I have been tackling this problem for several days and seem to have exhausted all troubleshooting, so thought I'd reach out to the community for any help.
Without introducing OpenLDAP into the mail infrastructure, Postfix and Dovecot have been operating well. For the last several days the Postfix MTA was configured with virtual LDAP settings, but emails are showing a bounced status even though Postfix can read and knows these real mail users, mail aliases and virtual domains exist. Here are the pertinent virtual settings in my Postfix main.cf.
NOTE: There are only 3 virtual LDAP configs
virtual_uid_maps = static:5000
virtual_gid_maps = static:5000
virtual_minimum_uid = 5000
virtual_mailbox_domains = ldap:/etc/postfix/ldap-virtual-domains.cf
virtual_mailbox_maps = ldap:/etc/postfix/ldap-vmailbox.cf
virtual_alias_maps = ldap:/etc/postfix/ldap-aliases.cf
virtual_mailbox_limit = 512000000
virtual_mailbox_base = /home/vmail
transport_maps = hash:/etc/postfix/transport
Here are the contents of each virtual LDAP file.
ldap-virtual-domains.cf
server_host = ldap://ldap.example.net/
search_base = ou=Domains,dc=example,dc=net
version = 3
bind = no
query_filter = (&(ObjectClass=dNSDomain)(dc=%s))
result_attribute = dc
ldap-vmailbox.cf
server_host = ldap://ldap.example.net/
search_base = ou=Mail,dc=example,dc=net
version = 3
bind = no
query_filter = (&(objectclass=inetOrgPerson)(mail=%s))
result_attribute = mail
ldap-aliases.cf
server_host = ldap://ldap.example.net/
search_base = ou=Mail,dc=example,dc=net
version = 3
bind = no
query_filter = (&(objectclass=inetLocalMailRecipient)(mailLocalAddress=%s))
result_attribute = mail
Verifying Postfix can read and process all 3 virtual LDAP files is successful
ldap-virtual-domains.cf:
postmap -q example.net ldap:/etc/postfix/ldap-virtual-domains.cf
example.net
postmap -q example.org ldap:/etc/postfix/ldap-virtual-domains.cf
example.org
postmap -q example.com ldap:/etc/postfix/ldap-virtual-domains.cf
example.com
ldap-vmailbox.cf:
postmap -q [email protected] ldap:/etc/postfix/ldap-vmailbox.cf
[email protected]
postmap -q [email protected] ldap:/etc/postfix/ldap-vmailbox.cf
[email protected]
postmap -q [email protected] ldap:/etc/postfix/ldap-vmailbox.cf
[email protected]
ldap-aliases.cf:
postmap -q [email protected] ldap:/etc/postfix/ldap-aliases.cf
[email protected]
postmap -q [email protected] ldap:/etc/postfix/ldap-aliases.cf
[email protected]
This is what I see in the mail logs:
Oct 26 16:54:17 example.net postfix/cleanup[2789]: 3D26A105CC: info: header Subject: testing virtual LDAP from [REDACTED]; [email protected] [email protected] proto=ESMTP helo=macbook-air.moon Oct 26 16:54:17 example.net postfix/cleanup[2789]: 3D26A105CC: [email protected] Oct 26 16:54:17 example.net opendkim[11877]: 3D26A105CC: [REDACTED] not internal Oct 26 16:54:17 example.net opendkim[11877]: 3D26A105CC: not authenticated Oct 26 16:54:17 example.net opendkim[11877]: 3D26A105CC: no signature data Oct 26 16:54:17 example.net postfix/qmgr[26221]: 3D26A105CC: [email protected], size=571, nrcpt=1 (queue active) Oct 26 16:54:17 example.net postfix/smtpd[2461]: disconnect from [REDACTED] ehlo=1 mail=1 rcpt=1 data=1 quit=1 commands=5 Oct 26 16:54:17 example.net postfix/pipe[2791]: 3D26A105CC: [email protected], relay=dovecot, delay=0.12, delays=0.08/0.01/0/0.02, dsn=5.1.1, status=bounced (user unknown) Oct 26 16:54:17 example.net postfix/cleanup[2789]: 55F2B1080A: [email protected] Oct 26 16:54:17 example.net postfix/qmgr[26221]: 55F2B1080A: from=, size=2460, nrcpt=1 (queue active) Oct 26 16:54:17 example.net postfix/bounce[2793]: 3D26A105CC: sender non-delivery notification: 55F2B1080A Oct 26 16:54:17 example.net postfix/qmgr[26221]: 3D26A105CC: removed Oct 26 16:54:17 example.net postfix/smtp[2794]: 55F2B1080A: [email protected], relay=none, delay=0.02, delays=0/0.01/0/0, dsn=5.4.4, status=bounced (Host or domain name not found. Name service error for name=macbook-air.moon type=A: Host not found)
Valid mail accounts existing in LDAP show this in the logs:
Oct 26 16:56:14 example.net postfix/pipe[3592]: 457871080A: [email protected], [email protected], relay=dovecot, delay=0.03, delays=0.01/0/0/0.02, dsn=5.1.1, status=bounced (user unknown)
[email protected] is a real mail address in LDAP and [email protected] is a real alias in LDAP. Postfix has no problem finding them when validating with postmap -q.
Here is the full Postfix config:
alias_database = $alias_maps alias_maps = hash:/etc/postfix/aliases append_dot_mydomain = no broken_sasl_auth_clients = yes command_directory = /usr/bin compatibility_level = 2 daemon_directory = /usr/lib/postfix/bin data_directory = /var/lib/postfix debug_peer_level = 2 debug_peer_list = 127.0.0.1 debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin ddd $daemon_directory/$process_name $process_id & sleep 5 header_checks = regexp:/etc/postfix/header_checks home_mailbox = Maildir/ html_directory = no inet_interfaces = all inet_protocols = ipv4 mail_owner = postfix mail_spool_directory = /var/spool/mail mailbox_command = /usr/lib/dovecot/deliver mailq_path = /usr/bin/mailq manpage_directory = /usr/share/man message_size_limit = 20480000 meta_directory = /etc/postfix milter_default_action = accept milter_protocol = 2 mydestination = mydomain = example.net myhostname = mail.$mydomain mynetworks = 127.0.0.0/8 10.8.0.0/24 192.168.128.0/17 [SERVER IP REDACTED] [::1]/128 [2600:3c01::]/64 [fe80::]/64 myorigin = $mydomain newaliases_path = /usr/bin/newaliases non_smtpd_milters = inet:127.0.0.1:8891 queue_directory = /var/spool/postfix readme_directory = /usr/share/doc/postfix recipient_delimiter = + sample_directory = /etc/postfix/sample sendmail_path = /usr/bin/sendmail setgid_group = postdrop shlib_directory = /usr/lib/postfix smtp_tls_mandatory_protocols = !SSLv2,!SSLv3 smtp_tls_note_starttls_offer = yes smtp_tls_protocols = !SSLv2,!SSLv3 smtp_tls_security_level = may smtpd_error_sleep_time = 1s smtpd_hard_error_limit = 20 smtpd_milters = inet:127.0.0.1:8891 smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination, check_policy_service inet:mail.example.net:12340 smtpd_sasl_auth_enable = yes smtpd_sasl_authenticated_header = yes smtpd_sasl_local_domain = smtpd_soft_error_limit = 10 smtpd_tls_CAfile = /etc/postfix/ssl/PositiveSSL.ca-bundle smtpd_tls_cert_file = /etc/postfix/ssl/STAR_example_net.crt smtpd_tls_key_file = /etc/postfix/ssl/key.pem smtpd_tls_loglevel = 1 smtpd_tls_mandatory_protocols = !SSLv2,!SSLv3 smtpd_tls_protocols = !SSLv2,!SSLv3 smtpd_tls_received_header = yes smtpd_tls_security_level = may smtpd_tls_session_cache_timeout = 3600s smtpd_use_tls = yes tls_random_source = dev:/dev/urandom transport_maps = hash:/etc/postfix/transport unknown_local_recipient_reject_code = 550 virtual_alias_maps = ldap:/etc/postfix/ldap-aliases.cf virtual_gid_maps = static:5000 virtual_mailbox_base = /home/vmail virtual_mailbox_domains = ldap:/etc/postfix/ldap-virtual-domains.cf virtual_mailbox_limit = 512000000 virtual_mailbox_maps = ldap:/etc/postfix/ldap-vmailbox.cf virtual_minimum_uid = 5000 virtual_transport = dovecot virtual_uid_maps = static:5000
Example of a valid user in LDAP with multiple aliases
It seems I am so close, but maybe another set of eyes can provide some insight towards resolving this problem. Any input is greatly appreciated.
UPDATE 1
I managed to resolve the status=bounced (user unknown) errors by changing the value of virtual_transport in main.cf from
virtual_transport = dovecot
to
virtual_transport = lmtp:unix:private/dovecot-lmtp
In master.cf I changed this line
dovecot unix - n n - - pipe flags=DRhu user=vmail:vmail argv=/usr/lib/dovecot/deliver -d ${recipient}
to this line
dovecot unix - n n - - pipe
flags=DRhu user=vmail:vmail argv=/usr/lib/dovecot/dovecot-lda -f ${sender} -d ${recipient}
I added a new user in LDAP called [email protected] and a quick postmap -q proves Postfix knows about [email protected], but then I see this error.
Oct 26 23:46:46 example.net dovecot: quota-status([email protected]): Error: User initialization failed: Namespace '': stat(/home/vmail/postmaster/.Maildir) failed: Permission denied (euid=5003() egid=5000(vmail) missing +x perm: /home/vmail, dir owned by 5000:5000 mode=0700)
Oct 26 23:46:46 example.net postfix/smtpd[25851]: NOQUEUE: reject: RCPT from[REDACTED]: 450 4.7.1 : Recipient address rejected: Invalid user settings. Refer to server log for more information.; from= to= proto=ESMTP helo=
After a bit more research I started looking at my Dovecot LDAP config, specifically dovecot-ldap.conf.ext
hosts = ldap.example.net
auth_bind = no
ldap_version = 3
base = ou=Mail,dc=example,dc=net
deref = never
scope = subtree
user_attrs = uidNumber=uid,gidNumber=gid,mailHomeDirectory=home,quotaBytes=quota_rule=*:bytes=%$
user_filter = (&(objectclass=inetOrgPerson)(mail=%u))
pass_attrs = mail=user,userPassword=password
pass_filter = (&(objectClass=posixAccount)(uid=%u))
default_pass_scheme = SSHA
I no longer see user unknown in the mail logs, but I do see failed login attempts. I don't know for sure, but think this could be from the user_attrs or any other LDAP attributes from my dovecot-ldap.conf.ext.
Oct 27 00:01:19 example.net dovecot: imap-login: Disconnected (auth failed, 1 attempts in 2 secs): user=<[email protected]>, method=PLAIN, rip=192.168.176.128, lip=192.168.176.128, TLS: Disconnected, session=<w/r1pBAj0YjAqLCA>
UPDATE 2
I created an admin account in OpenLDAP called Dovecot and gave it read access with this line
by dn="uid=dovecot,ou=System,dc=example,dc=net" read
Dovecot is now successful in reading the userPassword attribute. Here is how dovecot-ldap.conf.ext looks like with binding enabled.
hosts = ldap.example.net
auth_bind = yes
auth_bind_userdn = uid=%u,ou=Mail,dc=example,dc=net
dn = uid=dovecot,ou=System,dc=example,dc=net
dnpass = password
ldap_version = 3
base = ou=Mail,dc=example,dc=net
deref = never
scope = subtree
user_filter = (&(objectclass=inetOrgPerson)(mail=%u))
pass_filter = (&(objectclass=inetOrgPerson)(mail=%u))
default_pass_scheme = SSHA
user_attrs = uidNumber=uid,gidNumber=gid,mailHomeDirectory=,quotaBytes=quota_rule=*:bytes=%$
pass_attrs = mail=uid,userPassword=password
When trying to log into the vmail account I see Dovecot could not find the user from userdb
Oct 27 20:42:47 example.net dovecot: auth: Error: ldap(vmail,192.168.176.128,<8C7h/CEjo5DAqLCA>): user not found from userdb
Oct 27 20:42:47 example.net dovecot: imap: Error: Authenticated user not found from userdb, auth lookup id=4111597569 (client-pid=26724 client-id=1)
Oct 27 20:42:47 example.net dovecot: imap-login: Internal login failure (pid=26724 id=1) (internal failure, 1 successful auths): user=<vmail>, method=PLAIN, rip=192.168.176.128, lip=192.168.176.128, mpid=26726, secured, session=<8C7h/CEjo5DAqLCA>
If I change the user_filter attribute to the below line I can login successfully.
user_filter = (&(objectClass=posixAccount)(uid=%u))
But then messages begin bouncing again.
Oct 27 20:46:09 example.net postfix/smtp[27702]: ECA4F10848: to=<[email protected]>, relay=none, delay=0.16, delays=0.01/0.01/0.14/0, dsn=5.4.4, status=bounced (Host or domain name not found. Name service error for name=macbook-air.moon type=A: Host not found)
Oct 27 20:46:08 example.net postfix/lmtp[27698]: E0994102FA: to=<[email protected]>, relay=example.net[private/dovecot-lmtp], delay=0.06, delays=0.05/0.01/0/0, dsn=5.1.1, status=bounced (host mail.example.net[private/dovecot-lmtp] said: 550 5.1.1 <[email protected]> User doesn't exist: [email protected] (in reply to RCPT TO command))
At this point I think the problem might be the user and pass filters, but I really don't know anymore. This is the current Dovecot config from dovecot -n and the LDAP portion of Dovecot: http://ix.io/lEE
I hope this can all provide clues as to what might be missing or messed up so that user logins and sending/receiving mail are successful.
