Provided by: opendkim_2.11.0~alpha-12_amd64 bug


       opendkim.conf - Configuration file for opendkim




       opendkim(8) implements the DKIM specification for signing and verifying e-mail messages on
       a per-domain basis.  This file is its configuration file.

       Blank lines are ignored.  Lines containing a hash ("#") character  are  truncated  at  the
       hash character to allow for comments in the file.

       Other  content should be the name of a parameter, followed by white space, followed by the
       value of that parameter, each on a separate line.

       For parameters that are Boolean in nature, only the first byte of the value is  processed.
       For  positive  values,  the following are accepted: "T", "t", "Y", "y", "1".  For negative
       values, the following are accepted: "F", "f", "N", "n", "0".

       Many, but not all, of these parameters are also  available  as  command  line  options  to
       opendkim(8).   However,  new parameters are generally not added as command line options so
       the complete set of options is available here, and thus use of the configuration  file  is
       encouraged.   In  some future release, the set of available command line options is likely
       to get trimmed.

       See the opendkim(8) man page for  details  about  how  and  when  the  configuration  file
       contents are reloaded.

       Some  of  these  parameters are listed as having a type of "dataset".  See the opendkim(8)
       man page for a description of such parameters.

       Unless otherwise stated, Boolean values default to "false", integer values default  to  0,
       and string and dataset values default to being undefined.


       AllowSHA1Only (Boolean)
              Permit  verify  mode  when  only  SHA1 support is available.  RFC6376 requires that
              verifiers implement both SHA1 and SHA256 support.  Setting this feature changes the
              absence of SHA256 support from an error to a warning.

       AlwaysAddARHeader (Boolean)
              Add  an  "Authentication-Results:"  header  field  even  to  unsigned messages from
              domains with no "signs all" policy.  The reported DKIM result  will  be  "none"  in
              such  cases.   Normally  unsigned  mail  from non-strict domains does not cause the
              results header field to be added.

       AuthservID (string)
              Sets the "authserv-id" to use when generating  the  Authentication-Results:  header
              field  after  verifying  a  message.   The  default  is  to use the name of the MTA
              processing the message.  If the string "HOSTNAME" is provided, the name of the host
              running the filter (as returned by the gethostname(3) function) will be used.

       AuthservIDWithJobID (Boolean)
              If  "true",  requests  that  the  authserv-id  portion of the added Authentication-
              Results: header fields contain the job ID of the message being evaluated.

       AutoRestart (Boolean)
              Automatically re-start  on  failures.   Use  with  caution;  if  the  filter  fails
              instantly after it starts, this can cause a tight fork(2) loop.

       AutoRestartCount (integer)
              Sets the maximum automatic restart count.  After this number of automatic restarts,
              the filter will give up and terminate.  A value of 0 implies no limit; this is  the

       AutoRestartRate (string)
              Sets  the  maximum  automatic restart rate.  If the filter begins restarting faster
              than the rate defined here, it will give up and terminate.  This is a string of the
              form  n/t[u]  where  n  is  an  integer limiting the count of restarts in the given
              interval and t[u] defines the time interval through which the rate is calculated; t
              is an integer and u defines the units thus represented ("s" or "S" for seconds, the
              default; "m" or "M" for minutes; "h" or "H" for hours; "d" or "D" for  days).   For
              example,  a  value  of  "10/1h" limits the restarts to 10 in one hour.  There is no
              default, meaning restart rate is not limited.

       Background (Boolean)
              Causes opendkim to fork and exits immediately, leaving the service running  in  the
              background.  The default is "true".

       BaseDirectory (string)
              If  set,  instructs  the filter to change to the specified directory using chdir(2)
              before doing anything else.  This means  any  files  referenced  elsewhere  in  the
              configuration  file  can be specified relative to this directory.  It's also useful
              for arranging that any crash dumps will be saved to a specific location.

       BodyLengthDB (dataset)
              Requests that opendkim include a "l=" body length tag when the set contains any  of
              the  envelope  recipient addresses.  The addresses presented are tested against the
              database in various forms as described  under  the  SigningTable  setting  (below).
              This feature of the protocol exists to improve the likelihood that a signature will
              survive transit through a mailing list server, as they commonly append  footers  to
              messages.   Note,  however,  that  this  creates  a  potential security issue since
              someone could add arbitrary text to the signed  message  and  the  signature  would
              still validate.  See the DKIM specification for details.

       BogusKey (string)
              Instructs  the filter to treat a passing signature associated with a bogus (forged)
              key in a special way.  Possible values are neutral  (return  a  "neutral"  result),
              none  (take  no  special  action)  and  fail  (return  a "fail" result; this is the

       CaptureUnknownErrors (Boolean)
              When set, and on systems where MTA quarantine is available, the filter will request
              quarantine of a message that results in an internal error or resource exhaustion.

       Canonicalization (string)
              Selects  the  canonicalization  method(s)  to  be used when signing messages.  When
              verifying,   the   message's   DKIM-Signature:   header   field    specifies    the
              canonicalization  method.   The recognized values are relaxed and simple as defined
              by the DKIM specification.  The default is  simple.   The  value  may  include  two
              different canonicalizations separated by a slash ("/") character, in which case the
              first will be applied to the header and the second to the body.

       ChangeRootDirectory (string)
              Requests that the operating system change  the  effective  root  directory  of  the
              process to the one specified here prior to beginning execution.  chroot(2) requires
              superuser access. A warning will be generated if UserID is not also set.

       ClockDrift (integer)
              Sets the tolerance in seconds to be applied when determining  whether  a  signature
              was either expired or generated in the future.  The default is 300.

       Diagnostics (Boolean)
              Requests the inclusion of "z=" tags in signatures, which encode the original header
              field set  for  use  by  verifiers  when  diagnosing  verification  failures.   Not
              recommended for normal operation.

       DiagnosticDirectory (string)
              Directory into which to write diagnostic reports when message verification fails on
              a message bearing a "z=" tag.  If not  set  (the  default),  these  files  are  not

       DisableCryptoInit (Boolean)
              If  set,  skips  initialization  of the SSL library initialization steps, which are
              normaly required in multi-threaded environments.  This assumes some  other  library
              opendkim is using will do the required initialization and shutdown.

       DNSConnect (Boolean)
              Requests  that  the  asynchronous  resolver start using TCP immediately rather than
              using UDP until TCP is actually needed.  Does not work with all resolvers.

       DNSTimeout (integer)
              Sets the DNS timeout in seconds.  A value  of  0  causes  an  infinite  wait.   The
              default is 5.  Ignored if not using an asynchronous resolver package.  See also the
              NOTES section below.

       Domain (dataset)
              A set of domains whose mail should be signed  by  this  filter.   Mail  from  other
              domains will be verified rather than being signed.

              This  parameter is not required if a SigningTable is in use; in that case, the list
              of signed domains is implied by the lines in that file.

              This parameter is ignored if a KeyTable is defined.

       DomainKeysCompat (boolean)
              If set, backward compatibility with DomainKeys (RFC4870) key  records  is  enabled.
              When not set, such keys are considered to be syntactically invalid.  The default is

       DontSignMailTo (dataset)
              A set of e-mail address, mail to which should never be signed by the filter.   Note
              that  this is an "any" feature; if any one of the recipients of the message matches
              a member of this list, the message will not be signed.

       EnableCoredumps (boolean)
              On systems that have such support, make an explicit request to the kernel  to  dump
              cores  when  the filter crashes for some reason.  Some modern UNIX systems suppress
              core dumps during crashes for security reasons if the user ID  has  changed  during
              the lifetime of the process.  Currently only supported on Linux.

       ExemptDomains (dataset)
              Specifies  a  set  of  domains,  mail  from which should be ignored entirely by the
              filter.  This is similar to the PeerList setting except that it bases its  decision
              on  the sender of the message as identified from the header fields or other message
              data, not the identity of the SMTP client sending the message.

       ExternalIgnoreList (dataset)
              Identifies a set of "external" hosts that may send mail through the server  as  one
              of  the  signing  domains  without  credentials  as  such.   This has the effect of
              suppressing the "external host (hostname) tried  to  send  mail  as  (domain)"  log
              messages.   Entries  in  the  data  set  should be of the same form as those of the
              PeerList option below.  The set is empty by default.

       FinalPolicyScript (string)
              Gives the name of a Lua script that should be run after the entire message has been
              received.   This  can  be  used  to  enact  local  policy decisions such as message
              rejection, quarantine, rerouting, etc. based on signatures found  on  the  message,
              the  results  of  attempts  to  verify them, and other properties of the message or
              signatures.  See opendkim-lua(3) for details.

       FixCRLF (Boolean)
              Requests that the DKIM library convert bare  CRs  and  LFs  to  CRLFs  during  body
              canonicalization,  anticipating  that an MTA somewhere before delivery will do that
              conversion anyway.  The default is to leave them as-is.

       IdentityHeader (string)
              This specifies the header field where an identity is stored.  (Experimental feature
              not enabled for this installation.)

       IdentityHeaderRemove (Boolean)
              Remove  the  IdentityHeader  after  signing.  (Experimental feature not enabled for
              this installation.)

       IgnoreMalformedMail (boolean)
              Silently passes malformed messages without alteration.  This includes messages that
              fail  the RequiredHeaders check, if enabled.  The default is to pass those messages
              but add an Authentication-Results field indicating that they were malformed.

       Include (string)
              Names a file to be opened and read as an additional configuration file.  Nesting is
              allowed to a maximum of five levels.

       InternalHosts (dataset)
              Identifies  a  set internal hosts whose mail should be signed rather than verified.
              Entries in this data set follow the same form  as  those  of  the  PeerList  option
              below.   If  not  specified,  the  default  of  "" is applied.  Naturally,
              providing a value here overrides the default, so if mail from  should  be
              signed, the list provided here should include that address explicitly.

       KeepAuthResults (boolean)
              Suppresses  removal of Authentication-Results header fields containing DKIM results
              apparently added by this filter (usually the result  of  a  misconfiguration  or  a

       KeepTemporaryFiles (boolean)
              Instructs  the  filter  to  create  temporary  files containing the header and body
              canonicalizations of messages that are signed or verified.  The location  of  these
              files  can  be  set  using  the  TemporaryDirectory  parameter.   Intended only for
              debugging verification problems.

       KeyFile (string)
              Gives the location of a PEM-formatted private  key  to  be  used  for  signing  all
              messages.  Ignored if a KeyTable is defined.

       KeyTable (dataset)
              Gives  the  location  of  a  file  mapping  key names to signing keys.  If present,
              overrides any KeyFile setting in the configuration file.  The data set  named  here
              maps  each  key  name  to  three  values:  (a) the name of the domain to use in the
              signature's "d=" value; (b) the name of the selector to use in the signature's "s="
              value;  and  (c) either a private key or a path to a file containing a private key.
              If the first value consists solely of a percent sign ("%") character,  it  will  be
              replaced  by the apparent domain of the sender when generating a signature.  If the
              third value starts with a slash ("/") character, or  "./"  or  "../",  then  it  is
              presumed to refer to a file from which the private key should be read, otherwise it
              is itself a PEM-encoded private key or a base64-encoded DER private key; a  "%"  in
              the  third  value  in this case will be replaced by the apparent domain name of the
              sender.  The SigningTable (see below) is used to select records from this table  to
              be used to add signatures based on the message sender.

       LDAPAuthMechanism (string)
              Names  the  authentication mechanism to use when connecting to an LDAP server.  The
              default is the empty string, meaning "simple" authentication should be done.

       LDAPAuthName (string)
              Specifies the authenticating name to use when using SASL to authenticate to an LDAP
              server.   Requires  SASL  support  be  installed  on the local system.  There is no

       LDAPAuthRealm (string)
              Specifies the authentication realm to use when using SASL  to  authenticate  to  an
              LDAP  server.  Requires SASL support be installed on the local system.  There is no

       LDAPAuthUser (string)
              Specifies the authenticating user to use when using SASL to authenticate to an LDAP
              server.   Requires  SASL  support  be  installed  on the local system.  There is no

       LDAPBindPassword (string)
              Specifies the password to use when conducting an LDAP "bind" operation.   There  is
              no default.

       LDAPBindUser (string)
              Specifies the user ID to use when conducting an LDAP "bind" operation.  There is no

       LDAPDisableCache (Boolean)
              Suppresses creation of a local cache in front of LDAP queries.

       LDAPKeepaliveIdle (integer)
              Sets the number of seconds a connection to an LDAP  server  needs  to  remain  idle
              before  TCP  starts  sending  keepalive probes.  If not specified, the LDAP library
              default is used.

       LDAPKeepaliveInterval (integer)
              Sets the interval in seconds between TCP keepalive probes.  If not  specified,  the
              LDAP library default is used.

       LDAPKeepaliveProbes (integer)
              Sets  the  maximum number of keepalive probes TCP should send before abandoning the
              connection.  If not specified, the LDAP library default is used.

       LDAPTimeout (integer)
              Sets the time in seconds after which an LDAP operation should  be  abandoned.   The
              default is 5.

       LDAPUseTLS (Boolean)
              Indicates  whether or not a TLS connection should be established when contacting an
              LDAP server.  The default is "False".

       LogResults (boolean)
              If logging is enabled (see Syslog below), requests that the results  of  evaluation
              of  all signatures that were at least partly intact (i.e., the "d=", "s=", and "b="
              tags could be extracted).

       LogWhy (boolean)
              If logging is enabled (see Syslog below), issues very detailed  logging  about  the
              logic  behind  the  filter's  decision  to either sign a message or verify it.  The
              logic behind the decision is non-trivial and can be confusing to administrators not
              familiar  with  its  operation.   A  description of how the decision is made can be
              found in the OPERATIONS section of the opendkim(8) man page.  This causes  a  large
              increase  in  the  amount  of  log data generated for each message, so it should be
              limited to debugging use and not enabled for general operation.

       MacroList (dataset)
              Defines a set of MTA-provided macros that should be checked to see  if  the  sender
              has  been  determined  to  be a local user and therefore whether or not the message
              should be signed.  If a value is specified matching a macro name in the  data  set,
              the  value  of the macro must match a value specified (matching is case-sensitive),
              otherwise the macro must be defined but may contain any value.  The set is empty by
              default,  meaning  macros  are not considered when making the sign-verify decision.
              The general format of the value is value1[|value2[|...]]; if one or more  value  is
              defined then the macro must be set to one of the listed values, otherwise the macro
              must be set but can contain any value.

              In order for the macro and its value to be available to the  filter  for  checking,
              the MTA must send it during the protocol exchange.  This is either accomplished via
              manual configuration of the MTA to send  the  desired  macros  or,  for  MTA/filter
              combinations that support the feature, the filter can request those macros that are
              of interest.  The latter is a feature negotiated at the time the filter receives  a
              connection  from  the  MTA  and its availability depends upon the version of milter
              used to compile the filter and the version of the MTA making the connection.

              This data set must be of type "file" or "csl".

       MaximumHeaders (integer)
              Defines the maximum number of bytes the header  block  of  a  message  may  consume
              before  the  filter  will  reject  the message.  This mitigates a denial-of-service
              attack in which a client connects to the MTA and begins feeding an unbounded number
              of  header  fields  of arbitrary size; since the filter keeps a cache of these, the
              attacker could cause the filter to allocate an unspecified amount of  memory.   The
              default is 65536; a value of 0 removes the limit.

       MaximumSignaturesToVerify (integer)
              Defines the maximum number of signatures on a message for which verification should
              be conducted.  The default is three.  Signatures are selected from the top  of  the
              message  downward.   If TrustSignaturesFrom is set, signatures from domains in that
              data set are always verified, which may consume part or all  of,  or  even  exceed,
              this limit.

       MaximumSignedBytes (integer)
              Specifies  the  maximum  number  of  bytes  of message body to be signed.  Messages
              shorter than this limit will be signed  in  their  entirety.   Setting  this  value
              implies use of BodyLengthDB for all addresses.

       MilterDebug (integer)
              Sets the debug level to be requested from the milter library.  The default is 0.

       Minimum (string)
              Instructs  the verification code to fail messages for which a partial signature was
              received.  There are three possible formats: min indicating at least min  bytes  of
              the  message  must  be signed (or if the message is smaller than min then all of it
              must be signed); min% requiring that at least min percent of the  received  message
              must  be  signed;  and min+ meaning there may be no more than min bytes of unsigned
              data appended to the message for it to be considered valid.

       MinimumKeyBits (integer)
              Establishes a minimum key size for acceptable signatures.  Signatures with  smaller
              key  sizes, even if they otherwise pass DKIM validation, will me marked as invalid.
              The default is 1024, which accepts all signatures.  A value of 0 causes the default
              to be used.

       Mode (string)
              Selects operating modes.  The string is a concatenation of characters that indicate
              which mode(s) of  operation  are  desired.   Valid  modes  are  s  (signer)  and  v
              (verifier).   The  default is sv except in test mode (see the opendkim(8) man page)
              in which case the default is v.  When signing mode is enabled, one of the following
              combinations  must  also  be  set:  (a)  Domain, KeyFile, Selector, no KeyTable, no
              SigningTable; (b) KeyTable, SigningTable, no Domain, no KeyFile, no  Selector;  (c)
              KeyTable, SetupPolicyScript, no Domain, no KeyFile, no Selector.

       MTA (dataset)
              A  set  of  MTA names (a la the sendmail(8) DaemonPortOptions Name parameter) whose
              mail should be signed by this filter.  There is no default, meaning MTA name is not
              considered when making the sign-verify decision.

       MTACommand (string)
              Specifies  the  path  to  an  executable  to  be used for sending mail such as that
              generated by SendReports.   The  default  is  /usr/sbin/sendmail.   The  executable
              should  accept  typical  sendmail(8) command line options "-t" (take addresses from
              message body) and "-f" (set  envelope  sender),  accept  the  new  message  on  its
              standard input, and return a non-zero exit status on any error.

       MultipleSignatures (Boolean)
              Allow  addition  of  multiple  signatures  when  a  signing  table  is in use.  See
              SigningTable for more information.

       MustBeSigned (dataset)
              Specifies a set of header fields that, if present, must  be  covered  by  the  DKIM
              signature  when  verifying  a message.  If a header field in this set is present in
              the message and is not signed, the  filter  will  treat  even  an  otherwise  valid
              signature as invalid.  The default is an empty list.

       Nameservers (string)
              Provides  a comma-separated list of IP addresses that are to be used when doing DNS
              queries to retrieve DKIM keys, VBR records, etc.  These override any local defaults
              built  in to the resolver in use, which may be defined in /etc/resolv.conf or hard-
              coded into the software.

       NoHeaderB (Boolean)
              If set, this feature suppresses the use of "header.b" tags in added Authentication-
              Results  header  fields.   The  default  is "false", which means those tags will be

       OmitHeaders (dataset)
              Specifies a set of header fields that should be omitted when generating signatures.
              If  an  entry  in  the  list  names  any  header field that is mandated by the DKIM
              specification, the entry is ignored.  A set of header fields is listed in the  DKIM
              specification  (RFC6376,  Section  5.4) as "SHOULD NOT" be signed; the default list
              for  this  parameter  contains  those  fields  (Return-Path,  Received,   Comments,
              Keywords,  Bcc, Resent-Bcc and DKIM-Signature).  To omit no headers, simply use the
              string "." (or any string that will match no header  field  names).   Specifying  a
              list  with this parameter replaces the default entirely, unless one entry is "*" in
              which case the list is  interpreted  as  a  delta  to  the  default;  for  example,
              "*,+foobar" will use the entire default list plus the name "foobar", while "*,-Bcc"
              would use the entire default list except for the "Bcc" entry.

       On-BadSignature (string)
              Selects the action to be taken when a signature fails to validate.  Possible values
              (with abbreviated forms in parentheses): accept (a) accept the message; discard (d)
              discard the message; quarantine (q) quarantine the message; reject (r)  reject  the
              message; tempfail (t) temp-fail the message.  The default is accept.  Note that the
              "t" (testing) flag in a DKIM key bypasses this  behaviour;  a  bad  signature  that
              references a testing flag will still be delivered, though the added Authentication-
              Results field will indicate both the failed  result  and  the  test  mode  so  that
              consumers of the message can take appropriate action.

       On-Default (string)
              Selects  the action to be taken when any verification or internal error of any kind
              is encountered.  This is processed before the other "On-" values so it can be  used
              as a blanket setting followed by specific overrides.

       On-DNSError (string)
              Selects the action to be taken when a transient DNS error is encountered.  Possible
              values are the same as those for On-BadSignature.  The default is tempfail.

       On-InternalError (string)
              Selects the action to be taken when an internal error of some kind is  encountered.
              Possible  values  are  the  same  as  those  for  On-BadSignature.   The default is

       On-KeyNotFound (string)
              Selects the action to be taken when the  key  referenced  by  a  signature  is  not
              present  in  the  DNS.   Possible values are the same as those for On-BadSignature.
              The default is accept.

       On-NoSignature (string)
              Selects the action to be taken when a message arrives  unsigned.   Possible  values
              are the same as those for On-BadSignature.  The default is accept.

       On-Security (string)
              Selects  the  action  to be taken when a message arrives containing properties that
              may be a security  concern.   Possible  values  are  the  same  as  those  for  On-
              BadSignature.  The default is tempfail.

       On-SignatureError (string)
              Selects  the  action  to be taken when a message cannot be signed because of issues
              with the message or the key provided for signing.  Possible values are the same  as
              those for On-BadSignature.  The default is reject.

       OversignHeaders (dataset)
              Specifies  a  set  of header fields that should be included in all signature header
              lists (the "h=" tag) once more than the number of times they were actually  present
              in  the  signed  message.   The  set is empty by default.  The purpose of this, and
              especially of listing an absent  header  field,  is  to  prevent  the  addition  of
              important  fields  between  the  signer and the verifier.  Since the verifier would
              include that header field when performing verification if it had been added  by  an
              intermediary,  the  signed  message and the verified message were different and the
              verification would fail.  Note that listing a field name here and not listing it in
              the SignHeaders list is likely to generate invalid signatures.

       PeerList (dataset)
              Identifies  a  set  of  "peers" that identifies clients whose connections should be
              accepted without processing by this filter.  The set should contain on each line  a
              hostname, domain name (e.g. ""), IP address, an IPv6 address (including
              an IPv4 mapped address), or a CIDR-style IP specification (e.g.  "").
              An  entry beginning with a bang ("!") character means "not", allowing exclusions of
              specific hosts that are otherwise members of larger sets.  Host  and  domain  names
              are  matched  first,  then the IP or IPv6 address depending on the connection type.
              More precise entries are preferred over less precise ones, i.e.  "" will
              match  before "!".  The text form of IPv6 addresses will be forced to
              lowercase when queried (RFC5952), so the contents of this data set should also  use
              lowercase.   The  IP  address  portion  of  an  entry may optionally contain square
              brackets; both forms (with and without) will be checked.

       PidFile (string)
              Specifies the path to a file that should be created at process start containing the
              process ID.

       POPDBFile (dataset)
              Requests  that the filter consult a set for IP addresses that should be allowed for
              signing. This feature was designed for POP-before-SMTP  datastores.   (Not  enabled
              for this installation.)

       Quarantine (Boolean)
              Requests  that  messages  which  fail  verification  be  quarantined  by  the  MTA.
              (Requires a sufficiently recent version of the milter library.)

       QueryCache (Boolean)
              Instructs the DKIM library to maintain its own local cache  of  keys  and  policies
              retrieved  from  DNS,  rather  than  relying on the nameserver for caching service.
              Useful if the nameserver being used by the filter is not local.

       RedirectFailuresTo (address)
              Messages bearing signatures that failed to verify are redirected to  the  specified
              address.   The  original  envelope  recipient  set is recorded in the header before
              redirection occurs.  By default, no redirection is done.

       RemoveARAll (Boolean)
              Removes  all  Authentication-Results:  header  fields   that   also   satisfy   the
              requirements  of  RemoveARFrom  below.   By  default,  only those containing a DKIM
              result are removed.

       RemoveARFrom (dataset)
              Defines a set of hostnames whose Authentication-Results: header  fields  should  be
              removed  before  the  message is passed for delivery.  By default only those header
              fields matching the local host's canonical name will be removed.  Matching is  only
              done  on  full  hostnames  (e.g.  "")  or  on  domain  names  (e.g.

       RemoveOldSignatures (Boolean)
              Removes all existing signatures when operating in signing mode.

       ReplaceHeaders (data set)
              Defines a set of header fields that should be  affected  by  the  text  replacement
              rules  defined  by  the  ReplaceRules  setting.   By default, all header fields are
              included.  (Note: Feature is experimental.)

       ReplaceRules (string)
              Specifies a file containing a list of text replacement rules that  are  applied  to
              the  message header fields to replace certain content expected to be changed as the
              message passes through local MTAs.   This  can  be  used  to  accommodate  expected
              changes  such as are made to From: fields by MTA "masquerade" features.  Each entry
              in the file consists of a POSIX regular expression, followed by a  tab  (ASCII  9),
              followed  by  the  text  that  should  be  used  to  replace  the text matching the
              expression.  The '#' character denotes the beginning of a  comment  and  text  from
              that  point  on in a single line is ignored.  Blank lines are also skipped.  (Note:
              Feature is experimental.)

       ReportAddress (string)
              Specifies the string to use in the From: header field  for  outgoing  reports  (see
              SendReports  below).   If not specified, the executing user and local hostname will
              be used to construct the address.

       ReportBccAddress (string)
              Specifies address(es) to include in a Bcc: header field on  outgoing  reports  (see
              SendReports  below).  If  multiple  addresses  are  required,  they should be comma

       RequestReports (boolean)
              When  signing,  includes  a  request  for  signature  evaluation  failures  in  the
              signature.  (See RFC6651 for details.)

       RequiredHeaders (boolean)
              Checks  all  messages  for compliance with RFC5322 header field count requirements.
              Non-compliant messages are rejected.

       RequireSafeKeys (boolean)
              When reading a key file, a message will be logged if the key file has the  read  or
              write bit set other than for the owner or for a group that the executing process is
              in.  With this feature set to "true", the filter  will  further  consider  this  an
              error and refuse to make use of the file's contents.  The default is "true".

       ResignAll (boolean)
              Where ResignMailTo triggers a re-signing action, this flag indicates whether or not
              all mail should be signed (if set) versus only verified mail being signed  (if  not
              set).   The  default  is  "false".   (Experimental  feature  not  enabled  for this

       ResignMailTo (dataset)
              Checks each message recipient against the specified dataset for a matching  record.
              The  full  address  is  checked  in  each case, then the hostname, then each domain
              preceded by ".".  If there is a match, the value returned is  presumed  to  be  the
              name  of  a  key  in the KeyTable (if defined) to be used to re-sign the message in
              addition to verifying it.  If there is a match without a KeyTable, the default  key
              is applied.  (Experimental feature not enabled for this installation.)

       ResolverConfiguration (string)
              Provides  the given string as configuration information to the underlying resolver.
              For the standard UNIX resolver, this is unused; for Unbound, the string contains  a
              filename that is considered to be a configuration file.  There is no default.

       ResolverTracing (Boolean)
              Requests  resolver  tracing  features be enabled, if available.  The effect of this
              depends on how debugging features of the resolver might be implemented.   Currently
              only effective with the OpenDKIM asynchronous resolver library.

       ScreenPolicyScript (string)
              Gives  the  name  of a Lua script that should be run after all of the header fields
              have been processed for a message; in particular, this is  useful  after  all  DKIM
              signatures have been detected and initial evaluation has been done.  The script has
              access to all of the header fields and connection information and can that  certain
              signatures be ignored based on that information.  See opendkim-lua(3) for details.

       SelectCanonicalizationHeader (string)
              Defines  a header field name which, if present, adjusts which canonicalization will
              be used to generate an outgoing signature.  Overrides the Canonicalization  setting
              if the header field is present.  The default is "X-Canonicalization".

       Selector (string)
              Defines  the  name  of the selector to be used when signing messages.  See the DKIM
              specification for details.  Used only when signing  with  a  single  key;  see  the
              SigningTable parameter below for more information.

              This parameter is ignored if a KeyTable is defined.

       SenderHeaders (dataset)
              Specifies an ordered list of header fields that should be searched to determine the
              sender of a message.  The first header field found is the one whose value is  used.
              This is mainly used when signing for deciding which signing request(s) to make.  By
              default, the "From" header field is the only  one  checked.   See  the  OmitHeaders
              setting for a description of possible values.

       SenderMacro (string)
              Use the milter macro string to determine the sender of the message.  (Note: Feature
              is experimental.)

       SendReports (Boolean)
              If true, when a signature verification fails and the signature included a reporting
              request  ("r=y")  and  the  signing  domain  advertises  a  reporting address (i.e.
              ra=user) in a reporting record in the DNS, the filter will send a structured report
              to  that  address  containing details needed to reproduce the problem.  See RFC6651
              for a complete description of this mechanism.

       SetupPolicyScript (string)
              Gives the name of a Lua script that should be run once  all  header  fields  for  a
              message  have  arrived.   The  script  has  access  to all of the header fields and
              connection information and can request DKIM verification or signing based  on  that
              information.  See opendkim-lua(3) for details.

       SignatureAlgorithm (string)
              Selects the signing algorithm to use when generating signatures.  Use 'opendkim -V'
              to see the list of supported algorithms.   The  default  is  rsa-sha256  if  it  is
              available, otherwise it will be rsa-sha1.

       SignatureTTL (integer)
              Sets  the  time-to-live, in seconds, of signatures generated by the filter.  If not
              set, no expiration time is added to signatures.

       SignHeaders (dataset)
              Specifies the set  of  header  fields  that  should  be  included  when  generating
              signatures.   If  the  list  omits  any  header  field that is mandated by the DKIM
              specification, those fields are implicitly added.  By default, those fields  listed
              in  the  DKIM  specification  as  "SHOULD" be signed (RFC6376, Section 5.4) will be
              signed  by  the  filter.   See  the  OmitHeaders  configuration  option  for   more
              information about the format and interpretation of this field.

       SigningTable (dataset)
              Defines  a  table used to select one or more signatures to apply to a message based
              on the address found in the From: header field.  Keys in this table vary  depending
              on  the  type  of table used; values in this data set should include one field that
              contains a name found in the KeyTable (see above) that identifies which key  should
              be used in generating the signature, and an optional second field naming the signer
              of the message that will be included in the "i=" tag in  the  generated  signature.
              Note that the "i=" value will not be included in the signature if it conflicts with
              the signing domain (the "d=" value).

              If the first field contains only a "%" character, it will be replaced by the domain
              found  in the From: header field.  Similarly, within the optional second field, any
              "%" character will be replaced by the domain found in the From: header field.

              If this table specifies a regular expression file ("refile"),  then  the  keys  are
              wildcard  patterns  that  are matched against the address found in the From: header
              field.  Entries are checked in the order in which they appear in the file.

              For all other database types, the full user@host  is  checked  first,  then  simply
              host,   then   user@.domain   (with   all  superdomains  checked  in  sequence,  so
              ""    would     first     check     "",     then
              "", then ""), then .domain, then user@*, and finally *.

              In  any case, only the first match is applied, unless MultipleSignatures is enabled
              in which case all matches are applied.

       SMTPURI (string)
              Specifies a URI (e.g., "smtp://localhost") to which mail should be  sent  via  SMTP
              when notifications are generated.  (Not enabled for this installation.)

       Socket (string)
              Specifies  the  socket  that  should  be  established  by  the  filter  to  receive
              connections from sendmail(8) in order to provide service.  socketspec is in one  of
              two forms: local:path, which creates a UNIX domain socket at the specified path, or
              inet:port[@host] or inet6:port[@host] which creates a TCP socket on  the  specified
              port  and  in  the specified protocol family.  If the host is not given as either a
              hostname or an IP address, the socket will  be  listening  on  all  interfaces.   A
              literal  IP  address must be enclosed in square brackets.  This option is mandatory
              either in the configuration file or on the command line.

       SoftStart (Boolean)
              If set, the inability to connect and authenticate to an LDAP or SQL server will not
              prevent  the  filter  from  starting,  and reconnections will be attempted for each
              query.  The default is "False".

       SoftwareHeader (Boolean)
              Causes opendkim to add an "DKIM-Filter" header field  indicating  the  presence  of
              this  filter  in the path of the message from injection to delivery.  The product's
              name, version, and the job ID are included in the header  field's  contents.   Note
              that  the  header  field  is not added if the Mode setting causes the message to be
              ignored (e.g., if only signing mode is enabled and  the  configuration  causes  the
              message  not  to  be signed, or only verify mode is enabled and configuration would
              otherwise have caused the message to be signed, then it will not have  this  header
              field added).

       Statistics (filename)
              This specifies a file in which to store DKIM transaction statistics.  See opendkim-
              stats(8) for a mechanism to parse the file's contents,  and  opendkim-importstats()
              for  a  mechanism  to  translate  the file's contents into SQL database insertions.
              (Note: Feature is experimental.)

       StatisticsName (string)
              Defines the name to be used as the reporting host in statistics logs.  By  default,
              the  local  host's  name  returned  by  gethostname(3)  is used.  (Note: Feature is

       StatisticsPrefix (string)
              When AnonymousStatistics is enabled, this string  may  be  specified  and  will  be
              prepended  to  all data before hashing for more complete anonymization.  This means
              two records from different sources referencing the same source will  still  produce
              different  hashes,  meaning  such  correlation is now only possible within the data
              from a single repoter.

       StrictHeaders (Boolean)
              If set, instructs the DKIM library to refuse processing of a message if the  header
              field count does not conform to RFC5322 Section 3.6.

       StrictTestMode (Boolean)
              Selects  strict  CRLF  mode  during  testing  (see  the -t command line flag in the
              opendkim(8) man page); messages for which all header fields and body lines are  not
              CRLF-terminated are considered malformed and will produce an error.

       SubDomains (Boolean)
              Sign  subdomains  of  those  listed  by  the Domain parameter as well as the actual

       Syslog (Boolean)
              Log via calls to syslog(3) any interesting activity.

       SyslogFacility (string)
              Log via calls to syslog(3) using the named facility.  The facility  names  are  the
              same as the ones allowed in syslog.conf(5).  The default is "mail".

       SyslogSuccess (Boolean)
              Log  via  calls  to  syslog(3)  additional entries indicating successful signing or
              verification of messages.

       TemporaryDirectory (string)
              Specifies the  directory  in  which  temporary  canonicalization  files  should  be
              written.  The default is to use the libdkim default location, currently /tmp.

       TestDNSData (data set)
              Provides  a  data  set whose keys will be treated as DNS record names and values as
              TXT record contents.  Intended for use during automated testing.

       TestPublicKeys (string)
              Names a file from which public keys should be read.  Intended for use  only  during
              automated testing.

       TrustAnchorFile (string)
              Specifies a file from which trust anchor data should be read when doing DNS queries
              and applying the DNSSEC protocol.  This is currently ignored unless the  underlying
              library  is compiled to use Unbound; see the documentation at at
              for the expected format of this file.

       TrustSignaturesFrom (dataset)
              This value consists of a set of domains that are considered trustworthy in terms of
              third-party  signatures.   That  is,  if  a message arrives with a signature from a
              domain that doesn't match the domain in the From: header, this  setting  determines
              whether  or  not  that  signature will be trusted.  If this value is undefined, all
              signatures are trusted.

       UMask (integer)
              Requests a specific permissions mask to be  used  for  file  creation.   This  only
              really  applies  to  creation  of  the  socket  when Socket specifies a UNIX domain
              socket, and to the PidFile (if any); temporary files are created by the  mkstemp(3)
              function  that  enforces a specific file mode on creation regardless of the process
              umask.  See umask(2) for more information.

       UnprotectedKey (string)
              Instructs the filter to treat a passing signature associated with a key found in an
              insecure  (i.e.  not  protected  by  DNSSEC) DNS record in a special way.  Possible
              values are neutral (return a "neutral" result), none (take no special action;  this
              is the default) and fail (return a "fail" result).

       UserID (string)
              Attempts  to  become the specified userid before starting operations.  The value is
              of the form userid[:group].  The process will be assigned all  of  the  groups  and
              primary group ID of the named userid unless an alternate group is specified.

       VBR-Certifiers (string)
              The  default  certifiers if not specified in X-VBR-Certifiers header field.  (Note:
              Feature is experimental.)

       VBR-PurgeFields (string)
              If set, arranges to remove X-VBR-Certifiers and X-VBR-Type fields on messages prior
              to sending them.  (Note: Feature is experimental.)

       VBR-TrustedCertifiers (string)
              A  colon or comma sparated list of trusted certifiers to accept when verifying VBR-
              Info header field.  (Note: Feature is experimental.)

       VBR-TrustedCertifiersOnly (Boolean)
              By default, the certifiers that are in both the trusted certifiers list (above) and
              those  in  the  message's VBR-Info header field will be checked for vouching.  With
              this option set, the trusted certifiers will be checked and the ones claimed by the
              message will be ignored.  (Note: Feature is experimental.)

       VBR-Type (string)
              This  default  VBR  type  if  not specified in the X-VBR-Type header field.  (Note:
              Feature is experimental.)

       WeakSyntaxChecks (Boolean)
              Requests that the library continue processing messages even if  syntax  errors  are
              discovered  early  in  message  analysis.   This  means, for example, that a signed
              message with a mangled From: field will still proceed to verification even  if  the
              author's domain could not be determined.


       When  using  DNS  timeouts (see the DNSTimeout option above), be sure not to use a timeout
       that is larger than the timeout being  used  for  interaction  between  sendmail  and  the
       filter.   Otherwise,  the  MTA  could  abort  a message while waiting for a reply from the
       filter, which in turn is still waiting for a DNS reply.

       Features that involve specification  of  IPv4  addresses  or  CIDR  blocks  will  use  the
       inet_addr(3)  function  to  parse that information.  Users should be familiar with the way
       that function handles the non-trivial cases (for example, "192.0.2/24" and  ""
       are not the same thing).


              Default location of this file.


       This man page covers version 2.11.0 of opendkim.


       Copyright (c) 2007, 2008, Sendmail, Inc. and its suppliers.  All rights reserved.

       Copyright (c) 2009-2015, The Trusted Domain Project.  All rights reserved.


       opendkim(8), opendkim-lua(3), sendmail(8)

       RFC5451 - Message Header Field for Indicating Message Authentication Status

       RFC5617 - DKIM Author Domain Signing Practises

       RFC5965 - An Extensible Format for Email Feedback Reports

       RFC6008  -  Authentication-Results  Registration  for  Differentiating among Cryptographic

       RFC6376 - DomainKeys Identified Mail

       RFC6651 - Extensions to DomainKeys Identified Mail (DKIM) for Failure Reporting

                                    The Trusted Domain Project                   opendkim.conf(5)