                                      NAME

   Deadwood - A fully recursive caching DNS resolver

                                  DESCRIPTION

   Deadwood is a fully recursive DNS cache. This is a DNS server with the
   following features:
     * Full support for both DNS recursion and DNS forwarding caching
     * Small size and memory footprint suitable for embedded systems
     * Simple and clean codebase
     * Secure design
     * Spoof protection: Strong cryptography used to determine the Query
       ID and source port
     * Ability to read and write the cache to a file
     * Dynamic cache that deletes entries not recently used
     * Ability to use expired entries in the cache when it is impossible
       to contact upstream DNS servers.
     * IPv6 support can be compiled in if desired
     * Both DNS-over-UDP and DNS-over-TCP are handled by the same daemon
     * Built-in dnswall functionality
     * The ability to assign names to IPv4 IPs as specified in one's
       dwood3rc file.
     * The ability to quickly load and use a large blocklist of names to
       not resolve.

                             COMMAND LINE ARGUMENTS

   Deadwood has a single optional command line argument: The location of
   the configuration file that Deadwood uses, specified with the "-f"
   flag. If this is not defined, Deadwood uses the file "/etc/dwood3rc" as
   the configuration file.

   In other words, invoking Deadwood as Deadwood will cause Deadwood to
   use /etc/dwood3rc as the configuration file; invoking Deadwood as
   Deadwood -f foobar will cause Deadwood to use the file "foobar" in the
   current working directory (the directory one is in when starting
   Deadwood) as the configuration file.

                           CONFIGURATION FILE FORMAT

   The Deadwood configuration file is modeled after Python 2's syntax.
   However, since Deadwood 2 is no longer supported by the Python Software
   Foundation, and since Deadwood configuration files can sometimes fail
   to parse in Python 3, Deadwood does not strictly follow Python 2
   syntax.

   In particular, leading whitespace is allowed in Deadwood configuration
   files.

                                PARAMETER TYPES

   Deadwood has three different parameter types:
     * Numeric parameters. Numeric parameters must not be surrounded by
       quotes, such as this example:
filter_rfc1918 = 0

       If a numeric parameter is surrounded by quotes, the error message
       "Unknown dwood3rc string parameter" will appear.
     * String parameters. String parameters must be surrounded by quotes,
       such as in this example:
bind_address = "127.0.0.1"

     * Dictionary parameters. All dictionary parameters must be
       initialized before use, and dictionary parameters must have both
       the dictionary index and the value for said index surrounded by
       quotes, such as in this example:
upstream_servers = {}
upstream_servers["."]="8.8.8.8, 8.8.4.4"

   All dwood3rc parameters except the following are numeric parameters:
     * bind_address (string)
     * cache_file (string)
     * chroot_dir (string)
     * ip_blacklist (string)
     * ip_blocklist (string)
     * ipv4_bind_addresses (string)
     * random_seed_file (string)
     * recursive_acl (string)
     * root_servers (dictionary)
     * upstream_servers (dictionary)
     * ip4 (dictionary)
     * ip6 (dictionary)
     * source_ip4 (string)

                              SUPPORTED PARAMETERS

   The Deadwood configuration file supports the following parameters:

bind_address

   This is the IP (or possibly IPv6) address we bind to.

cache_file

   This is the filename of the file used for reading and writing the cache
   to disk; this string can have lowercase letters, the '-' symbol, the
   '_' symbol, and the '/' symbol (for putting the cache in a
   subdirectory). All other symbols become a '_' symbol.

   This file is read and written as the user Deadwood runs as.

chroot_dir

   This is the directory the program will run from.

deliver_all

   This affects behavior in Deadwood 2.3, but has no effect in Deadwood 3.
   This variable is only here so Deadwood 2 rc files can run in Deadwood
   3.

dns_port

   This is the port Deadwood binds to and listens on for incoming
   connections. The default value for this is the standard DNS port: port
   53

filter_rfc1918

   When this has a value of 1, a number of different IP ranges are not
   allowed to be in DNS A replies:
     * 192.168.x.x
     * 172.[16-31].x.x
     * 10.x.x.x
     * 127.x.x.x
     * 169.254.x.x
     * 224.x.x.x
     * 0.0.x.x

   If one of the above IPs is detected in a DNS reply, and filter_rfc1918
   has a value of 1, Deadwood will return a synthetic "this host does not
   reply" response (a SOA record in the NS section) instead of the A
   record.

   The reason for this is to provide a "dnswall" that protects users for
   some kinds of attacks, as described at http://crypto.stanford.edu/dns/

   Please note that Deadwood only provides IPv4 "dnswall" functionality
   and does not help protect against IPv6 answers. If protection against
   certain IPv6 AAAA records is needed, either disable all AAAA answers by
   setting reject_aaaa to have a value of 1, or use an external program to
   filter undesired IPv4 answers (such as the dnswall program).

   The default value for this is 1

handle_noreply

   When this is set to 0, Deadwood sends no reply back to the client (when
   the client is a TCP client, Deadwood closes the TCP connection) when a
   UDP query is sent upstream and the upstream DNS never sends a reply.

   When this is set to 1, Deadwood sends a SERVER FAIL back to the client
   when a UDP query is sent upstream and the upstream DNS never sends a
   reply.

   The default value for this is 1

handle_overload

   When this has a value of 0, Deadwood sends no reply when a UDP query is
   sent and the server is overloaded (has too many pending connections);
   when it has a value of 1, Deadwood sends a SERVER FAIL packet back to
   the sender of the UDP query. The default value for this is 1.

hash_magic_number

   This used to be used for Deadwood's internal hash generator to keep the
   hash generator somewhat random and immune to certain types of attacks.
   In Deadwood 3.0, entropy for the hash function is created by looking at
   the contents of /dev/urandom (secret.txt on Windows machines) and the
   current timestamp. This parameter is only here so older configuration
   files do not break in Deadwood 3.0.

ip4

   This is a dictionary variable which allows us to have given names
   resolve to bogus IPv4 addresses. Here, we have the name "maradns.foo"
   resolve to "10.10.10.10" and "kabah.foo" resolve to "10.11.11.11",
   regardless of what real values these DNS records may have:
ip4 = {}
ip4["maradns.foo."] = "10.10.10.10"
ip4["kabah.foo."] = "10.11.11.11"

   Note that a given name can only resolve to a single IP, and that the
   records have a fixed TTL of 30 seconds.

   It is also possible to use ip4 to set up a blocklist by using "X" for
   the IP. When this is done, an IPv4 request for a given hostname results
   in a synthetic "this name does not exist" response. In addition, the
   corresponding IPv6 request will also return that "name does not exist"
   reply. For example:
ip4 = {}
ip4["evil.example.com."] = "X"

   Here, both the IPv4 and the IPv6 query for "evil.example.com" will not
   resolve in Deadwood.

ip6

   Like ip4, ip6 uses a similar syntax to have bogus IPv6 addresses. We
   don't use standard notation for IPv6 addresses. Instead, we we use
   32-character hex addresses (case insensitive); to make it easier to
   count long strings of "0"s, the "_" acts like a 0; we also ignore "-"
   (dash) and " " (space) in ip6 strings. Here is an example:
ip6 = {}
ip6["maradns.foo."] = "20010db84d617261444e530000001234"
ip6["kabah.foo."] = "2001-0DB8-4D61-7261 444E-5300-__00-2345"

ip_blocklist

   This is a list of IPs that we do not allow to be in the answer to a DNS
   request. The reason for this is to counteract the practice some ISPs
   have of converting a "this site does not exist" DNS answer in to a page
   controlled by the ISP; this results in possible security issues.

   This parameter only accepts individual IPs, and does not use netmasks.

   Note that this parameter used to be called ip_blacklist; while the
   ip_blacklist name still works as before, ip_blocklist is the current
   name.

maradns_uid

   The user-id Deadwood runs as. This can be any number between 10 and
   16777216; the default value is 707 (a system UID which should be
   unused). This value is not used on Windows systems.

maradns_gid

   The group-id Deadwood runs as. This can be any number between 10 and
   16777216; the default value is 707. This value is not used on Windows
   systems.

max_ar_chain

   Whether resource record rotation is enabled. If this has a value of 1,
   resource record rotation is enabled, otherwise resource record rotation
   is disabled.

   Resource record rotation is usually desirable, since it allows DNS to
   act like a crude load balancer. However, on heavily loaded systems it
   may be desirable to disable it to reduce CPU usage.

   The reason for the unusual name for this variable is to retain
   compatibility with MaraDNS mararc files.

   The default value is 1: Resource record rotation enabled.

max_inflights

   The maximum number of simultaneous clients we process at the same time
   for the same query.

   If, while processing a query for, say, "example.com.", another DNS
   client sends to Deadwood another query for example.com, instead of
   creating a new query to process example.com, Deadwood will attach the
   new client to the same query that is already "in flight", and send a
   reply to both clients once we have an answer for example.com.

   This is the number of simultaneous clients a given query can have. If
   this limit is exceeded, subsequents clients with the same query are
   refused until an answer is found. If this has a value of 1, we do not
   merge multiple requests for the same query, but give each request its
   own connection.

   The default value is 8.

max_ttl

   The maximum amount of time we will keep an entry in the cache, in
   seconds (also called "Maximum TTL").

   This is the longest we will keep an entry cached. The default value for
   this parameter is 86400 (one day); the minimum value is 300 (5 minutes)
   and the maximum value this can have is 7776000 (90 days).

   The reason why this parameter is here is to protect Deadwood from
   attacks which exploit there being stale data in the cache, such as the
   "Ghost Domain Names" attack.

maximum_cache_elements

   The maximum number of elements our cache is allowed to have. This is a
   number between 32 and 16,777,216; the default value for this is 1024.
   Note that, if writing the cache to disk or reading the cache from disk,
   higher values of this will slow down cache reading/writing.

   The amount of memory each cache entry uses is variable depending on the
   operating system used and the size of memory allocation pages assigned.
   In Windows XP, for example, each entry uses approximately four
   kilobytes of memory and Deadwood has an overhead of approximately 512
   kilobytes. So, if there are 512 cache elements, Deadwood uses
   approximately 2.5 megabytes of memory, and if there are 1024 cache
   elements, Deadwood uses approximately 4.5 megabytes of memory. Again,
   these numbers are for Windows XP and other operating systems will have
   different memory allocation numbers.

   Please note that, as of Deadwood 3.5.0004, is is no longer needed to
   increase maximum_cache_elements to store upstream_server and
   root_server entries.

maxprocs

   This is the maximum number of pending remote UDP connections Deadwood
   can have. The default value for this is 1024.

max_tcp_procs

   This is the number of allowed open TCP connections. Default value: 8

min_ttl

   The minimum amount of time we will keep an entry in the cache, in
   seconds (also called "Minimum TTL").

num_retries

   The number of times we retry to send a query upstream before giving up.
   If this is 0, we only try once; if this is 1, we try twice, and so on,
   up to 32 retries. Note that each retry takes timeout_seconds seconds
   before we retry again. Default value: 5

ns_glueless_type

   The RR type we send to resolve glueless records. This should always be
   1 (A; i.e. IPv4 DNS servers). This should never be ANY, see RFC8482.
   This should not be any other value, since only A glueless NS referrals
   have ever been tested with Deadwood.

   The reason why this exists is because, often times in DNS, we get a
   reply like "The name server for this foo.example.com and no I do not
   have the IP for foo.example.com" when recursively solving an answer.
   So, the question is this: Is foo.example.com an IPv4 DNS server, an
   IPv6 server, or both?

   On today's internet (mid-2020, during the COVID-19 crisis), the answer
   is that the name server in question is only on the IPv4 Internet. IPv6
   is now mainstream (e.g. my ISP gives me a /64 and I no longer have to
   tunnel through he.net to try out IPv6), but most servers are still IPv4
   only (e.g. my domains are only on IPv4, and amazon.com does not have an
   IPv6 address).

   The reason this parameter exists is because, when I was writing the
   recursive code for Deadwood, I was thinking of a future where IPv6 is
   prevalent enough that we would have DNS servers with only IPv6
   addresses, and glueless NS referrals (the "foo.example.com" case above)
   would point to servers with IPv6, but not IPv4, addresses.

   That day may yet come, but preparing Deadwood to still be a viable DNS
   server when that day comes will require more than changing the RR type
   sent when it gets a glueless NS referral.

random_seed_file

   This is a file that contains random numbers, and is used as a seed for
   the cryptographically strong random number generator. Deadwood will try
   to read 256 bytes from this file (the RNG Deadwood uses can accept a
   stream of any arbitrary length).

   Note that the hash compression function obtains some of its entropy
   before parsing the mararc file, and is hard-coded to get entropy from
   /dev/urandom (secret.txt on Windows systems). Most other entropy used
   by Deadwood comes from the file pointed to by random_seed_file.

recurse_min_bind_port

   The lowest numbered port Deadwood is allowed to bind to; this is a
   random port number used for the source port of outgoing queries, and is
   not 53 (see dns_port above). This is a number between 1025 and 32767,
   and has a default value of 15000. This is used to make DNS spoofing
   attacks more difficult.

recurse_number_ports

   The number of ports Deadwood binds to for the source port for outgoing
   connections; this is a power of 2 between 256 and 32768. This is used
   to make DNS spoofing attacks more difficult. The default value is 4096.

recursive_acl

   This is a list of who is allowed to use Deadwood to perform DNS
   recursion, in "ip/mask" format. Mask must be a number between 0 and 32
   (for IPv6, between 0 and 128). For example, "127.0.0.1/8" allows local
   connections.

reject_aaaa

   If this has a value of 1, a bogus SOA "not there" reply is sent
   whenever an AAAA query is sent to Deadwood. In other words, every time
   a program asks Deadwood for an IPv6 IP address, instead of trying to
   process the request, when this is set to 1, Deadwood pretends the host
   name in question does not have an IPv6 address.

   This is useful for people who aren't using IPv6 but use applications
   (usually *NIX command like applications like "telnet") which slow
   things down trying to find an IPv6 address.

   This has a default value of 0. In other words, AAAA queries are
   processed normally unless this is set.

reject_mx

   When this has the default value of 1, MX queries are silently dropped
   with their IP logged. A MX query is a query that is only done by a
   machine if it wishes to be its own mail server sending mail to machines
   on the internet. This is a query an average desktop machine (including
   one that uses Outlook or another mail user agent to read and send
   email) will never make.

   Most likely, if a machine is trying to make a MX query, the machine is
   being controlled by a remote source to send out undesired "spam" email.
   This in mind, Deadwood will not allow MX queries to be made unless
   reject_mx is explicitly set with a value of 0.

   Before disabling this, please keep in mind that Deadwood is optimized
   to be used for web surfing, not as a DNS server for a mail hub. In
   particular, the IPs for MX records are removed from Deadwood's replies
   and Deadwood needs to perform additional DNS queries to get the IPs
   corresponding to MX records, and Deadwood's testing is more geared for
   web surfing (almost 100% A record lookup) and not for mail delivery
   (extensive MX record lookup).

reject_ptr

   If this has a value of 1, a bogus SOA "not there" reply is sent
   whenever a PTR query is sent to Deadwood. In other words, every time a
   program asks Deadwood for "reverse DNS lookup" -- the hostname for a
   given IP address -- instead of trying to process the request, when this
   is set to 1, Deadwood pretends the IP address in question does not have
   a hostname.

   This is useful for people who are getting slow DNS timeouts when trying
   to perform a reverse DNS lookups on IPs.

   This has a default value of 0. In other words, PTR queries are
   processed normally unless this is set.

resurrections

   If this is set to 1, Deadwood will try to send an expired record to the
   user before giving up. If it is 0, we don't. Default value: 1

root_servers

   This is a list of root servers; its syntax is identical to
   upstream_servers (see below). This is the type of DNS service ICANN,
   for example, runs. These are servers used that do not give us complete
   answers to DNS questions, but merely tell us which DNS servers to
   connect to to get an answer closer to our desired answer.

   Please note that, as of Deadwood 3.5.0004, it is no longer needed to
   increase maximum_cache_elements to store root_server entries.

source_ip4

   With certain complicated networks, it may be desirable to set the
   source IP of queries sent to upstream or root DNS servers. If so, set
   this parameter to have the dotted decimal IPv4 address to use when
   sending IPv4 queries to an upstream DNS server.

   Use this parameter with caution; Deadwood can very well become
   non-functional if one uses a source IPv4 address which Deadwood is not
   bound to.

tcp_listen

   In order to enable DNS-over-TCP, this variable must be set and have a
   value of 1. Default value: 0

timeout_seconds

   This is how long Deadwood will wait before giving up and discarding a
   pending UDP DNS reply. The default value for this is 1, as in 1 second,
   unless Deadwood was compiled with FALLBACK_TIME enabled.

timeout_seconds_tcp

   How long to wait on an idle TCP connection before dropping it. The
   default value for this is 4, as in 4 seconds.

ttl_age

   Whether TTL aging is enabled; whether entries in the cache have their
   TTLs set to be the amount of time the entries have left in the cache.

   If this has a value of 1, TTL entries are aged. Otherwise, they are
   not. The default value for this is 1.

upstream_port

   This is the port Deadwood uses to connect or send packets to the
   upstream servers. The default value for this is 53; the standard DNS
   port.

upstream_servers

   This is a list of DNS servers that the load balancer will try to
   contact. This is a dictionary variable (array indexed by a string
   instead of by a number) instead of a simple variable. Since
   upstream_servers is a dictionary variable, it needs to be initialized
   before being used.

   Deadwood will look at the name of the host that it is trying to find
   the upstream server for, and will match against the longest suffix it
   can find.

   For example, if someone sends a query for "www.foo.example.com" to
   Deadwood, Deadwood will first see if there is an upstream_servers
   variable for "www.foo.example.com.", then look for "foo.example.com.",
   then look for "example.com.", then "com.", and finally ".".

   Here is an example of upstream_servers:
upstream_servers = {} # Initialize dictionary variable
upstream_servers["foo.example.com."] = "192.168.42.1"
upstream_servers["example.com."] = "192.168.99.254"
upstream_servers["."] = "10.1.2.3, 10.1.2.4"

   In this example, anything ending in "foo.example.com" is resolved by
   the DNS server at 192.168.42.1; anything else ending in "example.com"
   is resolved by 192.168.99.254; and anything not ending in "example.com"
   is resolved by either 10.1.2.3 or 10.1.2.4.

   Important: the domain name upstream_servers points to must end in a "."
   character. This is OK:
upstream_servers["example.com."] = "192.168.42.1"

   But this is not OK:
upstream_servers["example.com"] = "192.168.42.1"

   The reason for this is because BIND engages in unexpected behavior when
   a host name doesn't end in a dot, and by forcing a dot at the end of a
   hostname, Deadwood doesn't have to guess whether the user wants BIND's
   behavior or the "normal" behavior.

   If neither root_servers nor upstream_servers are set, Deadwood sets
   upstream_servers to use the https://quad9.net servers, as follows:

9.9.9.9
149.112.112.112

   Please note that, as of Deadwood 3.5.0004, is is no longer needed to
   increase maximum_cache_elements to store upstream_server entries.

verbose_level

   This determines how many messages are logged on standard output; larger
   values log more messages. The default value for this is 3.

                             ip/mask format of IPs

   Deadwood uses a standard ip/netmask formats to specify IPs. An ip is in
   dotted-decimal format, e.g. "10.1.2.3" (or in IPv6 format when IPv6
   support is compiled in).

   The netmask is used to specify a range of IPs. The netmask is a single
   number between 1 and 32 (128 when IPv6 support is compiled in), which
   indicates the number of leading "1" bits in the netmask.

   10.1.1.1/24 indicates that any ip from 10.1.1.0 to 10.1.1.255 will
   match.

   10.2.3.4/16 indicates that any ip from 10.2.0.0 to 10.2.255.255 will
   match.

   127.0.0.0/8 indicates that any ip with "127" as the first octet
   (number) will match.

   The netmask is optional, and, if not present, indicates that only a
   single IP will match.

                                  DNS over TCP

   DNS-over-TCP needs to be explicitly enabled by setting tcp_listen to 1.

   Deadwood extracts useful information from UDP DNS packets marked
   truncated which almost always removes the need to have DNS-over-TCP.
   However, Deadwood does not cache DNS packets larger than 512 bytes in
   size that need to be sent using TCP. In addition, DNS-over-TCP packets
   which are "incomplete" DNS replies (replies which a stub resolver can
   not use, which can be either a NS referral or an incomplete CNAME
   reply) are not handled correctly by Deadwood.

   Deadwood has support for both DNS-over-UDP and DNS-over-TCP; the same
   daemon listens on both the UDP and TCP DNS port.

   Only UDP DNS queries are cached. Deadwood does not support caching over
   TCP; it handles TCP to resolve the rare truncated reply without any
   useful information or to work with very uncommon non-RFC-compliant
   TCP-only DNS resolvers. In the real world, DNS-over-TCP is almost never
   used.

                              Parsing other files

   It is possible to have Deadwood, while parsing the dwood3rc file, read
   other files and parse them as if they were dwood3rc files.

   This is done using execfile. To use execfile, place a line like this in
   the dwood3rc file:

   execfile("path/to/filename")

   Where path/to/filename is the path to the file to be parsed like a
   dwood3rc file.

   All files must be in or under the directory /etc/deadwood/execfile.
   Filenames can only have lower-case letters and the underscore character
   ("_"). Absolute paths are not allowed as the argument to execfile; the
   filename can not start with a slash ("/") character.

   If there is a parse error in the file pointed to by execfile, Deadwood
   will report the error as being on the line with the execfile command in
   the main dwood3rc file. To find where a parse error is in the sub-file,
   use something like "Deadwood -f /etc/deadwood/execfile/filename" to
   find the parse error in the offending file, where "filename" is the
   file to to parsed via execfile.

                                  IPV6 support

   This server can also be optionally compiled to have IPv6 support. In
   order to enable IPv6 support, add '-DIPV6' to the compile-time flags.
   For example, to compile this to make a small binary, and to have IPv6
   support:
        export FLAGS='-Os -DIPV6'
        make

                                    SECURITY

   Deadwood is a program written with security in mind.

   In addition to use a buffer-overflow resistant string library and a
   coding style and SQA process that checks for buffer overflows and
   memory leaks, Deadwood uses a strong pseudo-random number generator
   (The 32-bit version of RadioGatun) to generate both the query ID and
   source port. For the random number generator to be secure, Deadwood
   needs a good source of entropy; by default Deadwood will use
   /dev/urandom to get this entropy. If you are on a system without
   /dev/urandom support, it is important to make sure that Deadwood has a
   good source of entropy so that the query ID and source port are hard to
   guess (otherwise it is possible to forge DNS packets).

   The Windows port of Deadwood includes a program called
   "mkSecretTxt.exe" that creates a 64-byte (512 bit) random file called
   "secret.txt" that can be used by Deadwood (via the "random_seed_file"
   parameter); Deadwood also gets entropy from the timestamp when Deadwood
   is started and Deadwood's process ID number, so it is same to use the
   same static secret.txt file as the random_seed_file for multiple
   invocations of Deadwood.

   Note that Deadwood is not protected from someone on the same network
   viewing packets sent by Deadwood and sending forged packets as a reply.

   To protect Deadwood from certain possible denial-of-service attacks, it
   is best if Deadwood's prime number used for hashing elements in the
   cache is a random 31-bit prime number. The program RandomPrime.c
   generates a random prime that is placed in the file DwRandPrime.h that
   is regenerated whenever either the program is compiled or things are
   cleaned up with make clean. This program uses /dev/urandom for its
   entropy; the file DwRandPrime.h will not be regenerated on systems
   without /dev/urandom.

   On systems without direct /dev/urandom support, it is suggested to see
   if there is a possible way to give the system a working /dev/urandom.
   This way, when Deadwood is compiled, the hash magic number will be
   suitably random.

   If using a precompiled binary of Deadwood, please ensure that the
   system has /dev/urandom support (on Windows system, please ensure that
   the file with the name secret.txt is generated by the included
   mkSecretTxt.exe program); Deadwood, at runtime, uses /dev/urandom
   (secret.txt in Windows) as a hardcoded path to get entropy (along with
   the timestamp) for the hash algorithm.

                                    COMMENTS

   Deadwood's configuration file format supports two kinds of comments:
# This is a comment

   Here, a comment starts with the # character and continues until the end
   of the line. In some circumstances, a comment can start after a
   variable is set, for example:
bind_address="127.0.0.1" # IP we bind to

   The second comment type supports multi-line comments. For example:
_rem={}
_rem={ #_rem --[=[
"""
 We are now in a multi-line comment.
 This allows a long explanation to be
 in a Deadwood configuration file
""" # ]=]
}

   The actual format is _rem={ at the start of a line, which begins a
   multi-line comment. The comment continues until a } is seen. The reason
   for this unusual format is that it allows a Deadwood configuration file
   to have multi-line comments in a form which are compatible with both
   Lua and Python, as can be seen in the above example.

                                 DAEMONIZATION

   Deadwood does not have any built-in daemonization facilities; this is
   handled by the external program Duende or any other daemonizer.

                           Example configuration file

   Here is an example dwood3rc configuration file:
# This is an example deadwood rc file
# Note that comments are started by the hash symbol

bind_address="127.0.0.1" # IP we bind to

# The following line is disabled by being commented out
#bind_address="::1" # We have optional IPv6 support

# Directory we run program from (not used in Win32)
chroot_dir = "/etc/deadwood"

# The following upstream DNS servers are Google's
# (as of December 2009) public DNS servers.  For
# more information, see the page at
# http://code.google.com/speed/public-dns/
#
# If neither root_servers nor upstream_servers are set,
# Deadwood will use the default ICANN root servers.
#upstream_servers = {}
#upstream_servers["."]="8.8.8.8, 8.8.4.4"

# Who is allowed to use the cache.  This line
# allows anyone with "127.0" as the first two
# digits of their IP to use Deadwood
recursive_acl = "127.0.0.1/16"

# Maximum number of pending requests
maxprocs = 2048

# Send SERVER FAIL when overloaded
handle_overload = 1

maradns_uid = 99 # UID Deadwood runs as
maradns_gid = 99 # GID Deadwood runs as

maximum_cache_elements = 60000

# If you want to read and write the cache from disk,
# make sure chroot_dir above is readable and writable
# by the maradns_uid/gid above, and uncomment the
# following line.
#cache_file = "dw_cache"

# If your upstream DNS server converts "not there" DNS replies
# in to IPs, this parameter allows Deadwood to convert any reply
# with a given IP back in to a "not there" IP.  If any of the IPs
# listed below are in a DNS answer, Deadwood converts the answer
# in to a "not there"
#ip_blocklist = "10.222.33.44, 10.222.3.55"

# By default, for security reasons, Deadwood does not allow IPs in
# the 192.168.x.x, 172.[16-31].x.x, 10.x.x.x, 127.x.x.x,
# 169.254.x.x, 224.x.x.x, or 0.0.x.x range.  If using Deadwood
# to resolve names on an internal network, uncomment the
# following line:
#filter_rfc1918 = 0

                                      BUGS

   Deadwood does not follow RFC2181's advice to ignore DNS responses with
   the TC (truncated) bit set, but instead extracts the first RR. If this
   is not desired, set the undocumented parameter truncation_hack to 0
   (but read the DNS over TCP section of this man page).

   Deadwood can not process DNS resource record types with numbers between
   65392 and 65407. These RR types are marked by the IANA for "private
   use"; Deadwood reserves these record types for internal use. This is
   only 16 record types out of the 65536 possible DNS record types (only
   71 have actually been assigned by IANA, so this is a non-issue in the
   real world).

   It is not clear whether the DNS RFCs allow ASCII control characters in
   DNS names. Even if they were, Deadwood does not allow ASCII control
   characters (bytes with a value less then 32) in DNS names. Other
   characters (UTF-8, etc.) are allowed.

   Combining a CNAME record with other records is prohibited in RFC1034
   section 3.6.2 and RFC1912 section 2.4; it makes an answer ambiguous.
   Deadwood handles this ambiguity differently than some other DNS
   servers.

                                LEGAL DISCLAIMER

   THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY EXPRESS OR
   IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
   ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
   IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   POSSIBILITY OF SUCH DAMAGE.

                                    AUTHORS

   Sam Trenholme (http://www.samiam.org) is responsible for this program
   and man page. He appreciates all of Jean-Jacques Sarton's help giving
   this program IPv6 support.

