我已按照本指南设置电子邮件服务器：https://www.linode.com/docs/email/postfix/email-with-postfix-dovecot-and-mysql
我可以正常发送和接收，我还安装了 roundcube，它允许我发送和接收电子邮件，因为它设置为使用邮件功能来发送电子邮件。
但是，如果我使用电子邮件客户端 Geary，它允许我接收电子邮件并检查我的收件箱，但通过 SMTP 发送完全不起作用，基本上连接超时并且 mail.log 中没有显示任何正在发生的日志。
我觉得从上面的帖子中，我已经明白了 Postfix 没有cyrus-sasl支持设置的原因是什么？但那篇帖子针对的操作系统与我使用的操作系统不同。
我使用的是 Debian 8，我的问题是我需要 cyrus-sasl 吗？我运行postconf -a后它只显示cyrus“dovecot否” cyrus-sasl，我甚至不确定如何安装它。
我发现无法连接到 587 上的 Postfix但读完之后发现似乎没什么效果？为什么没有可靠的解决方案呢？
同时，当我重新启动 postfix 时，我收到以下警告：
postfix[15180]: /usr/sbin/postconf: warning: /etc/postfix/master.cf: undefined parameter: mua_sender_restrictions
Jun 9 00:58:31 postfix[15180]: /usr/sbin/postconf: warning: /etc/postfix/master.cf: undefined parameter: mua_client_restrictions
Jun 9 00:58:31 postfix[15180]: /usr/sbin/postconf: warning: /etc/postfix/master.cf: undefined parameter: mua_helo_restrictions
Jun 9 00:58:31 postfix[15180]: /usr/sbin/postconf: warning: /etc/postfix/master.cf: undefined parameter: mua_sender_restrictions
Jun 9 00:58:31 postfix[15180]: /usr/sbin/postconf: warning: /etc/postfix/master.cf: undefined parameter: mua_client_restrictions
Jun 9 00:58:31 postfix[15180]: /usr/sbin/postconf: warning: /etc/postfix/master.cf: undefined parameter: mua_helo_restrictions
更新：
主配置文件
# See /usr/share/postfix/main.cf.dist for a commented, more complete version
# Debian specific: Specifying a file name will cause the first
# line of that file to be used as the name. The Debian default
# is /etc/mailname.
myorigin = /etc/mailname
smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
biff = no
# appending .domain is the MUA's job.
append_dot_mydomain = no
# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h
readme_directory = no
#Enable TLS/ SASL/ SSL
smtpd_tls_cert_file=/etc/letsencrypt/live/mail.[my.domain].com/fullchain.pem
smtpd_tls_key_file=/etc/letsencrypt/live/mail.[my.domain].com/privkey.pem
smtpd_use_tls=yes
smtpd_tls_auth_only = yes
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain = $myhostname
smtpd_tls_security_level = may
smtpd_tls_loglevel = 1
broken_sasl_auth_clients = yes
#Enabling SMTP for authenticated users, and handing off authentication to Dovecot
smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
smtpd_sasl_auth_enable=yes
# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.
smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, check_relay_domains
smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = Thunderbird-1
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
#mydestination = Thunderbird-1, localhost.localdomain, localhost
mydestination = localhost
relayhost =
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
#Handing off local delivery to Dovecot's LMTP, and telling it where to store mail
virtual_transport = lmtp:unix:private/dovecot-lmtp
#Virtual domains, users, and aliases
virtual_mailbox_domains = mysql:/etc/postfix/mysql-virtual-mailbox-domains.cf
virtual_mailbox_maps = mysql:/etc/postfix/mysql-virtual-mailbox-maps.cf
virtual_alias_maps = mysql:/etc/postfix/mysql-virtual-alias-maps.cf,
mysql:/etc/postfix/mysql-virtual-email2email.cf
主配置文件
#
# Postfix master process configuration file. For details on the format
# of the file, see the master(5) manual page (command: "man 5 master" or
# on-line: http://www.postfix.org/master.5.html).
#
# 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_reject_unlisted_recipient=no
-o smtpd_client_restrictions=permit_sasl_authenticated,reject
# -o smtpd_client_restrictions=$mua_client_restrictions
# -o smtpd_helo_restrictions=$mua_helo_restrictions
# -o smtpd_sender_restrictions=$mua_sender_restrictions
-o smtpd_recipient_restrictions=
-o smtpd_relay_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_reject_unlisted_recipient=no
-o smtpd_client_restrictions=$mua_client_restrictions
-o smtpd_helo_restrictions=$mua_helo_restrictions
-o smtpd_sender_restrictions=$mua_sender_restrictions
-o smtpd_recipient_restrictions=
-o smtpd_relay_restrictions=permit_sasl_authenticated,reject
-o milter_macro_daemon_name=ORIGINATING
#628 inet n - - - - qmqpd
pickup unix n - - 60 1 pickup
cleanup unix n - - - 0 cleanup
qmgr unix n - n 300 1 qmgr
#qmgr unix 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}