Unlike Python, however, a mararc file can only use certain variable names, and the variables can only be declared as described below.
# This is a commentThe MaraDNS parser also ignores lines which contain only white space.
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.
Examples:
ipv4_bind_addresses = "10.2.19.83" ipv4_bind_addresses += ",10.2.66.74" ipv4_bind_addresses += ",10.3.87.13"ipv4_bind_addresses now has the value "10.2.19.83,10.2.66.74,10.3.87.13"
ipv4_alias["icann"] = "198.41.0.4" ipv4_alias["icann"] += ",192.228.79.201" ipv4_alias["icann"] += ",192.33.4.12,128.8.10.90"
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.
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["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["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. "10.1.2.3".
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.
10.1.1.1/255.255.255.0 is identical to 10.1.1.1/24
10.2.3.4/16 indicates that any ip from 10.2.0.0 to 10.2.255.255 will match.
10.2.3.4/255.255.0.0 is identical to 10.2.3.4/16
127.0.0.0/8 indicates that any ip with "127" as the first octet (number) will match.
127.0.0.0/255.0.0.0 is identical to 127.0.0.0/8
The netmask is optional, and, if not present, indicates that only a single IP will "match". e.g:
10.9.9.9/32, 10.9.9.9/255.255.255.255, and 10.9.9.9 are all functionally identical, and indicate that only the ip 10.9.9.9 will match.
The significance of "match" depends on what we use the ipv4 alias for.
ipv4 aliases can nest. E.g:
ipv4_alias["susan"] = "10.6.7.8/24" ipv4_alias["office"] = "susan,10.9.9.9"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.
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.
This accepts one or more ipv4 IPs in dotted-decimal (e.g. "127.0.0.1") notation, and specifies what IP addresses the MaraDNS server will listen on. Multiple bind addresses are separated with a comma, like this: "10.1.2.3, 10.1.2.4, 127.0.0.1"
This accepts a single IP in dotted-decimal (e.g. "127.0.0.1") 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 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:
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.
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.
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 is a numeric variable; its default value is zero, indicating that all of MaraDNS' normal features are enabled. Higher numeric values disable more features:
This variable only functions if MaraDNS is compiled as an authoritative only server.
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.
This accepts a single numerical value: The GID to run MaraDNS as.
The default GID is 707.
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.
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.
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".
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.
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.
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 6.1.2.1 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).
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.
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.
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 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 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.
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:
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.
This can have five values:
The default value for this variable is 1.
The format of this string is identical to the format of an ipv4_alias entry.
# 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:
# "10.1.2.3,10.1.2.4,127.0.0.1"
ipv4_bind_addresses = "127.0.0.1"
# 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: 10.1.1.1/24 (IP: 10.1.1.1, 24 left bits in IP need to match)
# and 10.100.100.100/255.255.255.224 (IP: 10.100.100.100, netmask
# 255.255.255.224) 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 = "10.1.1.1/24, 10.100.100.100/255.255.255.224"