Postfix warning: SASL: Connect to /var/spool/postfix/private/auth failed: No such file or directory

Question

I have searched, and failed to find an answer and I am out of ideas. I just do not know enough about postfix and dovecot to parse the configs or understand what may be causing this error.

warning: SASL: Connect to /var/spool/postfix/private/auth failed: No such file or directory
fatal: no SASL authentication mechanisms

I am unable to connect with external clients (eg. Thunderbird) to postfix using SASL. I am hoping it is something obvious, but I just cannot see it.

/var/spool/postfix/private/auth exists. It is owned by postfix. Dovecot is set to use postfix as the user
Dovecot is running and listening:
unix 2 [ ACC ] STREAM LISTENING 241906 12768/dovecot /var/spool/postfix/private/auth

postconf -n output:

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
broken_sasl_auth_clients = yes
compatibility_level = 2
inet_interfaces = all
inet_protocols = all
local_recipient_maps = $virtual_mailbox_maps
local_transport = virtual
mailbox_size_limit = 0
milter_default_action = accept
milter_protocol = 2
mydestination = $myhostname, my-server.my-server.com, my-server, localhost.localdomain, localhost
myhostname = my-server
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
myorigin = /etc/mailname
non_smtpd_milters = inet:localhost:12301
readme_directory = no
recipient_delimiter = +
relay_domains = $mydestination, proxy:pgsql:/etc/postfix/pgsql/relay_domains.cf
relayhost =
smtp_sasl_auth_enable = yes
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
smtpd_milters = inet:localhost:12301
smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = yes
smtpd_sasl_path = /var/spool/postfix/private/auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_tls_cert_file = /etc/letsencrypt/live/mail.my-server.com/fullchain.pem
smtpd_tls_key_file = /etc/letsencrypt/live/mail.my-server.com/privkey.pem
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes
virtual_alias_maps = proxy:pgsql:/etc/postfix/sql/psql_virtual_alias_maps.cf, proxy:pgsql:/etc/postfix/sql/psql_virtual_alias_domain_maps.cf, proxy:pgsql:/etc/postfix/sql/psql_virtual_alias_domain_catchall_maps.cf
virtual_gid_maps = static:113
virtual_mailbox_base = /var/mail/vmail
virtual_mailbox_domains = proxy:pgsql:/etc/postfix/sql/psql_virtual_domains_maps.cf
virtual_mailbox_limit = 512000000
virtual_mailbox_maps = proxy:pgsql:/etc/postfix/sql/psql_virtual_mailbox_maps.cf, proxy:pgsql:/etc/postfix/sql/psql_virtual_alias_domain_mailbox_maps.cf
virtual_minimum_uid = 113
virtual_transport = virtual
virtual_uid_maps = static:113

dovecot -n output:

# 2.2.33.2 (d6601f4ec): /etc/dovecot/dovecot.conf
# Pigeonhole version 0.4.21 (92477967)
# OS: Linux 4.15.0-66-generic x86_64 Ubuntu 18.04.3 LTS ext4
auth_mechanisms = plain login
first_valid_uid = 113
log_path = /var/log/dovecot.log
login_greeting = My Mail Server
mail_location = maildir:/var/mail/vmail/%u/
mail_max_userip_connections = 50
mail_plugins = " zlib"
mail_privileged_group = mail
namespace inbox {
  inbox = yes
  location =
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Spam {
    special_use = \Junk
  }
  mailbox Trash {
    special_use = \Trash
  }
  prefix =
  type = private
}
passdb {
  driver = pam
}
passdb {
  args = /etc/dovecot/dovecot-sql.conf
  driver = sql
}
plugin {
  zlib_save = gz
  zlib_save_level = 6
}
protocols = imap pop3
service auth {
  group = postfix
  unix_listener /var/spool/postfix/private/auth {
    group = postfix
    mode = 0666
    user = postfix
  }
  unix_listener auth-userdb {
    group = postfix
    mode = 0666
    user = postfix
  }
  user = postfix
}
service imap-login {
  inet_listener imaps {
    port = 993
    ssl = yes
  }
}
service imap {
  executable = imap
}
ssl_cert = </etc/letsencrypt/live/mail.my-server.com/fullchain.pem
ssl_client_ca_dir = /etc/ssl/certs
ssl_key =  # hidden, use -P to show it
userdb {
  driver = passwd
}
userdb {
  args = /etc/dovecot/dovecot-sql.conf
  driver = sql
}
protocol imap {
  mail_plugins = " zlib imap_zlib"
}

blee · Answer 1 · 2020-06-20T16:12:51.957

In some distros, like Debian, postfix runs in a chroot by default. Chroot changes the apparent root directory, so postfix won't see your filesystem as you do. This is why it doesn't see /var/spool/postfix/private/auth even though the file exists and it is owned by postfix.

If you want to run postfix without chroot, edit your /etc/postfix/master.cf to set the chroot column explicitly to n for each relevant item (that's all of them, for me). Note that if you use the implicit default - you may still get chroot, apparently due to compilation defaults changed by some distro maintainers.

/etc/postfix/master.cf:

# =============================================================
# service type  private unpriv  chroot  wakeup  maxproc command
#               (yes)   (yes)   (yes)   (never) (100)
# =============================================================
smtp      inet  n       -       n       -       -       smtpd

If you prefer chrooted operation, see the documentation for preparing posfix for chroot: BASIC_CONFIGURATION_README#chroot_setup

Postfix warning: SASL: Connect to /var/spool/postfix/private/auth failed: No such file or directory

1 Answers1