensed files.
712 This leads us to the next question:
714 35. How do I change the compiler or compile-time flags with MaraDNS' build
716 process?
717 To change the compiler used by MaraDNS:
719 * Run the ./configure script
721 * Open up the file Makefile with an editor
723 * Look for a line that starts with CC
725 * If there is no line that starts with CC, create one just before the
727 line that starts with FLAGS
728 * Change (or create) that line to look something like CC=gcc296 In this
730 example, the 2.96 version of gcc is used to compile MaraDNS.
731 * Note that it is important to not remove anything from this line you
733 do not understand; doing so will make MaraDNS unable to compile or
734 run. So, if the CC line looks like
735 CC=gcc $(LDFLAGS) -DNO_FLOCK and you want to compile with
736 gcc 2.96, change the line to look like
737 CC=gcc296 $(LDFLAGS) -DNO_FLOCK retaining the flags added
738 by the configuration script.
739 Changing compile-time flags is a similar process:
741 * Run the ./configure script
743 * Open up the file Makefile with an editor
745 * Look for a line that starts with FLAGS
747 * Change (or create) that line to look something like FLAGS=-O3 In this
749 example, MaraDNS is compiled with the -O3 option.
750 * Note that it is important to not remove anything from this line you
752 do not understand; doing so will make MaraDNS unable to compile or
753 run. So, if the FLAGS line looks like
754 FLAGS=-O2 -Wall -DSELECT_PROBLEM and you want to compile at
755 optimization level three, change this line to look like
756 FLAGS=-O2 -Wall -DSELECT_PROBLEM retaining the flags added
757 by the configuration script. -DSELECT_PROBLEM for example, is needed
758 in the Linux compile or MaraDNS will have problems with freezing up.
759 36. Will you make a package for the particular Linux distribution I am
761 using?
762 No.
764 There is, however, a CentOS 5-compatible RPM spec file in the build
766 directory.
767 37. I am using the native Windows port of MaraDNS, and some features are
769 not working.
770 Since Windows 32 does not have some features that *NIX OSes have, the
772 native Windows port does not have all of the features of the *NIX
773 version of MaraDNS. In particular, the following features are disabled:
774 * ipv6 (this is actually a mingw32, not a Windows deficiency)
776 * The chroot_dir mararc variable
778 * The maradns_gid and maradns_uid mararc variables
780 * The maxprocs mararc variable
782 * The synth_soa_serial variable can not have a value of 2
784 * There is no DNS-over-TCP support
786 If any of the above features are desired, try compiling MaraDNS using
788 Cygwin. Note that the Cygwin port of MaraDNS does not have ipv6
789 support, and that while chroot_dir works in Cygwin, it does not have
790 the security that the *NIX chroot() call has.
791 38. MaraDNS isn't starting up
793 This is usually caused by a syntax error in one's mararc file, or by
795 another MaraDNS process already running. To see what is happening, look
796 at your system log (/var/log/messages in Centos 3) to see what errors
797 MaraDNS reports. If you do not know how to look at a system log, you
798 can also invoke MaraDNS from the command line as root; any errors will
799 be visible when starting MaraDNS.
800 39. You make a lot of releases of MaraDNS; at our ISP/IT department,
802 updating software is non-trivial.
803 Regularly updating software is required to keep something as
805 complicated as a DNS server secure; there is not a DNS server out there
806 so secure that it never needs to be updated.
807 Since MaraDNS is finished, updates usually only happen about once a
809 year.
810 The last security bug which required a MaraDNS update was made before
812 January 30, 2015.
813 40. I have star records in my zones, and am having problems with
815 NXDOMAINs/IPV6 resolution
816 This was a bug in MaraDNS 1.2 which has long since been fixed.
818 41. I have a zone with only SOA/NS records, and the zone is not working.
820 MaraDNS 1.2 had a bug where it did not correctly process zones without
822 any "normal" records. Upgrade to MaraDNS 2.0.
823 42. I am having problems registering my domain with AFNIC (the registrar
825 for .fr domains)
826 Because of an issue with AFNIC (who, annoyingly enough, check the RA
828 bit when registering a domain), in order to register a domain with
829 AFNIC using MaraDNS as your DNS server, the following steps need to be
830 followed:
831 * MaraDNS version 1.4 or 2.0 needs to be used; if you're using an older
833 version of MaraDNS, upgrade.
834 * It is necessary to have recursion disabled, if using MaraDNS 1.4,
836 either by compiling MaraDNS without recursive support (./configure
837 --authonly ; make), or by making sure MaraDNS does not have recursion
838 enabled (by not having recursive_acl set in one's MaraDNS 1.4 mararc
839 file)
840 If one wishes to both register domains with AFNIC and use MaraDNS 1.4
842 as a recursive DNS server, it is required to have the recursive server
843 be a separate instance of MaraDNS on a separate IP. It is not possible
844 to have the same DNS server both send DNS packets in a way that both
845 makes AFNIC happy and allows recursive queries.
846 Note also: AFNIC gives warnings about reverse DNS lookups; more
848 information about this issue can be found in the FAQ entry about
849 reverse DNS mappings (question 7). In addition, AFNIC requires DNS-
850 over-TCP to work; information on configuring MaraDNS to have this can
851 be found in the DNS-over-TCP tutorial.
852 43. I can't see the full answers for subdomains I have delegated
854 To have the subdomains be visible to MaraDNS 1.4 recursive nameservers,
856 add the following to your mararc file:
857 recurse_delegation = 1
859 44. MaraDNS 1 has a problem resolving a domain
861 This issue should be fixed in MaraDNS 2.0.
863 Here's what happening: I have rewritten the recursive resolver for
865 MaraDNS. The old code was always designed to be a placeholder until I
866 wrote a new recursive resolver.
867 The new recursive resolver is called "Deadwood"; right now it's fully
869 functional and part of MaraDNS 2.0. More information is here:
870 http://maradns.blogspot.com/search/label/Deadwood
872 http://maradns.samiam.org/deadwood/
874 Since the old recursive code is a bit difficult to maintain, and since
876 I in the process of rewriting the recursive code, my rule is that I
877 will only resolve security issues with MaraDNS 1.0's recursive
878 resolver.
879 45. MaraDNS 1.2 had issues with NXDOMAINS and case sensitivity.
881 There was a known bug in MaraDNS 1.2.12 where, should a client ask for
883 a non-existent record in all caps, MaraDNS 1.2.12 will return a
884 NXDOMAIN instead of a "not there" reply. Upgrade to 2.0.
885 46. Can MaraDNS offer protection from phishing and malicious sites?
887 Deadwood can block up to about 20,000 domains. More details are in the
889 Deadwood FAQ.
890 47. Does maradns support star (wildcard) records?
892 Yes.
894 MaraDNS supports both having stars at the beginning of records and the
896 end of records. For example, to have anything.example.com. have the IP
897 10.1.2.3, add this line to the zone file for example.com:
898 *.example.com. A 10.1.2.3
900 To have stars at the end of records, csv2_default_zonefile has to be
902 set. The mararc parameter bind_star_handling affects how star records
903 are handled. More information is in the mararc man page.
904 48. I'm having problems using MaraDNS with some *NIX command line
906 applications like telnet.
907 Some *NIX command line networking applications, such as telnet and ssh,
909 try to do either a reverse DNS lookup (IP-to-host name conversion) or
910 an IPv6 lookup. This slows things down and sometimes causes the
911 applications to not work at all.
912 For people who do not need IPv6 lookups, add the following line to
914 one's mararc file to have MaraDNS respond to all IPv6 lookups with a
915 bogus "not found" reply:
916 reject_aaaa = 1
918 If knowing the hostname a given IP has isn't important, these kinds of
920 lookups can also be disabled:
921 reject_ptr = 1
923 49. My virus scanner reports that MaraDNS or Deadwood has a virus
925 This can be caused either by a poorly written anti-virus program
927 reporting a false positive, or because a virus on your system has
928 infected your copy of MaraDNS/Deadwood.
929 Please use GPG to verify that the file which your scanner reports
931 having a virus in has not been altered. In addition, please scan the
932 file with AVG (free for non-commercial use) to verify your virus
933 scanner has not reported a false positive.
934 If you have verified the GPG signature of the program and AVG reports a
936 virus, please let us know with a Github issue. Otherwise, please use a
937 better virus scanner and make sure there are no viruses on your
938 computer.
939 50. I can not subscribe to the MaraDNS mailing list
941 Please note that the mailing list is no longer used to handle MaraDNS
943 support requests. Please file a Github issue at
944 https://github.com/samboy/MaraDNS/issues to file a MaraDNS bug report.
945 The procedure for subscribing to the mailing list is as follows:
947 * Send an email to list-request@maradns.org with "Subscribe" as the
949 subject, or an email to list-subscribe@maradns.org
950 * You will get an email from list-request@maradns.org asking you to
952 confirm your subscription. This can be done by replying to the
953 message, or, more simply, by clicking on the link in the message.
954 * Once you click on that link, click on the button marked "subscribe to
956 list list"
957 * You will now get a message stating 'Welcome to the "list" mailing
959 list'.
960 * Note that the mailing list is moderated and only relevant MaraDNS
962 announcements are approved. People who need help should read the
963 manuals or search the MaraDNS webpage for support.
964 If you get an email from list-request@maradns.org with the subject "The
966 results of your email commands", you did not correctly send an email to
967 list-request@maradns.org with the subject "Subscribe".
968 If you do not get the email from list-request@maradns.org asking you
970 for a confirmation, ensure that this email is not in your "spam" or
971 "junk mail" folder. If you are unable to get these emails at your email
972 address, please get a gmail email account, which can successfully
973 subscribe to the MaraDNS mailing list. Note that subscription
974 confirmation emails may be in Gmail's "promotions" tab.
975 51. How does MaraDNS respond to EDNS (RFC2671) packets?
977 MaraDNS 2 (both the authoritative maradns server and the recursive
979 Deadwood server) responds to EDNS packets by ignoring the OPT record
980 and acting as if it the packet did not have an OPT record.
981 MicroDNS (available in the tools/misc directory of any MaraDNS 2
983 release) responds to EDNS queries the same way Deadwood 2.9.03 did: By
984 giving back "NOTIMPL" instead of answering the query with the default
985 IP. NanoDNS, in the interest of minimizing code side, responds to EDNS
986 requests by returning NOTIMPL in the header, giving the OPT query in
987 the AN section of the response, and giving the default IP in the AR
988 section of the DNS reply packet.
989 52. How to I get MaraDNS to always give the same IP to all DNS queries?
991 There are three ways to have MaraDNS always give the same IP in reply
993 to any DNS query given to it:
994 * The best way to do this is to set up a default zonefile that causes
996 any and all A queries to always give the IP (and also allows all AAAA
997 queries to always give out the same IP6, all SPF or TXT queries to
998 give out the same SPF record, etc.).
999 * Another possibility, if someone just wants a simple DNS server that
1001 always gives out the same IP address to any and all DNS queries, is
1002 to use the MicroDNS program, available in tools/misc, as well as
1003 having its own web page.
1004 * If MicroDNS is too bloated, there is also NanoDNS, which I will
1006 include the source code of below:
1007 /*Placed in the public domain by Sam Trenholme*/
1009 #include <arpa/inet.h>
1010 #include <string.h>
1011 #include <stdint.h>
1012 #define Z struct sockaddr
1013 #define Y sizeof(d)
1014 int main(int a,char **b){uint32_t i;char q[512]
1015 ,p[17]="\xc0\f\0\x01\0\x01\0\0\0\0\0\x04";if(a>
1016 1){struct sockaddr_in d;socklen_t f=511;bzero(&
1017 d,Y);a=socket(AF_INET,SOCK_DGRAM,0);*((uint32_t
1018 *)(p+12))=inet_addr(b[1]);d.sin_family=AF_INET;
1019 d.sin_port=htons(53);bind(a,(Z*)&d,Y);for(;;){i
1020 =recvfrom(a,q,255,0,(Z*)&d,&f);if(i>9&&q[2]>=0)
1021 {q[2]|=128;q[11]?q[3]|=4:1;q[7]++;memcpy(q+i,p,
1022 16);sendto(a,q,i+16,0,(Z*)&d,Y);}}}return 0;}
1023 NanoDNS takes one argument: The IP we return. This program binds to all
1025 IP addresses a given machine has on the UDP DNS port (port 53). For
1026 example, to make a DNS server that binds to all IPs your system has and
1027 return the IP 10.11.12.13 to any UDP DNS queries sent to it, compile
1028 the above C program, call it NanoDNS, and invoke it with NanoDNS
1029 10.11.12.13 Note that NanoDNS does not daemonize, nor log anything, nor
1030 have any other space-wasting features.
1031 Why did you change MaraDNS' tagline?
1033 I have changed MaraDNS' tagline from "MaraDNS: A security-aware DNS
1035 server" to "MaraDNS: A small open-source DNS server" because MaraDNS
1036 does not support DNSSEC. I have blogged about this:
1037 http://samiam.org/blog/20120326.html
1039 How do you stop MaraDNS from taking part in a distributed denial-of-
1041 service attack?
1042 While I do not have time to implement rate limiting, CentOS 6 does
1044 support response rate limiting at the firewall level. The following
1045 iptables commands allow a given IP to only send MaraDNS/Deadwood 20 DNS
1046 queries every four seconds:
1047 iptables -A INPUT -p udp --dport 53 -m state --state NEW -m recent
1049 --set --name DDOS --rsource
1050 iptables -A INPUT -p udp --dport 53 -m state --state NEW -m recent
1052 --update --seconds 4 --hitcount 20 --name DDOS --rsource -j DROP
1053 To verify they are applied:
1055 iptables --list
1057 To save these commands in CentOS so they are applied at system boot
1059 time:
1060 iptables-save > /etc/sysconfig/iptables
1062 Disclaimer
1064 These incantations work in CentOS 6 but may or may not work in other
1066 versions of Linux. I do not support non-CentOS6 Linux installs of
1067 MaraDNS.
1068 What about DNS-over-TCP?
1070 For people who want DNS-over-TCP, instructions are in the DNS-over-TCP
1072 tutorial. Note that Windows users will have to use Cygwin to have DNS-
1073 over-TCP.
1074 However, DNS-over-TCP is not necessary. DNS-over-TCP is optional as per
1076 section 6.1.3.2 of RFC1123; any program or web service that considers
1077 no DNS-over-TCP an error is not RFC-compliant.
1078 Not having DNS-over-TCP is more secure, because it gives attackers a
1080 smaller surface to attack.
1081 How do I use MaraDNS with systemd?
1083 While I like systemd, it is not part of CentOS 6 nor, obviously,
1085 Windows 7. That in mind, I have no plans to support systemd until 2017,
1086 when I plan to update MaraDNS' supported operating systems.
1087 However, Tomasz Torcz has kindly made some systemd files for MaraDNS,
1089 which people are free to use.
1090 As an aside, I do not like the fact that Debian will probably not make
1092 systemd the default init; I do not think this kind of fragmentation is
1093 good for Linux.
1094 Why doesn't MaraDNS use IP_FREEBIND?
1096 IP_FREEBIND is a non-POSIX Linux-specific extension to POSIX's
1098 netinet/in.h, and, as such, has no place in MaraDNS' code. MaraDNS
1099 strives to use POSIX-compliant calls so that it can compile on as many
1100 systems as possible.
1101 When I say that Windows 7 and CentOS 6 are the only supported operating
1103 systems for MaraDNS, this does not mean that MaraDNS will not compile
1104 and run on other systems; it merely means that I can not provide
1105 support for Github bug reports for people who want to run MaraDNS in
1106 Minix, one of the open-source BSD variants, or what not.
1107 Is there a web interface for MaraDNS?
1109 The Kloxo-MR control panel has MaraDNS support.
1111 What does the message “don’t forget the trailing dot” mean?
1113 It means to not forget the tailing dot.
1115 Hostnames in zone files need to be properly terminated; if a hostname
1117 is in the form “foo.example.com”, this name will not parse and return
1118 an error with a note to not forget the trailing dot.
1119 To fix this, put a trailing dot at the end of the hostname, so it looks
1121 like “foo.example.com.” (observe that dot at the end) instead of
1122 “foo.example.com”
1123 Does MaraDNS support newer top level domains?
1125 MaraDNS does not impose any limitations on the top level domain used in
1127 zone files and other places, as is fully compatible with newer top
1128 level domains like “today.”
1129 Note that, if using an internationalized domain name, it needs to be
1131 translated in to Punycode first. For example, if using the domain name
1132 “ñ.com.”, it needs to be in the form “xn--ida.com.” in MaraDNS’ mararc
1133 and zone files.
1134
1136 In the unusual case of having a csv2 zone file with Macintosh-style
1137 newlines (as opposed to DOS or UNIX newlines), while the file will
1138 parse, any errors in the file will be reported as being on line 1.
1139 The system startup script included with MaraDNS assumes that the only
1141 MaraDNS processes running are started by the script; it stops all
1142 MaraDNS processes running on the server when asked to stop MaraDNS.
1143 MaraDNS needs to use the zoneserver program to serve DNS records over
1145 TCP. See zoneserver(8) for usage information.
1146 MaraDNS does not use the zone file ("master file") format specified in
1148 chapter 5 of RFC1035; however bind2csv2.py can convert the majority of
1149 such zone files.
1150 MaraDNS default behavior with star records is not RFC-compliant. In
1152 more detail, if a wildcard MX record exists in the form
1153 "*.example.com", and there is an A record for "www.example.com", but no
1154 MX record for "www.example.com", the correct behavior (based on RFC1034
1155 section 4.3.3) is to return "no host" (nothing in the answer section,
1156 SOA in the authority section, 0 result code) for a MX request to
1157 "www.example.com". Instead, MaraDNS returns the MX record attached to
1158 "*.example.com". This can be changed by setting bind_star_handling to
1159 1.
1160 Star records (what RFC1034 calls "wildcards") can not be attached to NS
1162 records.
1163 MaraDNS, like every other known DNS implementation, only supports a
1165 QDCOUNT of 0 or 1.
1166
1168 These are features which I do not plan to implement in MaraDNS.
1169 MaraDNS does not have a disk-based caching scheme for authoritative
1171 zones.
1172 MaraDNS' UDP server only loads zone files while MaraDNS is first
1174 started. UDP Zone information can only be updated by stopping MaraDNS,
1175 and restarting MaraDNS again. Note that TCP zone files are loaded from
1176 the filesystem at the time the client requests a zone.
1177 MaraDNS does not have support for allowing given host names to only
1179 resolve for a limited range of IPs querying the DNS server, or for host
1180 names to resolve differently, depending on the IP querying the host
1181 name.
1182 MaraDNS only allows wildcards at the beginning or end of a host name.
1184 E.g. names with wildcards like "foo.*.example.com". "www.*" will work,
1185 however, if a default zonefile is set up. Likewise, MaraDNS does not
1186 have regular expression hostname substitution.
1187 MaraDNS does not have support for MRTG or any other SNMP-based logging
1189 mechanism.
1190
1192 THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY EXPRESS OR
1193 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
1194 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
1195 DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
1196 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
1197 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
1198 OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
1199 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
1200 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
1201 IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1202 POSSIBILITY OF SUCH DAMAGE.
1203
1205 Sam Trenholme (http://www.samiam.org) is responsible for this man page.
1206 MaraDNS is written by me, Sam Trenholme, with a little help from my
1208 friends. Naturally, all errors in MaraDNS are my own (but read the
1209 disclaimer above).
1210 Here is a partial list of people who have provided assistance:
1212 Floh has generously set up a FreeBSD 4, FreeBSD 6, and Mac OS X system
1214 so that I can port MaraDNS to more platforms.
1215 Albert Lee has provided countless bug reports, and, nicely enough,
1217 patches to fix said bugs. He has also made improvements to the code in
1218 the tcp "zoneserver".
1219 Franky Van Liedekerke has provided much invaluable assistance. As just
1221 one example, he provided invaluable assistance in getting MaraDNS to
1222 compile on Solaris. In addition, he has provided much valuable SQA
1223 help.
1224 Christian Kurz, who has provided invaluable bug reports, especially
1226 when I had to re-implement the core hashing algorithm.
1227 Remmy, who is providing both the web space and a mailing list for
1229 maradns.org.
1230 Phil Homewood, who provided invaluable assistance with finding and
1232 fixing bugs in the authoritative portion of the MaraDNS server. He
1233 helped me plug memory leaks, find uninitialized variables being used,
1234 and found a number of bugs I was unable to find.
1235 Albert Prats kindly provided Spanish translations for various text
1237 files.
1238 Shin Zukeran provided a patch to recursive.c which properly makes a
1240 normal null-terminated string from a js_string object, to send as an
1241 argument to open() so we can get the rijndael key for the PRNG.
1242 D Richard Felker III has provided invaluable bug reports. By looking at
1244 his bug reports, I have been able to hunt down and fix many problems
1245 that the recursive nameserver had, in addition to at least one problem
1246 with the authoritative nameserver.
1247 Ole Tange has also given me many valuable MaraDNS bug reports.
1249 Florin Iucha provided a tip in the FAQ for how to compile MaraDNS on
1251 OpenBSD.
1252 Roy Arends (one of the BIND developers, as it turns out) found a
1254 serious security problem with MaraDNS, where MaraDNS would answer
1255 answers, and pointed it out to me.
1256 Code used as the basis for the psudo-random-number generator was
1258 written by Vincent Rijmen, Antoon Bosselaers, and Paulo Barreto. I
1259 appreciate these programmers making the code public domain, which is
1260 the only license under which I can add code to MaraDNS under.
1261 Ross Johnson and others have made a Win32 port of the Pthreads library;
1263 this has made a native win32 port of MaraDNS possible.
1264 I also appreciate the work of Dr. Brian Gladman and Fritz Schneider,
1266 who have both written independent implementations of AES from which I
1267 obtained test vectors. With the help of their hard work, I was able to
1268 discover a subtle security problem that previous releases of MaraDNS
1269 had.
1270MARADNS January 2002 MARADNS(8)