I just configured opendkim and postfix and it is supossed to be signing my emails but it doesn't.

I used /usr/sbin/opendkim-testkey to test the keys and it seems to be ok with them but the mails I send to check-auth@verifier.port25.com keep saying:

Summary of Results
SPF check:          pass
DomainKeys check:   pass
DKIM check:         neutral
Sender-ID check:    pass
SpamAssassin check: ham

Any ideas? I got postfix configuration file like this:

# OpenDKIM
milter_default_action = accept
milter_protocol = 6
smtpd_milters = , inet:, inet:
non_smtpd_milters = $smtpd_milters

I did check my log files tons of times and nothing seems to be wrong. I am using Centos 6.

Also this is my opendkim.conf

## See opendkim.conf(5) or /usr/share/doc/opendkim/opendkim.conf.sample for more

## BEFORE running OpenDKIM you must:

## - make your MTA (Postfix, Sendmail, etc.) aware of OpenDKIM
## - generate keys for your domain (if signing)
## - edit your DNS records to publish your public keys (if signing)

## See /usr/share/doc/opendkim/INSTALL for detailed instructions.


# Specifies the path to the process ID file.
PidFile /var/run/opendkim/opendkim.pid

# Selects operating modes. Valid modes are s (sign) and v (verify). Default is v.
# Must be changed to s (sign only) or sv (sign and verify) in order to sign outgoing
# messages.
Mode    v

# Log activity to the system log.
Syslog  yes

# Log additional entries indicating successful signing or verification of messages.
SyslogSuccess   yes

# If logging is enabled, include detailed logging about why or why not a message was
# signed or verified. This causes an increase in the amount of log data generated
# for each message, so set this to No (or comment it out) if it gets too noisy.
LogWhy  yes

# Attempt to become the specified user before starting operations.
UserID  opendkim:opendkim

# Create a socket through which your MTA can communicate.
Socket  inet:8891@localhost

# Required to use local socket with MTAs that access the socket as a non-
# privileged user (e.g. Postfix)
Umask   002

# This specifies a text file in which to store DKIM transaction statistics.
# OpenDKIM must be manually compiled with --enable-stats to enable this feature.
#Statistics     /var/spool/opendkim/stats.dat


# Selects the canonicalization method(s) to be used when signing messages.
Canonicalization        relaxed/relaxed

# Domain(s) whose mail should be signed by this filter. Mail from other domains will
# be verified rather than being signed. Uncomment and use your domain name.
# This parameter is not required if a SigningTable is in use.
#Domain example.com

# Defines the name of the selector to be used when signing messages.
Selector        mail

# Specifies the minimum number of key bits for acceptable keys and signatures.
MinimumKeyBits 1024

# Gives the location of a private key to be used for signing ALL messages. This
# directive is ignored if KeyTable is enabled.
KeyFile /etc/opendkim/keys/default.private

# Gives the location of a file mapping key names to signing keys. In simple terms,
# this tells OpenDKIM where to find your keys. If present, overrides any KeyFile
# directive in the configuration file. Requires SigningTable be enabled.
KeyTable        /etc/opendkim/KeyTable

# 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. In simple terms, this tells
# OpenDKIM how to use your keys. Requires KeyTable be enabled.
SigningTable    refile:/etc/opendkim/SigningTable

# Identifies a set of "external" hosts that may send mail through the server as one
# of the signing domains without credentials as such.
ExternalIgnoreList      refile:/etc/opendkim/TrustedHosts

# Identifies a set "internal" hosts whose mail should be signed rather than verified.
InternalHosts   refile:/etc/opendkim/TrustedHosts

This is my log by the way:

May 29 07:34:07 s18378428 opendkim[5801]: OpenDKIM Filter v2.10.1 starting (args: -x /etc/opendkim.conf -P /var/run/opendkim/opendkim.pid)
May 29 07:35:02 s18378428 opendkim[5801]: 5562C18C60060: verifier.port25.com [] not internal
May 29 07:35:02 s18378428 opendkim[5801]: 5562C18C60060: not authenticated
May 29 07:35:02 s18378428 opendkim[5801]: 5562C18C60060: DKIM verification successful

Thanks for your time.

P.D.: Just in case, I got the DNS records right and the propper keys for my domain.


In your opendkim.conf file

Mode    v

sets the operating mode to verify only, so your outgoing messages will never be signed.
This is explained in the comment right above the relevant line:

Selects operating modes. Valid modes are s (sign) and v (verify). Default is v.
Must be changed to s (sign only) or sv (sign and verify) in order to sign outgoing

I suspect your log entries come from incoming mail (i.e. from verifier.port25.com) being verified rather than outgoing mail being signed.

A "good" log entry for signing an outgoing message would be

opendkim[23616]: 085726031E: DKIM-Signature header added (s=mail1, d=example.tld)
  • I did figured out this the last night. But thank you anyways. I will accept your answer. – Asier Paz May 30 '15 at 14:59

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