1

Topic: Email not signed with DKIM

======== Required information ====
- iRedMail version: v0.2.2
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====

I'm trying to get DKIM setup on my email server. I only have one domain. Outgoing emails aren't being signed with DKIM keys. I'm not sure how it will impact things, but the server is mail.example.com but the email addresses are all @example.com.

Sample email:

Delivered-To: user@gmail.com
Received: by 10.217.108.73 with SMTP id cc51csp273332web;
        Wed, 16 Apr 2014 14:07:21 -0700 (PDT)
X-Received: by 10.182.158.135 with SMTP id wu7mr8367632obb.28.1397682440307;
        Wed, 16 Apr 2014 14:07:20 -0700 (PDT)
Return-Path: <username@example.com>
Received: from mail.example.com (mail.example.com. [xxx.xxx.xxx.xxx])
        by mx.google.com with ESMTP id we10si19594010obc.111.2014.04.16.14.07.19
        for <user@gmail.com>;
        Wed, 16 Apr 2014 14:07:20 -0700 (PDT)
Received-SPF: pass (google.com: domain of username@example.com designates xxx.xxx.xxx.xxx as permitted sender) client-ip=xxx.xxx.xxx.xxx;
Authentication-Results: mx.google.com;
       spf=pass (google.com: domain of username@example.com designates xxx.xxx.xxx.xxx as permitted sender) smtp.mail=username@example.com
Received: from localhost (localhost.localdomain [127.0.0.1])
    by mail.example.com (Postfix) with ESMTP id B77183C6622
    for <user@gmail.com>; Wed, 16 Apr 2014 16:06:19 -0500 (CDT)
X-Virus-Scanned: Debian amavisd-new at example.com
Received: from mail.example.com ([127.0.0.1])
    by localhost (mail.example.com [127.0.0.1]) (amavisd-new, port 10024)
    with ESMTP id BEZ3cCDLjakD for <user@gmail.com>;
    Wed, 16 Apr 2014 16:06:11 -0500 (CDT)
Received: from mail.example.com (localhost.localdomain [127.0.0.1])
    by mail.example.com (Postfix) with ESMTPA id DDE0E3C58B5
    for <user@gmail.com>; Wed, 16 Apr 2014 16:06:10 -0500 (CDT)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8;
format=flowed
Content-Transfer-Encoding: 7bit
Date: Wed, 16 Apr 2014 16:06:10 -0500
From: My Name <username@example.com>
To: Name Gmail <user@gmail.com>
Subject: DKIM Test
Organization: Weldon Parts Inc.
Message-ID: <5f5ab4bd94c6f0fe532460426ad89a1e@example.com>
X-Sender: username@example.com
User-Agent: RoundCube WebMail

This is just a test.

postconf -n

alias_database = hash:/etc/postfix/aliases
alias_maps = hash:/etc/postfix/aliases
allow_min_user = no
allow_percent_hack = no
append_dot_mydomain = no
biff = no
bounce_queue_lifetime = 4h
broken_sasl_auth_clients = yes
config_directory = /etc/postfix
content_filter = smtp-amavis:[127.0.0.1]:10024
delay_warning_time = 0h
detect_8bit_encoding_header = no
disable_mime_input_processing = yes
disable_mime_output_conversion = yes
disable_vrfy_command = yes
dovecot_destination_recipient_limit = 1
enable_original_recipient = no
home_mailbox = Maildir/
inet_interfaces = all
inet_protocols = ipv4
mailbox_command = /usr/lib/dovecot/deliver
mailbox_size_limit = 0
maximal_backoff_time = 4000s
maximal_queue_lifetime = 4h
message_size_limit = 15728640
minimal_backoff_time = 300s
mydestination = $myhostname, localhost, localhost.localdomain, localhost.$myhostname localhost.$mydomain www.$mydomain mail.example.com
mydomain = example.com
myhostname = mail.example.com
mynetworks = 127.0.0.0/8 172.17.2.0/24 192.168.0.0/16
mynetworks_style = subnet
myorigin = example.com
proxy_read_maps = $canonical_maps $lmtp_generic_maps $local_recipient_maps $mydestination $mynetworks $recipient_bcc_maps $recipient_canonical_maps $relay_domains $relay_recipient_maps $relocated_maps $sender_bcc_maps $sender_canonical_maps $smtp_generic_maps $smtpd_sender_login_maps $transport_maps $virtual_alias_domains $virtual_alias_maps $virtual_mailbox_domains $virtual_mailbox_maps $smtpd_sender_restrictions
queue_run_delay = 300s
readme_directory = no
recipient_bcc_maps = proxy:mysql:/etc/postfix/mysql/recipient_bcc_maps_user.cf, proxy:mysql:/etc/postfix/mysql/recipient_bcc_maps_domain.cf
recipient_delimiter = +
relay_domains = $mydestination, proxy:mysql:/etc/postfix/mysql/relay_domains.cf
relayhost =
sender_bcc_maps = proxy:mysql:/etc/postfix/mysql/sender_bcc_maps_user.cf, proxy:mysql:/etc/postfix/mysql/sender_bcc_maps_domain.cf
smtp-amavis_destination_recipient_limit = 1
smtp_data_init_timeout = 240s
smtp_data_xfer_timeout = 600s
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
smtpd_data_restrictions = reject_unauth_pipelining
smtpd_delay_reject = yes
smtpd_end_of_data_restrictions =
smtpd_helo_required = yes
smtpd_helo_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_non_fqdn_helo_hostname, reject_invalid_helo_hostname, permit
smtpd_recipient_restrictions = reject_unknown_sender_domain, reject_unlisted_recipient, reject_unauth_pipelining, reject_non_fqdn_recipient, reject_unknown_recipient_domain, reject_rbl_client sbl-xbl.spamhaus.org, reject_rbl_client bl.spamcop.net, reject_rbl_client cbl.abuseat.org, permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination, check_sender_access hash:/etc/postfix/sender_access, permit
smtpd_reject_unlisted_recipient = yes
smtpd_reject_unlisted_sender = yes
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = no
smtpd_sasl_local_domain = example.local
smtpd_sasl_path = ./dovecot-auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_sender_login_maps = proxy:mysql:/etc/postfix/mysql/sender_login_maps.cf
smtpd_sender_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_non_fqdn_sender, reject_unknown_sender_domain, reject_sender_login_mismatch, permit
smtpd_tls_CAfile = /etc/ssl/certs/iRedMail_CA.pem
smtpd_tls_cert_file = /etc/ssl/certs/iRedMail_CA.pem
smtpd_tls_key_file = /etc/ssl/private/iRedMail.key
smtpd_tls_loglevel = 0
smtpd_tls_security_level = may
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes
swap_bangpath = no
tls_random_source = dev:/dev/urandom
transport_maps = proxy:mysql:/etc/postfix/mysql/transport_maps_user.cf, proxy:mysql:/etc/postfix/mysql/transport_maps_domain.cf
virtual_alias_domains =
virtual_alias_maps = proxy:mysql:/etc/postfix/mysql/virtual_alias_maps.cf, proxy:mysql:/etc/postfix/mysql/domain_alias_maps.cf, proxy:mysql:/etc/postfix/mysql/catchall_maps.cf, proxy:mysql:/etc/postfix/mysql/domain_alias_catchall_maps.cf
virtual_gid_maps = static:2000
virtual_mailbox_base = /var/vmail
virtual_mailbox_domains = proxy:mysql:/etc/postfix/mysql/virtual_mailbox_domains.cf
virtual_mailbox_maps = proxy:mysql:/etc/postfix/mysql/virtual_mailbox_maps.cf
virtual_minimum_uid = 2000
virtual_transport = dovecot
virtual_uid_maps = static:2000

master.cf

#
# Postfix master process configuration file.  For details on the format
# of the file, see the master(5) manual page (command: "man 5 master").
#
# Do not forget to execute "postfix reload" after editing this file.
#
# ==========================================================================
# service type  private unpriv  chroot  wakeup  maxproc command + args
#               (yes)   (yes)   (yes)   (never) (100)
# ==========================================================================
smtp      inet  n       -       -       -       -       smtpd
#smtp      inet  n       -       -       -       1       postscreen
#smtpd     pass  -       -       -       -       -       smtpd
#dnsblog   unix  -       -       -       -       0       dnsblog
#tlsproxy  unix  -       -       -       -       0       tlsproxy
#submission inet n       -       -       -       -       smtpd
#  -o syslog_name=postfix/submission
#  -o smtpd_tls_security_level=encrypt
#  -o smtpd_sasl_auth_enable=yes
#  -o smtpd_client_restrictions=permit_sasl_authenticated,reject
#  -o milter_macro_daemon_name=ORIGINATING
smtps     inet  n       -       -       -       -       smtpd
#  -o syslog_name=postfix/smtps
#  -o smtpd_tls_wrappermode=yes
#  -o smtpd_sasl_auth_enable=yes
#  -o smtpd_client_restrictions=permit_sasl_authenticated,reject
#  -o milter_macro_daemon_name=ORIGINATING
#628       inet  n       -       -       -       -       qmqpd
pickup    fifo  n       -       -       60      1       pickup
cleanup   unix  n       -       -       -       0       cleanup
qmgr      fifo  n       -       n       300     1       qmgr
#qmgr     fifo  n       -       n       300     1       oqmgr
tlsmgr    unix  -       -       -       1000?   1       tlsmgr
rewrite   unix  -       -       -       -       -       trivial-rewrite
bounce    unix  -       -       -       -       0       bounce
defer     unix  -       -       -       -       0       bounce
trace     unix  -       -       -       -       0       bounce
verify    unix  -       -       -       -       1       verify
flush     unix  n       -       -       1000?   0       flush
proxymap  unix  -       -       n       -       -       proxymap
proxywrite unix -       -       n       -       1       proxymap
smtp      unix  -       -       -       -       -       smtp
relay     unix  -       -       -       -       -       smtp
#       -o smtp_helo_timeout=5 -o smtp_connect_timeout=5
showq     unix  n       -       -       -       -       showq
error     unix  -       -       -       -       -       error
retry     unix  -       -       -       -       -       error
discard   unix  -       -       -       -       -       discard
local     unix  -       n       n       -       -       local
virtual   unix  -       n       n       -       -       virtual
lmtp      unix  -       -       -       -       -       lmtp
anvil     unix  -       -       -       -       1       anvil
scache    unix  -       -       -       -       1       scache
#
# ====================================================================
# Interfaces to non-Postfix software. Be sure to examine the manual
# pages of the non-Postfix software to find out what options it wants.
#
# Many of the following services use the Postfix pipe(8) delivery
# agent.  See the pipe(8) man page for information about ${recipient}
# and other message envelope options.
# ====================================================================
#
# maildrop. See the Postfix MAILDROP_README file for details.
# Also specify in main.cf: maildrop_destination_recipient_limit=1
#
maildrop  unix  -       n       n       -       -       pipe
  flags=DRhu user=vmail argv=/usr/bin/maildrop -d ${recipient}
#
# ====================================================================
#
# Recent Cyrus versions can use the existing "lmtp" master.cf entry.
#
# Specify in cyrus.conf:
#   lmtp    cmd="lmtpd -a" listen="localhost:lmtp" proto=tcp4
#
# Specify in main.cf one or more of the following:
#  mailbox_transport = lmtp:inet:localhost
#  virtual_transport = lmtp:inet:localhost
#
# ====================================================================
#
# Cyrus 2.1.5 (Amos Gouaux)
# Also specify in main.cf: cyrus_destination_recipient_limit=1
#
#cyrus     unix  -       n       n       -       -       pipe
#  user=cyrus argv=/cyrus/bin/deliver -e -r ${sender} -m ${extension} ${user}
#
# ====================================================================
# Old example of delivery via Cyrus.
#
#old-cyrus unix  -       n       n       -       -       pipe
#  flags=R user=cyrus argv=/cyrus/bin/deliver -e -m ${extension} ${user}
#
# ====================================================================
#
# See the Postfix UUCP_README file for configuration details.
#
uucp      unix  -       n       n       -       -       pipe
  flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)
#
# Other external delivery methods.
#
ifmail    unix  -       n       n       -       -       pipe
  flags=F user=ftn argv=/usr/lib/ifmail/ifmail -r $nexthop ($recipient)
bsmtp     unix  -       n       n       -       -       pipe
  flags=Fq. user=bsmtp argv=/usr/lib/bsmtp/bsmtp -t$nexthop -f$sender $recipient
scalemail-backend unix    -    n    n    -    2    pipe
  flags=R user=scalemail argv=/usr/lib/scalemail/bin/scalemail-store ${nexthop} ${user} ${extension}
mailman   unix  -       n       n       -       -       pipe
  flags=FR user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py
  ${nexthop} ${user}

submission inet n       -       n       -       -       smtpd
  -o smtpd_tls_security_level=encrypt
  -o smtpd_sasl_auth_enable=yes
  -o smtpd_client_restrictions=permit_mynetworks,permit_sasl_authenticated,reject
#  -o content_filter=smtp-amavis:[127.0.0.1]:10026

# Use dovecot deliver program as LDA.
dovecot unix    -       n       n       -       -      pipe
    flags=DRhu user=vmail:vmail argv=/usr/lib/dovecot/deliver -f ${sender} -d ${user}@${domain} -m ${extension}

smtp-amavis unix -  -   -   -   2  smtp
    -o smtp_data_done_timeout=1200
    -o smtp_send_xforward_command=yes
    -o disable_dns_lookups=yes
    -o max_use=20

127.0.0.1:10025 inet n  -   -   -   -  smtpd
    -o content_filter=
    -o local_recipient_maps=
    -o relay_recipient_maps=
    -o smtpd_restriction_classes=
    -o smtpd_delay_reject=no
    -o smtpd_tls_security_level=none
    -o smtpd_client_restrictions=permit_mynetworks,reject
    -o smtpd_helo_restrictions=
    -o smtpd_sender_restrictions=
    -o smtpd_recipient_restrictions=permit_mynetworks,reject
    -o smtpd_end_of_data_restrictions=
    -o mynetworks_style=host
    -o mynetworks=127.0.0.0/8
    -o strict_rfc821_envelopes=yes
    -o smtpd_error_sleep_time=0
    -o smtpd_soft_error_limit=1001
    -o smtpd_hard_error_limit=1000
    -o smtpd_client_connection_count_limit=0
    -o smtpd_client_connection_rate_limit=0
    -o receive_override_options=no_header_body_checks,no_unknown_recipient_checks,no_address_mappings

amavisd-new showkeys

dkim._domainkey.mail.example.com.    3600 TXT (
  "v=DKIM1; p="
  "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDDszux+vg8Ud1ynEv0GcymyIb1"
  "lyEHOL5Io3EWv7DVxHqmYTLAEhJcV9QtZxVKavK1umysa/lKtau7gFWzH/bnpS8g"
  "p1OjsteMPQiK3ztTarGezJbcoKoJ3+azUpiaxmHt8dFWbTQuccyBeW2+6amzIuVs"
  "Wm4/27JI6664lkiH3wIDAQAB")

amavisd-new testkeys

TESTING#1: dkim._domainkey.mail.example.com => pass

A dig gets it's info from our internal DNS server as indicated by the server IP. I also noticed that there is no answer section. When I check from external websites, like http://www.protodave.com/tools/dkim-key-checker/ then it correctly checks our public DNS records and returns a success.

dig -t txt dkim._mail.example.com

; <<>> DiG 9.8.4-rpz2+rl005.12-P1 <<>> -t txt dkim._mail.example.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 26752
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;dkim._mail.example.com.    IN    TXT

;; AUTHORITY SECTION:
example.com.    3600    IN    SOA    okc-dc-02.example.local. hostmaster.example.local. 9 900 600 86400 3600

;; Query time: 0 msec
;; SERVER: 172.xxx.xxx.xxx#53(172.xxx.xxx.xxx)
;; WHEN: Wed Apr 16 16:19:49 2014
;; MSG SIZE  rcvd: 133

And the following is uncommented in /etc/amavis/conf.d/50-user

$enable_dkim_verification = 1;  # enable DKIM signatures verification
$enable_dkim_signing = 1;    # load DKIM signing code, keys defined by dkim_key

I am not sure what else to check. Any help at all would be greatly appreciated. Thank you.

----

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2

Re: Email not signed with DKIM

bmoore wrote:

From: My Name <username@example.com>

You should sign DKIM for domain 'example.com', not 'mail.example.com'. So, please:

1: Generate DKIM key for domain 'example.com'.
2: Update Amavisd to enable DKIM signing for domain 'example.com'.
3: Add DNS record for DKIM for domain 'example.com'.

3

Re: Email not signed with DKIM

ZhangHuangbin wrote:
bmoore wrote:

From: My Name <username@example.com>

You should sign DKIM for domain 'example.com', not 'mail.example.com'. So, please:

1: Generate DKIM key for domain 'example.com'.
2: Update Amavisd to enable DKIM signing for domain 'example.com'.
3: Add DNS record for DKIM for domain 'example.com'.

Awesome! That took care of it. For some reason after making the update to amavisd for the new key I couldn't access the server using the public IP. I fixed it by adding a forward lookup zone and an A record on my DNS server. I'm not sure why that affected it, but I wanted to share that in case anyone comes accross this and has a similar issue.

Thank you very much for the help. smile