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 <
http://www.openspf.org>.
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=Please see http://www.openspf.org/why.html?
sender=user%40example.com&ip=1.2.3.4&receiver=localhost
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>.