myhostname = mail.xxx.com
mydomain = xxx.com
myorigin = $mydomain
inet_interfaces = all
inet_protocols = ipv4
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain = $mydomain
smtpd_sasl_security_options = noanonymous
smtpd_use_tls = yes
smtp_tls_security_level = may
smtpd_tls_cert_file = /xx.pem
smtpd_tls_key_file = /xx.pem
smtpd_tls_loglevel = 1
smtpd_tls_received_header = yes
master.cf的配置：
submission inet n - n - - smtpd
-o syslog_name=postfix/submission
-o smtpd_tls_security_level=encrypt
-o smtpd_sasl_auth_enable=yes
-o smtpd_tls_auth_only=yes
在vps上给gmail发邮件，log显示：
Jul 24 13:07:13 xxx postfix/smtp[1369]: connect to gmail-smtp-in.l.google.com[64.233.188.27]:25: O
peration timed out
Jul 24 13:07:43 xxx postfix/smtp[1369]: connect t
o alt1.gmail-smtp-in.l.google.com[64.233.179.27]:
25: Operation timed out
Jul 24 13:08:13 xxx postfix/smtp[1369]: connect t
o alt2.gmail-smtp-in.l.google.com[74.125.126.27]:
25: Operation timed out
...
Jul 24 13:09:13 xxx postfix/smtp[1369]: xxxxxx: to=<xxxx@gmail.com>, relay=none, delay=1
51, delays=0.03/0.03/150/0, dsn=4.4.1, status=def
erred (connect to alt4.gmail-smtp-in.l.google.com
[173.194.66.26]:25: Operation timed out)
邮件发不出去！用外部邮箱给这台vps发邮件也发不进来！
已开放了系统的587端口，25端口被屏蔽，无法使用。
已添加A记录mail.xxx.com和MX记录、txt记录。
我是新手，第一次建邮件服务器，配置都是抄网上的，请问是哪里出错了？
