Provided by: opendkim_2.5.2+dfsg-1ubuntu3_amd64 bug

NAME

       opendkim.conf - Configuration file for opendkim

LOCATION

       /etc/opendkim.conf

DESCRIPTION

       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.

PARAMETERS

       AddAllSignatureResults (Boolean)
              If "true", results for all signatures will be reported by an added  Authentication-
              Results  header  field.   Otherwise, only one signature will be reported, and which
              one depends on the TrustSignaturesFrom setting or, in  its  absence,  which  one(s)
              passed  first  or,  if  none  passed,  which  one  was  found  first during message
              processing.

       ADSPAction (string)
              Selects the action to be taken when an ADSP check against a message with  no  valid
              author  signature  results  in the message being deemed suspicious and discardable.
              Possible values are "discard" (accept the mesasge but throw it away)  and  "reject"
              (bounce the message).  If not set, discardable messages will still be delivered.

       ADSPNoSuchDomain (Boolean)
              If  "true",  requests  rejection  of  messages  that  are  determined  to  be  from
              nonexistent domains according to the author domain signing practises (ADSP) test.

       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.

       AlwaysSignHeaders (dataset)
              Specifies  a  set  of header fields that should be included in all signature header
              lists (the "h=" tag) even if they were not present at the time  the  signature  was
              generated.   The  set is empty by default.  The purpose of listing an absent header
              field is to prevent its addition between the signer and  the  verifier,  since  the
              verifier  would  include  that  header  field  if  it  were  added  when performing
              verification, which would mean the signed message and  the  verified  message  were
              different and the verification would fail.

       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
              default.

       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)
              Normally  opendkim  forks and exits immediately, leaving the service running in the
              background.  This flag suppresses that behaviour so that it runs in the foreground.

       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
              default).

       BogusPolicy (string)
              Instructs  the filter to treat an ADSP policy found in an bogus (forged) DNS record
              in a special way.  Possible values are apply (apply the policy) and ignore  (ignore
              the policy; this is the default).

       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
              generated.

       DisableADSP (Boolean)
              If set, suppresses Author Domain Signing Practices  (ADSP)  checks,  which  require
              multiple additional DNS queries.

       DKIMReputationFail (integer)
              If  the  reputation  returned by the DNS reputation service exceeds this value then
              the result "x-dkim-rep" is set to "fail".  Defaults to  0.   (Experimental  feature
              not enabled for this installation.)

       DKIMReputationPass (integer)
              If  the  reputation  returned by the DNS reputation service is less than this value
              then the result "x-dkim-rep" is set to "pass".  Defaults to 0.  Values  in  between
              DKIMReputationFail  and  DKIMReputationPass  result  in  "x-dkim-rep"  being set to
              "neutral".  (Experimental feature not enabled for this installation.)

       DKIMReputationReject (integer)
              If the reputation returned by the DNS reputation service exceeds  this  value  then
              the message is rejected.  The default value here is 1001, a deliberately impossible
              value so that rejections are not enabled by  default.   (Experimental  feature  not
              enabled for this installation.)

       DKIMReputationRoot (string)
              This is the root directory of the DNS reputation service.  Its interface is defined
              at  http://www.dkim-reputation.org.   The   default   value   here   is   "al.dkim-
              reputation.org".   A value of "none" disables the check.  (Experimental feature not
              enabled for this installation.)

       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
              "false".

       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.   Basically  suppresses  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.)

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

       InsecureKey (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).

       InsecurePolicy (string)
              Instructs  the  filter  to  treat  an  ADSP  policy found in an insecure (i.e.  not
              protected by DNSSEC) DNS record in a special way.  Possible values are apply (apply
              the policy; this is the default) and ignore (ignore the policy).

       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  "127.0.0.1" is applied.  Naturally,
              providing a value here overrides the default, so if mail from 127.0.0.1  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
              forgery).

       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
              default.

       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
              default.

       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
              default.

       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
              default.

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

       LocalADSP (dataset)
              Allows specification of local ADSP overrides for domains.  This is expected to be a
              data set with keys and matching values; the keys are each either a  fully-qualified
              domain name (e.g. "foo.example.com") or a subdomain name preceded by a period (e.g.
              ".example.com"), and the values are either unknown, all, or discardable, as per the
              ADSP  specification  (RFC5617).  This allows local overrides of policies to enforce
              for domains that either don't publish ADSP or  publish  weaker  policies  than  the
              verifier would like to enforce.

       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.  Note that this could cause an author domain signature to  be  ignored,
              causing  the  ADSP  evaluation  to  fail  and,  if  SendADSPReports  is  enabled, a
              questionable report could be generated.

       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.

       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 SendADSPReports and 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.

       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
              applied.

       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.

       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
              tempfail.

       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-PolicyError (string)
              Selects the action to be taken when a an  attempt  to  retrieve  and  evaluate  the
              author  domain's  signing  policy  (ADSP) is unsuccessful.  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.

       OversignHeaders (dataset)
              Specifies a set of header fields that should be included in  all  signature  header
              lists  (the  "h="  tag)  even  if  they  were present at the time the signature was
              generated.  The set is empty by default.  The purpose of listing an  absent  header
              field  is  to  prevent  its addition between the signer and the verifier, since the
              verifier would  include  that  header  field  if  it  were  added  when  performing
              verification,  which  would  mean  the signed message and the verified message were
              different and the verification would fail.  Unlike AlwaysSignHeaders, the names  in
              this  data  set  are  always  added  to  signatures  even if they did appear in the
              original header field set.  Note that the fields in this list must also be  present
              in  the SignHeaders list, or any signature produced will be impossible to validate.
              (Experimental feature not enabled for this installation.)

       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. ".example.com"), IP address, an IPv6 address (including
              an  IPv4 mapped address), or a CIDR-style IP specification (e.g. "192.168.1.0/24").
              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.  "192.168.1.1" will
              match before "!192.168.1.0/24".  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.

       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.  (Not  enabled  for
              this installation.)

       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.  "host.example.com")  or  on  domain  names  (e.g.
              ".example.com").

       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 accomodate 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 and SendADSPReports 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 and SendADSPReports below). If multiple addresses  are  required,  they
              should be comma separated.

       RequestReports (boolean)
              When  signing,  includes  a  request  for  signature  evaluation  failures  in  the
              signature.   (See  draft-ietf-marf-dkim-reporting  for   details.)    (Experimental
              feature not enabled for this installation.)

       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
              installation.)

       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.)

       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.

       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.

       SelectorHeader (string)
              Names  a  header  field  whose  contents  name  the  key  to use when signing.  The
              referenced key must appear in the KeyTable.  (Note: Feature is experimental.)

       SelectorHeaderRemove (Boolean)
              Remove the SelectorHeader before signing.  (Note: Feature is experimental.)

       SendADSPReports (Boolean)
              If true, when a policy evaluation fails and the signing site advertises a reporting
              address  (i.e.   r=user  in  its  policy  record) and a request for reports of such
              failures, the filter will send a  structured  report  to  that  address  containing
              details of the incident.

       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 verifying a message to determine the origin domain (for
              policy checks), and when signing for deciding which signing request(s) to make.  By
              default,  the  DKIM  library's  internal list is used, which consists solely of the
              "From" header field.  See the OmitHeaders setting for  a  description  of  possible
              values.

       SenderMacro (string)
              Use  the milter macro string to determine the sender of the message.  (Experimental
              feature not enabled for this installation.)

       SendReports (Boolean)
              If true, when a signature verification fails and  the  signing  site  advertises  a
              reporting  address (i.e.  r=user in its policy record) and a request for reports of
              such failures, the filter will send a structured report to that address  containing
              details needed to reproduce the problem.

       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.

              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
              "foo.example.com"     would     first     check     "user@foo.example.com",    then
              "user@.example.com", then "user@.com"), 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.

       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], which creates a TCP socket on the specified port.  If the host is
              not  given  as  either a hostname or an IP address, the socket will be listening on
              all interfaces.  This option is mandatory either in the configuration  file  or  on
              the command line.

       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
              experimental.)

       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
              domains.

       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 /var/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.    See   the   Unbound   documentation   at
              http://unbound.net 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.

       UnboundConfigFile (string)
              Specifies  a  configuration  file to be passed to the Unbound library that performs
              DNS queries applying  the  DNSSEC  protocol.   See  the  Unbound  documentation  at
              http://unbound.net  for  the  expected  content of this file.  The results of using
              this and the TrustAnchorFile setting at the same time are undefined.

       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.
              (Experimental feature not enabled for this installation.)

       VBR-PurgeFields (string)
              If set, arranges to remove X-VBR-Certifiers and X-VBR-Type fields on messages prior
              to sending them.  (Experimental feature not enabled for this installation.)

       VBR-TrustedCertifiers (string)
              A colon or comma sparated list of trusted certifiers to accept when verifying  VBR-
              Info header field.  (Experimental feature not enabled for this installation.)

       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.  (Experimental feature not enabled for this installation.)

       VBR-Type (string)
              This  default  VBR  type  if  not  specified  in  the  X-VBR-Type   header   field.
              (Experimental feature not enabled for this installation.)

       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, which makes later ADSP checks impossible.

       X-Header (Boolean)
              Causes opendkim to add an "X-DKIM" 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).

NOTES

       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 "192.0.2.0/24"
       are not the same thing).

FILES

       /etc/opendkim.conf
              Default location of this file.

VERSION

       This man page covers version 2.5.2 of opendkim.

COPYRIGHT

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

       Copyright (c) 2009-2012, The OpenDKIM Project.  All rights reserved.

SEE ALSO

       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
       Results

       RFC6376 - DomainKeys Identified Mail

                                       The OpenDKIM Project                      opendkim.conf(5)