我猜这是两个典型的问题，至少第一个是。我正在尝试在 CentOS 7 上配置 postfix dovecot。
首先，端口 25 是开放的，但它不接受任何外部连接。
端口 25 处的内部连接正常。我执行了以下操作：
[root@myhost ~]# telnet localhost smtp
Trying ::1...
Connected to localhost.
Escape character is '^]'.
220 xxxx.com ESMTP Postfix (CentOS)
helo xxxx
250 xxxx.com
mail from:<[email protected]>
250 2.1.0 Ok
rcpt to:<[email protected]>
250 2.1.5 Ok
data
354 End data with <CR><LF>.<CR><LF>
from:[email protected]
to:[email protected]
subject:Testing email
test test
.
250 2.0.0 Ok: queued as CBE5F6039
quit
221 2.0.0 Bye
Connection closed by foreign host.
然后我检查了我的 Dovecot 服务器/var/mail/vhosts/xxxx.com/user1：
./new
./new/1693231789.M572537P2155.xxxx,S=495,W=510
因此，对于典型的 SMTP（端口 25），我的配置完全正确。但问题是，当我尝试发送或远程登录时，它没有任何反应。日志文件是空的。所以我试了一下，tcpdump -i any port smtp它告诉我端口 25 根本没有打开。
所以我猜这只是典型的 Linux 错误，某些东西阻止了端口 25 监听。如果有人知道这是什么，请告诉我。
第二，465端口不工作。
似乎 Postfix 要么由于某些配置错误而没有监听它，要么被我的 Linux 内部的某些东西阻止了端口 465。（或者 SSL 可能不正确）
我在自己的电脑上尝试tcpdump -i any port smtps过。telnet mail.xxxx.com smtps
服务器显示端口 465 确实收到了数据包。但是，postfix 没有任何响应。
于是我查看了 上的邮件日志/var/log/maillog，它显示 postfix 根本没有识别和响应我的 telnet 连接。以下是日志：
Aug 28 13:42:37 xxxx postfix/postfix-script[1692]: starting the Postfix mail system
Aug 28 13:42:37 xxxx postfix/master[1694]: daemon started -- version 2.10.1, configuration /etc/postfix
什么都没有。所以我猜想 Linux 上的某些设置或防火墙阻止了服务“实际”监听 smtp 端口。有人知道吗？
然后我尝试从端口 465 上的本地主机进行 telnet，但似乎端口 465 上的内部连接也不起作用。
在我的服务器上，我执行了以下操作：
[root@myhost ~]# telnet localhost smtps
Trying ::1...
Connected to localhost.
Escape character is '^]'.
helo xxxx
Connection closed by foreign host.
'helo'之后就关闭了。然后我再次访问/var/log/maillog，显示如下：
Aug 28 13:45:57 xxxx postfix/smtps/smtpd[1974]: connect from unknown[::1]
Aug 28 13:46:01 xxxx postfix/smtps/smtpd[1974]: SSL_accept error from unknown[::1]: -1
Aug 28 13:46:01 xxxx postfix/smtps/smtpd[1974]: warning: TLS library problem: 1974:error:140760FC:SSL routines:SSL23_GET_CLIENT_HELLO:unknown protocol:s23_srvr.c:640:
Aug 28 13:46:01 xxxx postfix/smtps/smtpd[1974]: lost connection after CONNECT from unknown[::1]
Aug 28 13:46:01 xxxx postfix/smtps/smtpd[1974]: disconnect from unknown[::1]
这是我的配置文件。
sudo postconf-n
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin ddd $daemon_directory/$process_name $process_id & sleep 5
html_directory = no
inet_interfaces = localhost
inet_protocols = all
mail_owner = postfix
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
mydestination = localhost, localhost.$mydomain
mydomain = xxxx.com
myhostname = xxxx.com
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
recipient_delimiter = +
sample_directory = /usr/share/doc/postfix-2.10.1/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtp_tls_security_level = may
smtpd_banner = $myhostname ESMTP $mail_name (CentOS)
smtpd_sasl_security_options = noanonymous, noplaintext
smtpd_sasl_tls_security_options = noanonymous
smtpd_tls_auth_only = yes
smtpd_tls_cert_file = /etc/letsencrypt/live/xxxx.com/fullchain.pem
smtpd_tls_key_file = /etc/letsencrypt/live/xxxx.com/privkey.pem
smtpd_tls_security_level = may
smtpd_use_tls = yes
unknown_local_recipient_reject_code = 550
virtual_mailbox_domains = mysql:/etc/postfix/mysql-virtual-mailbox-domains.cf
virtual_mailbox_maps = mysql:/etc/postfix/mysql-virtual-mailbox-maps.cf
virtual_transport = lmtp:unix:private/dovecot-lmtp
部分/etc/postfix/main.cf
mail_owner = postfix
myhostname = xxxx.com
mydomain = xxxx.com
# TLS parameters
smtpd_tls_cert_file=/etc/letsencrypt/live/xxxx,com/fullchain.pem
smtpd_tls_key_file=/etc/letsencrypt/live/xxxx.com/privkey.pem
smtpd_use_tls=yes
smtpd_tls_auth_only = yes
smtp_tls_security_level = may
smtpd_tls_security_level = may
smtpd_sasl_security_options = noanonymous, noplaintext
smtpd_sasl_tls_security_options = noanonymous
inet_interfaces = all
#inet_interfaces = $myhostname
#inet_interfaces = $myhostname, localhost
inet_interfaces = localhost
# Enable IPv4, and IPv6 if supported
inet_protocols = all
mydestination = localhost, localhost.$mydomain
virtual_mailbox_domains = mysql:/etc/postfix/mysql-virtual-mailbox-domains.cf
virtual_mailbox_maps = mysql:/etc/postfix/mysql-virtual-mailbox-maps.cf
recipient_delimiter = +
virtual_transport = lmtp:unix:private/dovecot-lmtp
部分/etc/postfix/master.cf
smtp inet n - n - 1 postscreen
#smtpd pass - - n - - smtpd
#dnsblog unix - - n - 0 dnsblog
#tlsproxy unix - - n - 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_sasl_type=dovecot
-o smtpd_sasl_path=private/auth
-o smtpd_reject_unlisted_recipient=no
#-o smtpd_client_restrictions=permit_sasl_authenticated,reject
-o milter_macro_daemon_name=ORIGINATING
465 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_sasl_type=dovecot
-o smtpd_sasl_path=private/auth
#-o smtpd_client_restrictions=permit_sasl_authenticated,reject
-o milter_macro_daemon_name=ORIGINATING
答案1
感谢上面@HBruijn的评论，我解决了这个问题。问题是我配置了两个inet_interfaces。
值得一提的是，在当前的 postfix 配置文件中， 似乎是inet_interfaces = localhost一个默认值，并且被取消注释。但是被注释了。因此，在取消注释 时inet_interfaces = all，您需要注释。inet_interfaces = localhostinet_interfaces = all
该文件为：/etc/postfix/master.cf。