Provided by: postfix-policyd-spf-python_1.2-1_all bug

NAME

       python-policyd-spf - pure-Python Postfix policy daemon for SPF checking

VERSION

       1.1.1

USAGE

       Usage:
         policyd-spf [/etc/postfix-policyd-spf-python/policyd-spf.conf]

OTHER DOCUMENTATION

       This documentation assumes you have read Postfix's README_FILES/ SMTPD_POLICY_README and
       are generally familiar with Sender Policy Framework (SPF).  See RFC 4408 for details.

       man 1 policyd-spf provides general operation documentation for this package.

       man 5 policyd-spf.peruser provides documentation on setting up and using different
       configuration options on a per user (mail reciepient) basis.

SYNOPSIS

       python-policyd-spf operates with a default installed configuration file and set of default
       configuration options that are used if the configuration file cannot be found.  These
       options can be changed by changing the installed configuration files or through giving a
       path to an alternate configuration file.

DESCRIPTION

       Configuration options are described here and in the configuration file provided with the
       package.  The provided setup.py installs this configuration file in /etc/postfix-policyd-
       spf-python/.

       Additionally, whitelisting certain IP addresses from SPF checks is supported.  This man
       page and the sample configuration file show the format to use.  These options can be
       adjusted on a per user (mail recipient) basis.  Details on per user settings can be found
       in policyd-spf.peruser(5).

OPTIONS

LOGGING

       "debugLevel" controls the amount of information logged by the policy server.

       The default, 1, logs no debugging messages, just basic SPF results and errors generated
       through the policy server.  This value can be increased up to 5 (values higher than 5 will
       not cause an error, but will not log any additional information).

       debug level 2 adds a log message if no client address (IP address from which the
       connection was made), Mail From addresss, or HELO/EHLO name is received by the policy
       server, and logs SPF results for each Mail From and HELO check.

       debug level 3 generates a log message each time the policy server starts and each time it
       exits, as well as logging a copy of the exact header returned to Postfix to be prepended
       into the message.  Each time the policy server starts, debug level 3 also logs the
       configuration information used by the policy server.

       debug level 4 logs the complete data set received by Postfix via the policy interface and
       when the end of the entry is read.

       debug level 5 is used to debug config file processing and can only be set in code and not
       via the config file.

       If debug level is 0, then the policy server logs errors only.

       Default:

       debugLevel = 1

TEST OPERATION

       The policy server can operate in a test only mode. This allows you to see the potential
       impact of SPF checking in your mail logs without rejecting mail.  Headers are prepended in
       messages, but message delivery is not affected. This mode is not enabled by default.  To
       enable it, set defaultSeedOnly = 0.

       Default:

       defaultSeedOnly = 1

HELO/EHLO CHECKING

       HELO check rejection policy options are:

       SPF_Not_Pass (default) - Reject if result not Pass, None, or Temperror (alternatively put,
       reject if the SPF result is Fail, Softfail, Neutral, PermError). Unlike Mail From
       checking, there are no standard e-mail use cases where a HELO check should not Pass if
       there is an SPF record for the HELO name (transparent forwarding, for example, is not an
       issue). Technically this option is not fully RFC 4408 compliant since the SPF check for
       the Mail From identity is mandatory and Neutral and None results must be treated the same.
       HELO/EHLO is known first in the SMTP dialogue and there is no practical reason to waste
       resources on Mail From checks if the HELO check will already cause the message to be
       rejected. These deviations should not cause interoperability problems when used for HELO.

       Softfail - Reject on HELO Softfail or Fail.  Technically this option is not fully RFC 4408
       compliant since the Mail From identity is mandatory, but HELO/ EHLO is known first in the
       SMTP dialogue and there is no practical reason to waste resources on Mail From checks if
       the HELO check will already cause the message to be rejected.

       Fail - Reject only on HELO Fail.  Technically this option is not fully RFC 4408 compliant
       since the Mail From identity is mandatory, but HELO/EHLO is known first in the SMTP
       dialogue and there is no practical reason to waste resources on Mail From checks if the
       HELO check will already cause the message to be rejected.

       Null - Only reject HELO Fail for Null sender (SPF Classic).  This is the approach used by
       the pre-RFC 4408 reference implementation and many of the pre- RFC specifications.  Use of
       at least this option (SPF_Not_Pass or Fail) are preferred) is highly recommended.

       False - Never reject on HELO, append header only. This is useful for post-SMTP spam
       filters such as SpamAssassin.

       No_Check - Never check HELO.  This is only recommended if you are calling the policy
       server twice (once for HELO checks and once for Mail From) with two different
       configuration files.  This approach is useful to get both the HELO and Mail From headers
       prepended to a message.

       Default:

       HELO_reject = SPF_Not_Pass

HELO/EHLO PASS RESTRICTION

       HELO Pass Restriction allows integration with other Postfix access controls by provding a
       user supplied name of a postfix access restriction to be applied to a message when the
       HELO checking result is Pass.  The indicated restriction must be an action as defined for
       a Postfix SMTP server access table access(5) and explained in the Postfix RESTRICTION
       CLASS README. The README.per_user_whitelisting file provided with this distribution
       provides examples. Note: A helo pass restriction will be the returned result even if the
       mail from result would cause the message to be rejected.

       Example:

       HELO_pass_restriction = helo_passed_spf

       Default:

       None

Mail From CHECKING

       Mail From rejection policy options are:

       SPF_Not_Pass - Reject if result not Pass/None/Tempfail. This option is not RFC 4408
       compliant since the mail with an SPF Neutral result is treated differently than mail with
       no SPF record and Softfail results are not supposed to cause mail rejection.  Global use
       of this option is not recommended. Use per-domain if needed (per-domain usage described
       below).

       Softfail - Reject on HELO Softfail or Fail.  Technically this option is not fully RFC 4408
       compliant since Softfail results are not supposed to cause mail rejection.  Global use of
       this option is not recommended. Use per-domain if needed (per-domain usage described
       below).

       Fail (default) - Reject on Mail From Fail.

       False - Never reject on Mail From, append header only.  This is useful for post-SMTP spam
       filters such as SpamAssassin.

       No_Check - Never check Mail From/Return Path.  This is only recommended if you are calling
       the policy server twice (once for HELO checks and once for Mail From) with two different
       configuration files.  This approach is useful to get both the HELO and Mail From headers
       prepended to a message.  It could also be used to do HELO checking only (because HELO
       checking has a lower false positive risk than Mail From checking), but this approach would
       not be fully RFC 4408 compliant since the Mail From identity is mandatory.

       Default:

       Mail_From_reject = Fail

Mail From PASS RESTRICTION

       Mail From Pass Restriction allows integration with other Postfix access contlols by
       provding a user supplied name of a postfix access restriction to be applied to a message
       when the HELO checking result is Pass.  The indicated restriction must be an action as
       defined for a Postfix SMTP server access table access(5) and explained in the Postfix
       RESTRICTION CLASS README. Note: A mail from pass restriction will be the returned result
       even if the helo result would cause the message to be rejected.

       Example:

       mail_from_pass_restriction = mfrom_passed_spf

       Default:

       None

Limit Rejections To Domains That Send No Mail

       No_Mail - Only reject when SPF indicates the host/domain sends no mail. This option will
       only cause mail to be rejected if the HELO/Mail From record is "v=spf1 -all".  This option
       is useful for rejecting mail in situations where the tolerance for rejecting wanted mail
       is very low. It operates on both HELO and Mail From identities if set.

       Default:

       No_Mail = False

Domain Specific Receiver Policy

       Using this option, a list of domains can be defined for special processing when messages
       do not Pass SPF.  This can be useful for commonly spoofed domains that are not yet
       publishing SPF records with -all.  Specifically, if mail from a domain in this list has a
       Neutral/Softfail result, it will be rejected (as if it had a Fail result).  This option is
       not supported by RFC 4408, but if needed, it is better to do it on a per-domain basis
       rather than globally.

       Example:

       Reject_Not_Pass_Domains = aol.com,hotmail.com

       Default:

       None

Permanent Error Processing

       Policy for rejecting due to SPF PermError options are:

       True - Reject the message if the SPF result (for HELO or Mail From) is PermError.  This
       has a higher short-term false positive risk, but does result in senders getting feedback
       that they have a problem with their SPF record.

       False - Treat PermError the same as no SPF record at all.  This is consistet with the pre-
       RFC usage (the pre-RFC name for this error was "Unknown").

       This is a global option that affects both HELO and Mail From scopes when checks for that
       scope are enabled. The only per scope setting that can over-ride this is
       Mail_From/HELO_reject = False/

       Default:

       PermError_reject = False

Temporary Error Processing

       Policy for deferring messages due to SPF TempError options are:

       True - Defer the message if the SPF result (for HELO or Mail From) is TempError.  This is
       the traditional usage and has proven useful in reducing acceptance of unwanted messages.
       Sometimes spam senders do not retry.  Sometimes by the time a message is retried the
       sending IP has made it onto a DNS RBL and can then be rejected.  This is not the default
       because it is possible for some DNS errors that are classified as "Temporary" per RFC 4408
       to be permanent in the sense that they require operator intervention to correct.

       This is a global option that affects both HELO and Mail From scopes when checks for that
       scope are enabled. The only per scope setting that can over-ride this is
       Mail_From/HELO_reject = False/

       False - Treat TempError the same as no SPF record at all.  This is the default to minimize
       false positive risk.

       Default:

       TempError_Defer = False

Prospective SPF Check

       Prospective SPF checking - Check to see if mail sent from the defined IP address would
       pass.  This is useful for outbound MTAs to avoid sending mail that would Fail SPF checks
       when received.  Disable HELO checking when using this option.  It's only potentially
       useful for Mail From checking. SPF Received headers are not added when this option is
       used.

       Prospective = 192.168.0.4

       Default:

       None

LOCAL SPF BYPASS LIST

       Do not check SPF for localhost addresses - add to skip addresses to skip SPF for internal
       networks if desired. Defaults are standard IPv4 and IPv6 localhost addresses. This can
       also be used, to allow mail from local clients submitting mail to an MTA also acting as a
       Mail Submission Agent (MSA) to be skipped.  An x-header is prepended indicating SPF checks
       were skipped due to a local address.  This is a trace header only.  Note the lack of
       spaces in the list.

       Default:

       skip_addresses = 127.0.0.0/8,::ffff:127.0.0.0/104,::1

SPF IP WHITELIST

       A comma separated CIDR Notation list of IP addresses to skip SPF checks for.  Use this
       list to whitelist trusted relays (such as a secondary MX and trusted forwarders).  An x-
       header is prepended indicating the IP was whitelisted against SPF checks.  This is a trace
       header only.  Note the lack of spaces in the list.

       Example:

       Whitelist = 192.168.0.0/31,192.168.1.0/30

       Default:

       None

SPF DOMAIN WHITELIST

       Domain_Whitelist: List of domains whose sending IPs should be whitelisted from SPF checks.
       Use this to list trusted forwarders by domain name.  Client IP addresses are tested
       against SPF records published by the listed domains.  This is useful for large forwarders
       with complex outbound infrastructures and SPF records.  This option is less scalable than
       the SPF IP Whitelist.  An x-header is prepended indicating the IP was whitelisted against
       SPF checks.  This is a trace header only.  This option does nothing if the domain does not
       have an SPF record.  In this case use the SPF IP Whitelist described above or
       Domain_Whitelist_PTR (below). Note the lack of spaces in the list.

       Example:

       Domain_Whitelist = pobox.com,trustedforwarder.org

       Default:

       None

PTR DOMAIN WHITELIST

       Domain_Whitelist_PTR: List of domains (and subdomains)  whose sending IPs should be
       whitelisted from SPF checks based on PTR match of the domain. Use this to list trusted
       forwarders by domain name if they do not publish SPF records.  Client IP addresses PTR
       names are tested to see if they match the listed domains.  This is useful for large
       forwarders with complex outbound infrastructures, but no SPF records and predictable host
       naming. Matching is done using the same rules as the SPF PTR mechanism as described in RFC
       4408.  List the parent domain and all subdomains will match. This option is less scalable
       than the SPF IP Whitelist.  An x-header is prepended indicating the IP was whitelisted
       against SPF checks.  This is a trace header only.  This option does nothing if the host
       does not have a PTR record record.  In this case use the SPF IP Whitelist described above.
       Note the lack of spaces in the list.

       Example:

       Domain_Whitelist_PTR = yahoo.com,yahoogroups.com

       Default:

       None

RESULTS HEADER

       The standard method for documenting SPF results in a message (for consumption by
       downstream processes) is the Received-SPF header defined in RFC 4408. This is the default
       header to use. Results can also be documented in the Authentication-Results header defined
       by RFC 5451. The default is Received-SPF (SPF), but inclusion of Authentication-Results
       (AR) headers as an alternative to Received-SPF can be specified.

       If there is a requirement to prepend both Received-SPF and Authentication- Results
       headers, then it must be done by processing the message with more than one instance of the
       policy server using different configuration files with different Header_Type settings.

       Examples:

       Header_Type = SPF or Header_Type = AR

       Default:

       SPF

Authentications Results Authentication Identifier

       Every Authentication-Results header field has an authentication identifier field
       ('Authserv_Id'). This is similar in syntax to a fully-qualified domain name. See policyd-
       spf.conf.5 and RFC 5451 paragraph 2.3 for details.  Default is None.  Authserv-Id must be
       provided if Header_Type 'AR' is used.

       The authentication identifier field provides a unique identifier that refers to the
       authenticating service within a given administrative domain. The identifier MUST be unique
       to that domain.  This identifier is intended to be machine-readable and not necessarily
       meaningful to users.

       Example:

       Authserv_Id = mx.example.com

SEE ALSO

       man 1 policyd-spf, man 5 policyd-spf.peruser, python-spf, <http://www.openspf.net>, RFC
       4408, RFC 5451

AUTHORS

       This version of pypolicyd-spf was written by Copyright © 2007-2012, Scott Kitterman
       <scott@kitterman.com>.  It is derived from Tumgreyspf, written by Sean Reifschneider,
       tummy.com, ltd <jafo@tummy.com>. Portions of the documentation were written by Meng Weng
       Wong <mengwong@pobox.com>.

       This man-page was created by Scott Kitterman <scott@kitterman.com>.

                                            2012-03-17                         policy-spf.conf(5)