spfd(1): simple forking daemon to provide SPF ...

NAME

spfd - simple forking daemon to provide SPF query services

SYNOPSIS

spfd --port port [--set-user uid|username] [--set-group gid|groupname]

spfd --socket filename [--socket-user uid|username] [--socket-group gid|groupname] [--socket-perms octal-perms] [--set-user uid|username] [--set-group gid|groupname]

spfd --help

DESCRIPTION

spfd is a simple forking Sender Policy Framework (SPF) query proxy server. spfd receives and answers SPF query requests on a TCP/IP or UNIX domain socket.

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 --help form prints usage information for spfd.

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 key=value, where the following keys are required:

ip: The sender IP address.
sender: The envelope sender address (from the SMTP "MAIL FROM" command).
helo: The envelope sender hostname (from the SMTP "HELO" command).

RESPONSE

spfd responds to query requests with similar series of lines of the form key=value. The most important response keys are:

result

The result of the SPF query:

pass: The specified IP address is an authorized mailer for the sender domain/address.
fail: The specified IP address is not an authorized mailer for the sender domain/address.
softfail: The specified IP address is not an authorized mailer for the sender domain/address, however the domain is still in the process of transitioning to SPF.
neutral: The sender domain makes no assertion about the status of the IP address.
unknown: The sender domain has a syntax error in its SPF record.
error: A temporary DNS error occurred while resolving the sender policy. Try again later.
none: There is no SPF record for the sender domain.

smtp_comment

The text that should be included in the receiver's SMTP response.

header_comment

The text that should be included as a comment in the message's "Received-SPF:" header.

spf_record

The SPF record of the envelope sender domain.

For the description of other response keys see Mail::SPF::Query.

For more information on SPF see <http://www.openspf.org>.

EXAMPLE

A running spfd could be tested using the "netcat" utility like this:

    $ echo -e "ip=11.22.33.44\nsender=user@pobox.com\nhelo=spammer.example.net\n" | nc localhost 5970
    result=neutral
    smtp_comment=Please see http://spf.pobox.com/why.html?sender=user%40pobox.com&ip=11.22.33.44&receiver=localhost
    header_comment=localhost: 11.22.33.44 is neither permitted nor denied by domain of user@pobox.com
    guess=neutral
    smtp_guess=
    header_guess=
    guess_tf=neutral
    smtp_tf=
    header_tf=
    spf_record=v=spf1 ?all

AUTHORS

This version of spfd was written by Meng Weng Wong <mengwong+spf@pobox.com>. Improved argument parsing was added by Julian Mehnle <julian@mehnle.net>.

This man-page was written by Julian Mehnle <julian@mehnle.net>.