Provided by: spf-tools-perl_2.9.0-5_all 
NAME
spfd - (Mail::SPF) - Simple forking daemon to provide SPF query services
VERSION
2.000
SYNOPSIS
spfd --port|-p port [--set-user|-u uid|username] [--set-group|-g gid|groupname] [OPTIONS]
spfd --socket|-s filename [--socket-user uid|username] [--socket-group gid|groupname]
[--socket-perms octal-perms] [--set-user|-u uid|username] [--set-group|-g gid|groupname]
[OPTIONS]
spfd --version|-V
spfd --help
DESCRIPTION
spfd is a simple forking Sender Policy Framework (SPF) query server. spfd receives and
answers SPF requests on a TCP/IP or UNIX domain socket. For more information on SPF see
<https://tools.ietf.org/html/rfc7208>.
The --port form listens on a TCP/IP socket on the specified port. The default port is
5970.
The --socket form listens on a UNIX domain socket that is created with the specified
filename. The socket can be assigned specific user and group ownership with the
--socket-user and --socket-group options, and specific filesystem permissions with the
--socket-perms option.
Generally, spfd can be instructed with the --set-user and --set-group options to drop root
privileges and change to another user and group before it starts listening for requests.
The --version form prints version information of spfd. The --help form prints usage
information for spfd.
OPTIONS
spfd takes any of the following OPTIONS:
--default-explanation string
--def-exp string
Use the specified string as the default explanation if the authority domain does not
specify an explanation string of its own.
--hostname hostname
Use hostname as the host name of the local system instead of auto-detecting it.
--debug
Print out debug information about spfd's operation, incoming requests, and the
responses sent.
REQUEST
A request consists of a series of lines delimited by \x0A (LF) characters (or whatever
your system considers a newline). Each line must be of the form option=value, where the
following options are supported:
versions
A comma-separated list of SPF version numbers of SPF records that may be used. 1
means that "v=spf1" records should be used. 2 means that "spf2.0" records should be
used. Defaults to 1,2, i.e., uses any SPF records that are available. Records of a
higher version are preferred.
scope
The authorization scope of the identity that should be checked. Defaults to 'mfrom'.
The following scope values are supported: 'helo', 'mfrom', 'pra'. See "new" in
Mail::SPF::Request for more information.
identity
Required. The sender identity whose authorization should be checked. This is a
domain name for the "helo" scope, and an e-mail address for the "mfrom" and "pra"
scopes.
ip_address
Required for checks with the "helo", "mfrom", and "pra" scopes. The IP address of the
host claiming the identity that is being checked. Can be either an IPv4 or an IPv6
address. An IPv4-mapped IPv6 address (e.g. '::ffff:192.168.0.1') is treated as an
IPv4 address.
helo_identity
The "HELO" SMTP transaction parameter in the case that the main identity is of a scope
other than "helo". This identity is then used merely for the expansion of "%{h}"
macros during the policy evaluation of the main identity. If unspecified with a scope
other than "helo", defaults to "unknown". If the main identity is of the "helo"
scope, this option is unused.
RESPONSE
spfd responds to SPF requests with similar series of lines of the form key=value. The
most important response keys are:
result
The result code of the SPF check:
pass The specified IP address is an authorized SMTP sender for the identity.
fail The specified IP address is not an authorized SMTP sender for the
identity.
softfail The specified IP address is not an authorized SMTP sender for the
identity, however the authority domain is still testing out its SPF
policy.
neutral The identity's authority domain makes no assertion about the status of the
IP address.
permerror A permanent error occurred while evaluating the authority domain's policy
(e.g., a syntax error in the SPF record). Manual intervention is required
from the authority domain.
temperror A temporary error occurred while evaluating the authority domain's policy
(e.g., a DNS error). Try again later.
none There is no applicable SPF policy for the identity domain.
local_explanation
A locally generated explanation of the SPF result.
authority_explanation
The authority domain's explanation for the SPF result. Be aware that the authority
domain may be a malicious party and thus the authority explanation should not be
trusted blindly. See RFC 4408, 10.5, for a detailed discussion of this issue.
received_spf_header
An appropriate "Received-SPF" header field for the SPF result.
spf_record
The authority domain's SPF record that was used for the policy evaluation.
EXAMPLE
A running spfd could be tested using the "netcat" utility like this (line breaks added for
clarity):
$ echo -e "identity=user@example.com\nip_address=1.2.3.4\n" \
| nc localhost 5970
result=fail
local_explanation=example.com: Sender is not authorized by default to use
'user@example.com' in 'mfrom' identity (mechanism '-all' matched)
authority_explanation=Rejected by SPF record
received_spf_header=Received-SPF: fail (example.com: Sender is not
authorized by default to use 'user@example.com' in 'mfrom' identity
(mechanism '-all' matched)) receiver=localhost; identity=mfrom;
envelope-from="user@example.com"; client-ip=1.2.3.4
spf_record=v=spf1 mx -all
COMPATIBILITY
spfd has undergone the following interface changes compared to earlier versions:
2.000
· A new preferred request style has been introduced. Instead of the old "sender"
request option, which is specific to the "MAIL FROM" SMTP identity, a generic
"identity" option should now be specified. In addition, a "scope" option may be
given to specify the identity's scope, otherwise a scope of "mfrom" is assumed.
The old "ip" and "helo" options have been replaced by the "ip_address" and
"helo_identity" options, respectively.
This is how legacy requests with the "mfrom" scope would translate to the new
preferred request style:
Legacy request style | New request style
----------------------------+---------------------------------------
| scope=mfrom
sender=<mfrom-identity> | identity=<mfrom-identity>
ip=<ip-address> | ip_address=<ip-address>
helo=<helo-identity> | helo_identity=<helo-identity>
A new response style featuring new response values has also been introduced:
Legacy response style | New response style
----------------------------+---------------------------------------
result=<result-code> | result=<result-code>
header_comment=<local-exp> | local_explanation=<local-exp>
smtp_comment=<local-exp | authority_explanation=<authority-exp>
or authority-exp> |
spf_record=<spf-record> | spf_record=<spf-record>
| received_spf_header=<header>
The legacy request style is deprecated but still supported for backwards
compatibility. The legacy response values are still returned for backwards
compatibility in addition to the new response values, but may be removed in the
future. Adjust your code to use the new request and response styles.
· The former "unknown" and "error" result codes have been renamed to "permerror" and
"temperror", respectively, in order to comply with RFC 4408 terminology.
· SPF checks with an empty identity are no longer supported. In the case of an
empty "MAIL FROM" SMTP transaction parameter, perform a check with the "helo"
scope directly.
SEE ALSO
Mail::SPF, spfquery(1)
<http://tools.ietf.org/html/rfc4408>
AUTHORS
This version of spfd is a complete rewrite by Julian Mehnle <julian@mehnle.net>, based on
an earlier version written by Meng Weng Wong <mengwong+spf@pobox.com>.