FREQUENTLY ASKED QUESTIONS
INDEX
1. I'm still using version 1.0 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
ANSWERS
1. I'm still using version 1.0 of MaraDNS
MaraDNS 1.0 will continue to be fully supported until December 21, 2007; this
means that MaraDNS 1.0 questions will still be answered and bug fixes will
still be applied. After 2007/12/21, MaraDNS 1.0 will no longer be fully
supported; the only updates, at that point, would be bugtraq-worthy critical
security fixes. Not even these security updates will be applied after
December 21, 2010.
People who wish to run MaraDNS 1.0 unsupported after 2010/12/21 need to keep
in mind that MaraDNS 1.0 is not Y2038 compliant, and will have
problems starting in 2036 or so. MaraDNS 1.2, on the other hand, is fully
Y2038 compliant.
There is still a FAQ for version 1.0 of MaraDNS available
here.
Updating from 1.0 to 1.2 requires a minimum number of changes; with most
configurations, MaraDNS 1.2 is fully compatible with MaraDNS 1.0 data
files. Details are in the updating document
in the tutorial.
While csv1 zone files are fully supported in MaraDNS 1.2, there is a Perl
script for updating from CSV1 to CSV2 zone files in the tools/
directory of MaraDNS 1.2.
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 1.2 is released with the following two-clause BSD license:
BSD-type license:
Copyright (c) 2002-2005 Sam Trenholme
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?
Please
contact me.
5. Some of the postings to the mailing list do not talk about MaraDNS!
In cases where I post something to the mailing list which does not directly
talk about MaraDNS, the subject line will not have [MARA] in it, but will
have some form of the word CHATTER in it.
This way, people who do not like this can set up mail filters to filter out
anything that comes from this list and doesn't have [MARA] in the subject
line, or simply unsubscribe from the list and read the list from the
archives; if one needs to report a bug, they can subscribe to the list
again, post their bug, then unsubscribe after a week.
Another option is to set up one's Freshmeat preferences to be notified
in email every time I update MaraDNS at Freshmeat. This will give one
email notice of any critical bug fixes without needing to be
subscribed to the mailing list.
The web page http://www.maradns.org/
has a link to the mailing list archives.
6. How do I get off the mailing list?
Send an email to list-request@maradns.org with "unsubscribe" as the
subject line.
7. How do I set up reverse DNS on MaraDNS?
By using PTR (pointer) records. For example, the PTR record which performs
the reverse DNS lookup for the ip 1.2.3.4 looks like this in a CSV2 zone
file:
4.3.2.1.in-addr.arpa. PTR www.example.com.
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 can 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 MaraDNS can not process recursive
queries
MaraDNS, 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 me know
so that I 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?
The multi-threaded model is, plain and simple, the simplest way to write
a functioning recursive DNS server. There is a reason why MaraDNS, pdnsd, and
BIND 9 all use the multi-threaded model.
13. I feel that XXX feature should be added to MaraDNS
There are currently no plans to implement new features in MaraDNS. The
reason for this is because, bottom line, MaraDNS has failed to make my
resume impressive enough for me to easily get a job in today's job
market.
Both the BIND and NSD name servers were developed by having the programmers
paid to work on the programs. PowerDNS was originally commercial software
with the author only reluctantly made GPL after seeing that the market
for a commercial DNS server is very small. All of the other DNS servers
which have been developed as hobbyist projects (Posadis, Pdnsd, and djbdns)
are no longer being actively worked on by the primary developer.
If I were to work on MaraDNS again, it will be a complete rewrite in C++;
if I can get C++ on my resume, I may be able to get a job more easily.
Like anything else, this is not absolute. For example, if I see a large
MaraDNS community and a strong demand for new features from that community,
I will change my mind. Should ipv6 start to become dominant, I will update
MaraDNS to have full ipv6 support. Should some other technology come along
that will require an update to MaraDNS for MaraDNS to continue to function
as a DNS server, I may update MaraDNS to use that technology.
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?
Yes.
Here is the procedure for making a proper patch:
- Enter the directory that the file is in, for example
maradns-1.2.00/server
- Copy over the file that you wish to modify to another file
name. For example: cp MaraDNS.c MaraDNS.c.orig
- Edit the file in question, e.g: vi MaraDNS.c
- After editing, do something like this:
diff -u MaraDNS.c.orig MaraDNS.c > maradns.patch
- Make sure the modified version compiles cleanly
Send a patch to me in email, along with a statement that you place
the contents of the patch under MaraDNS' BSD license. If I find that the patch
works well, I will integrate it in to MaraDNS.
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 both
authoritative and recursive UDP 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/resolve.conf
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.
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 will only compile on FreeBSD, Mac OS X, Cygwin, Linux, and
partially on MinGW32 systems. If you are interested in porting MaraDNS
to another system, please let me know.
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.
22. MaraDNS freezes up after being used for a while
If you are using MaraDNS 1.2.03.1 (or any 1.1 release, for that matter) on
Linux, upgrade to version 1.2.03.2. There is a bug with the Linux kernel
which causes UDP clients to freeze unless code is written to work around
the kernel bug. This workaround was first introduced in MaraDNS 1.0.28
and 1.1.35 and accidently disabled in 1.2.03.1.
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 to the mailing list.
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 currently 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
The upstream_servers mararc variable is set thusly:
upstream_servers["."] = "10.3.28.79, 10.2.19.83"
Note the
["."]. The reason for this is so future versions
of MaraDNS may have more fine-grained control over the
upstream_servers and
root_servers values.
Note that the upstream_servers variable needs to be initialized
before being used via upstream_servers = {} (the reason for this
is so that a mararc file has 100% Python-compatible syntax). A complete
mararc 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"