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mararc - Man Page

Format of the mararc zone file that MaraDNS uses


Mararc File Format

Mararc files use a syntax that is a subset of Python 2.2.3 syntax. In  particular, Python 2.2.3 (and possibly other versions of Python) can  read a properly formatted mararc file without error.

Unlike Python, however, a mararc file can only use certain variable  names, and the variables can only be declared as described below.


Comments (lines ignored by the MaraDNS parser) start with the '#'  character, like this:

# This is a comment

The MaraDNS parser also ignores lines which contain only white space.


The MaraRC file supports two operators: = and +=

The = operator can be used to assign both numeric and string values

The += operator can only be used on string values, and concatenates the  value to the right of the += operator to the string specified to the  left of the += operator.


ipv4_bind_addresses = "" 
ipv4_bind_addresses += "," 
ipv4_bind_addresses += ","

ipv4_bind_addresses now has the value  ",,"

ipv4_alias["icann"] = "" 
ipv4_alias["icann"] += "," 
ipv4_alias["icann"] += ",,"

Mararc Variables

Follows is a listing of variables that can be declared in the mararc  file.

Dictionary Variable Format

A dictionary variable is an array that can have multiple elements. Unlike a traditional  array, these arrays are indexed by strings instead of numbers. These  are analogous to associative arrays, or what Perl somewhat inaccurately  calls hashes.

The syntax of a dictionary variable is in the following form:

name["index"] = "value"

Where name is the name of the dictionary variable, index is the index of the array, and value is the value stored at that index.

Every time we have a dictionary-type variable (such as csv2), we must  first initialize it using a line in the following form:

csv2 = {}

Here, csv2 is the name of the "dictionary" variable that we are  initializing.

Dictionary Variables

Here is a listing of all "dictionary"-style variables that MaraDNS  uses:


The csv2 dictionary variable stores all of the zone names and file  names for the zone files that MaraDNS uses. Note that csv2 files are  read after MaraDNS is chrooted. Hence the filename is relative to the  chroot_dir. Example:

csv2["example.net."] = "db.example.net"

See csv2(5) for a description of this file's format.

The dictionary index (zone name) can not have a * in it. If it does,  MaraDNS will terminate with an "Illegal zone name" error.

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.


csv1: Used to indicate the filename to use for a given zone stored in  the legacy csv1 zone file format. This is primarily for compatibility  with people who have maradns-1.0 zone files.

csv1["zone"] = "filename"

csv1: A pipe-separated-file. See csv1(5).

zone: the zone that file in question is authoritative for

filename: the file with the CSV1 zone data

Note that csv1 files are read after MaraDNS is chrooted, and, hence the  filename is relative to the chroot_dir.

See the csv1(5) man page for more information on this file format.


ipv4_alias: Used to give nicknames or aliases for ip/netmask pairs for  ipv4 (standard 32-bit) IP addresses.

ipv4_alias["name"] = "ip1/netmask,ip2/netmask,etc"

name: The name of the alias in question

ip: The ip portion of an ip/netmask pair

netmask: the mask portion of an ip/netmask pair

,: Used to separate ip/netmask pairs. Spaces may be placed before or after  this comma.

An ip is in dotted-decimal format, e.g. "".

The netmask can be in one of two formats: A single number between 1 and  32, which indicates the number of leading "1" bits in the netmask, or a  4-digit dotted-decimal netmask.

The netmask is used to specify a range of IPs.

ipv4_alias examples indicates that any ip from to will match. is identical to indicates that any ip from to will match. is identical to indicates that any ip with "127" as the first octet (number) will  match. is identical to

The netmask is optional, and, if not present, indicates that only a  single IP will "match". e.g:,, and are all functionally identical, and indicate that only the ip  will match.

The significance of "match" depends on what we use the ipv4 alias for.

ipv4 aliases can nest. E.g:

ipv4_alias["susan"] = ""  
ipv4_alias["office"] = "susan,"

Where "susan" in the "office" alias matches the value of the ipv4_alias  susan.

Multiple levels of nesting are allowed. Self-referring nests will  result in an error.

Normal Variable Format

Normal variables. These are variables that can only take a single  value.

The syntax of a normal variable is in the form

name = "value"

Where name is the name of the normal variable, and value is the value of the variable in question.

Normal Variables

Here is a listing of normal variables that MaraDNS uses:


ipv4_bind_addresses: The IP addresses to give the MaraDNS server.

This accepts one or more ipv4 IPs in dotted-decimal (e.g. "")  notation, and specifies what IP addresses the MaraDNS server will  listen on. Multiple bind addresses are separated with a comma, like  this: ",,"


This is a list of ip/netmask pairs that are allowed to get certain  administrative information about MaraDNS, including:  

Note that this information is not available unless the mararc variable  debug_msg_level is sufficiently high. See the information on  debug_msg_level below for details on this and on the TXT queries sent  to get the above information.


bind_address: The IP address to give the MaraDNS server.

This accepts a single IP in dotted-decimal (e.g. "") notation,  and specifies what IP address the MaraDNS server will listen on. Note  that ipv4_bind_addresses has the same functionality. This name is  included so that old MaraDNS configuration files will continue to work  with new MaraDNS releases.


In the case where there is both a star record for a given name and  recordtype, a non-star record with the same name but a different  recordtype, and no record for the given name and recordtype, MaraDNS  will usually return the star record. BIND, on the other hand, will  return a "not there" reply. In other words:  

If the BIND behavior is desired, set bind_star_handling to 1.  Otherwise, set this to 0. In MaraDNS 1.3, this has a default value of  1.

In addition, if there is a star record that could match any given  record type, when bind_star_handling is 1, it makes sure that MaraDNS  does not incorrectly return a NXDOMAIN (RFC 4074 section 4.2).

Also, if bind_star_handling has a value of 2, MaraDNS will handle the  following case exactly as per section 4.3.3 of RFC1034:  

MaraDNS will exit with a fatal error if bind_star_handling has any  value besides 0, 1, or 2.


chroot_dir: The directory MaraDNS chroots to

This accepts a single value: The full path to the directory to use as a  chroot jail.

Note that csv1 zone files are read after the chroot operation. Hence,  the chroot jail needs to have any and all zone files that MaraDNS will  load.


This is a special zone file that allows there to be stars at the end of hostnames. This file is similar to a normal csv2 zone file, but has  the following features and limitations:  


Sometimes the IP list of nameservers will be different than the  nameservers one is bound to. This allows the synthetic nameserver list  to have different IPs.

Note that this may act in an unexpected manner if routable and  non-routable (localhost and RFC1918) addresses are combined; in  particular, a list with both routable and non-routable addresses will  discard the non-routable IP addresses, and a list with rfc1918 and  localhost addresses will discard the localhost addresses.


How the csv2 zone file parser handles tildes (the ~ character) in csv2  zone files. This is a numeric record, with a possible value between 0  and 3 (four possible values). The way the csv2 parser acts at different  csv2_tilde_handling levels:  

The default value for csv2_tilde_handling is 2; this allows  compatibility with older zone files without tildes while allowing zone  files to be updated to use the tilde to separate resource records.


This is a number indicating what level of information about a running  MaraDNS process should be made public. When set to 0, no information  will be made public.

When set to one (the default), or higher, a Tversion.maradns. (TXT  query for "version.maradns.") query will return the version number of  MaraDNS.

When set to two or higher, a Tnumthreads.maradns. (TXT query for  "numthreads.maradns.") query will return the number of threads that  MaraDNS is currently running, and a Tcache-elements.maradns. query will  return the number of elements in MaraDNS' cache.

If MaraDNS is compiled with debugging information on, a  Tmemusage.maradns. query will return the amount of memory MaraDNS has  allocated. Note that the overhead for tracking memory usage is  considerable and that compiling MaraDNS with "make debug" will greatly  slow down MaraDNS. A debug build of MaraDNS is not recommended for production use.

When set to three or higher, a Ttimestamp.maradns. query will return,  in seconds since the UNIX epoch, the timestamp for the system MaraDNS  is running on.


This variable used to determine what kind of resource records were  returned when an ANY query was sent. In MaraDNS, the data structures  have since been revised to return any resource record type when an ANY  query is sent; this variable does nothing, and is only here so that old  MaraDNS mararc files will continue to work. The only accepted values  for this variable were 3 and 15.


This is the port that MaraDNS listens on. This is usually 53 (the  default value), but certain unusual MaraDNS setups (such as when  resolving dangling CNAME records on but a single IP) may need to have a  different value for this.


If this is set to a non-zero value, certain features of MaraDNS will be  disabled in order to speed up MaraDNS' response time. This is  designed for situations when a MaraDNS server is receiving a large  number of queries, such as during a denial of service attack.

This is a numeric variable; its default value is zero, indicating that  all of MaraDNS' normal features are enabled. Higher numeric values  disable more features:  

The default level of dos_protection_level is 0 when there are one or  more zonefiles; 78 when there are no zone files.


If MaraDNS is compiled with as an authoritative server, then this  variable will tell MaraDNS which ipv6 address for the UDP server to;  for this variable to be set, MaraDNS must be bound to at least one ipv4  address.


If this is set to "YES", MaraDNS will not display the legal disclaimer  when starting up.


This is a list of IPs which we will send UDP packets longer than the  512 bytes RFC1035 permits if necessary. This is designed to allow  zoneserver, when used send regular DNS packets over TCP, to receive  packets with more data than can fit in a 512-byte DNS packet.

This variable only functions if MaraDNS is compiled as an authoritative  only server.


maradns_uid: The numeric UID that MaraDNS will run as

This accepts a single numerical value: The UID to run MaraDNS as.

MaraDNS, as soon as possible drops root privileges, minimizing the  damage a potential attacker can cause should there be a security  problem with MaraDNS. This is the UID maradns becomes.

The default UID is 707.


maradns_gid: The numeric GID that MaraDNS will run as.

This accepts a single numerical value: The GID to run MaraDNS as.

The default GID is 707.


max_ar_chain: The maximum number of records to display if a record in  the additional section (e.g., the IP of a NS server or the ip of a MX  exchange) has more than one value.

This is similar to max_chain, but applies to records in the  "additional" (or AR) section.

Due to limitations in the internal data structures that MaraDNS uses to  store RRs, if this has a value besides one, round robin rotates of  records are disabled.

The default value for this variable is 1.


max_chain: The maximum number of records to display in a chain of  records.

With DNS, it is possible to have more than one RR for a given domain  label. For example, "example.com" can have, as the A record, a list of  multiple ip addresses.

This sets the maximum number of records MaraDNS will show for a single  RR.

MaraDNS normally round-robin rotates records. Hence, all records for a  given DNS label (e.g. "example.com.") will be visible, although not at  the same time if there are more records than the value allowed with  max_chain

The default value for this variable is 8.


max_tcp_procs: The (optional) maximum number of processes the zone  server is allowed to run.

Sometimes, it is desirable to have a different number of maximum  allowed tcp processes than maximum allowed threads. If this variable is  not set, the maximum number of allowed tcp processes is "maxprocs".


max_total: The maximum number of records to show total for a given DNS  request.

This is the maximum total number of records that MaraDNS will make  available in a DNS reply.

The default value for this variable is 20.


max_mem is the maximum amount of memory we allow MaraDNS to allocate,  in bytes.

The default value of this is to allocate 2 megabytes for MaraDNS'  general use, and in addition, to allocate 3072 bytes for each element  we can have in the cache or DNS record that we are authoritatively  serving.


min_visible_ttl: The minimum value that we will will show as the TTL  (time to live) value for a resource record to other DNS servers and  stub resolvers. In other words, this is the minimum value we will ask  other DNS server to cache (keep in their memory) a DNS resource record.

The value is in seconds. The default value for this is 30; the minimum  value this can have is 5.

As an aside, RFC1123 section implies that zero-length TTL  records should be passed on with a TTL of zero. This, unfortunately,  breaks some stub resolvers (such as Mozilla's stub resolver).


remote_admin: Whether we allow verbose_level to be changed after  MaraDNS is started.

If remote_admin is set to 1, and admin_acl is set, any and all IPs  listed in admin_acl will be able to reset the value of verbose_level  from any value between 0 and 9 via a TXT query in the form of  5.verbose_level.maradns. What this will do is set verbose_query to the  value in the first digit of the query.

This is useful when wishing to temporarily increase the verbose_level  to find out why a given host name is not resolving, then decreasing  verbose_level so as to minimize the size of MaraDNS' log.


If this is set to 1, MaraDNS will not allow ANY queries, sending a  RFC8482 response if one is given to MaraDNS. If this is 0, ANY queries  are allowed. Default value: 1


When a CSV2 zone file doesn't have a SOA record in it, MaraDNS  generates a SOA record on the fly. This variable determines the host  name for the "SOA origin" (which is called the MNAME in RFC1035); this  is the host name of the DNS server which has the "master copy" of a  given DNS zone's file.

This host name is in human-readable format without a trailing dot,  e.g.:

synth_soa_origin = "ns1.example.com"

If this is not set, a synthetic SOA record will use the name of the  zone for the SOA origin (MNAME) field.


This determines whether we strictly follow RFC1912 section 2.2 with SOA  serial numbers. If this is set to 1 (the default value), we do not  strictly follow RFC1912 section 2.2 (the serial is a number, based on  the timestamp of the zone file, that is updated every six seconds), but  this makes it so that a serial number is guaranteed to be automatically  updated every time one edits a zone file.

If this is set to 2, the SOA serial number will be in YYYYMMDDHH  format, where YYYY is the 4-digit year, MM is the 2-digit month, DD is  the 2-digit day, and HH is the 2-digit hour of the time the zone file  was last updated (GMT; localtime doesn't work in a chroot()  environment). While this format is strictly RFC1912 compliant, the  disadvantage is that more than one edit to a zone file in an hour will  not update the serial number.

I strongly recommend, unless it is extremely important to have a DNS  zone that generates no warnings when tested at dnsreport.com, to have  this set to 1 (the default value). Having this set to 2 can result in  updated zone files not being seen by slave DNS servers.

Note that synth_soa_serial can only have a value of 1 on the native  Windows port.

On systems where time_t is 32-bit, MaraDNS will always act as if  synth_soa_serial has a value of 1. This is to avoid having MaraDNS use  invalid time and date values starting in late January of 2038; systems  with a 32-bit time_t can very well have their underlying system  libraries with regards to dates and times no longer correctly function  come 2038.


This only applies to the zoneserver (general DNS-over-TCP) program.

This is a list of IPs which are allowed to connect to the zoneserver  and send normal TCP DNS requests. The zoneserver will convert TCP DNS  requests in to UDP DNS requests, and send the UDP request in question  to the server specified in tcp_convert_server. Once it gets a reply from the UDP DNS server, it will convert the reply  in to a TCP request and send the reply back to the original TCP client.

Whether the RD (recursion desired) flag is set or not when converting a  TCP DNS request in to a UDP DNS request is determined by whether the  TCP client is on the recursive_acl list. Since MaraDNS 2.0 does not have recursion, the maradns daemon  ignores the RD bit (Deadwood will not process any queries without the  RD bit set).


This only applies to the zoneserver (general DNS-over-TCP) program.

This is the UDP server which we send a query to when converting DNS TCP  queries in to DNS UDP servers. Note that, while this value allows  multiple IPs, all values except the first one are presently ignored.


timestamp_type: The type of timestamp to display. The main purpose of  this option is to suppress the output of timestamps. Since duende uses  syslog() to output data, and since syslog() adds its own timestamp,  this option should be set to 5 when maradns is invoked with the duende  tool.

This option also allows people who do not use the duende tool to view  human-readable timestamps. This option only allows timestamps in GMT,  due to issues with showing local times in a chroot() environment.

This can have the following values:  


The string "Timestamp" followed by a UNIX timestamp


Just the bare UNIX timestamp


A GMT timestamp in the Spanish language


A (hopefully) local timestamp in the Spanish language


A timestamp using asctime(gmtime()); usually in the English language


No timestamp whatsoever is shown (this is the best option when maradns  is invoked with the duende tool).


ISO GMT timestamp is shown


ISO local timestamp is shown

On systems where time_t is 32-bit, MaraDNS will always act as if  timestamp_type has a value of 5, never showing a timestamp. This is to  avoid having MaraDNS show an invalid timestamp starting in late January  of 2038; systems with a 32-bit time_t can very well have their  underlying system libraries with regards to dates and times no longer  correctly function come 2038.

The default value for this variable is 5.


verbose_level: The number of messages we log to stdout

This can have five values:  


No messages except for the legal disclaimer and fatal parsing errors


Only startup messages logged (Default level)


Error queries logged


All queries logged


All actions adding and removing records from the cache logged

The default value for this variable is 1.


zone_transfer_acl: List of ips allowed to perform zone transfers with  the zone server

The format of this string is identical to the format of an ipv4_alias  entry.

Example Mararc File

# Example mararc file (unabridged version) 
# The various zones we support 
# We must initialize the csv2 hash, or MaraDNS will be unable to 
# load any csv2 zone files 
csv2 = {} 
# This is just to show the format of the file 
#csv2["example.com."] = "db.example.com" 
# The address this DNS server runs on.  If you want to bind  
# to multiple addresses, separate them with a comma like this: 
# ",," 
ipv4_bind_addresses = "" 
# The directory with all of the zone files 
chroot_dir = "/etc/maradns" 
# The numeric UID MaraDNS will run as 
maradns_uid = 99 
# The (optional) numeric GID MaraDNS will run as 
# maradns_gid = 99 
# Normally, MaraDNS has some MaraDNS-specific features, such as DDIP 
# synthesizing, a special DNS query ("erre-con-erre-cigarro.maradns.org."  
# with a TXT query returns the version of MaraDNS that a server is  
# running), unique handling of multiple QDCOUNTs, etc.  Some people  
# might not like these features, so I have added a switch that lets  
# a sys admin disable all these features.  Just give "no_fingerprint"  
# a value of one here, and MaraDNS should be more or less  
# indistinguishable from a tinydns server. 
no_fingerprint = 0 
# These constants limit the number of records we will display, in order 
# to help keep packets 512 bytes or smaller.  This, combined with round_robin 
# record rotation, help to use DNS as a crude load-balancer. 
# The maximum number of records to display in a chain of records (list 
# of records) for a given host name 
max_chain = 8 
# The maximum number of records to display in a list of records in the 
# additional section of a query.  If this is any value besides one, 
# round robin rotation is disabled (due to limitations in the current 
# data structure MaraDNS uses) 
max_ar_chain = 1 
# The maximum number of records to show total for a given question 
max_total = 20 
# The number of messages we log to stdout 
# 0: No messages except for fatal parsing errors and the legal disclaimer 
# 1: Only startup messages logged (default) 
# 2: Error queries logged 
# 3: All queries logged (but not very verbosely right now) 
verbose_level = 1 
# Here is a ACL which restricts who is allowed to perform zone transfer from  
# the zoneserver program 
# Simplest form: (IP:, 24 left bits in IP need to match) 
# and (IP:, netmask 
# are allowed to connect to the zone server  
# NOTE: The "maradns" program does not serve zones.  Zones are served 
# by the "zoneserver" program. 
#zone_transfer_acl = ","


If one should declare the same the same index twice with a dictionary  variable, MaraDNS will exit with a fatal error. This is because earlier  versions of MaraDNS acted in a different manner than Python 2.3.3. With  Python 2.3.3, the last declaration is used, while MaraDNS used to use  the first declaration.

Referenced By

maradns(8), zoneserver(8).

January 2002 MaraDNS reference