我使用下面的教程在 Digital Ocean 服务器上设置 postfix 和 dovecot。但是当 postfix/smtp 尝试将电子邮件发送到 gmail 或 yahoo 等远程主机时，我收到了“连接超时”的消息。
https://www.digitalocean.com/community/articles/how-to-set-up-a-postfix-e-mail-server-with-dovecot
接收新消息 /var/log/mail.log
Feb 2 22:33:38 localhost dovecot：auth-worker：调试：从目录加载模块：/usr/lib/dovecot/modules/auth
Feb 2 22:33:38 localhost dovecot: auth-worker: Debug: pam(app,189.63.49.XXX): 查找服务=dovecot
Feb 2 22:33:38 localhost dovecot: auth-worker: Debug: pam(app,189.63.49.XXX): #1/1 style=1 msg=Password:
Feb 2 22:33:38 localhost dovecot: auth: Debug: client out: OK#0111#011user=app
Feb 2 22:33:40 localhost postfix/submission/smtpd[1045]: E9AA724264: client=unknown[189.63.49.XXX], sasl_method=PLAIN, sasl_username=app
2 月 2 日 22:33:43 本地主机后缀/清理 [1052]：E9AA724264：消息 ID=
Feb 2 22:33:43 localhost postfix/qmgr[32661]: E9AA724264: from=, size=485, nrcpt=1 (queue active)
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我需要监控 Linux 服务器上的 Apache、Mysql、Mongrel、Rails、Exim 以及 Load、网络、I/O 等服务...我知道 Cacti、Nagios...还有其他更好的监控工具吗？
在检查 Exim 的日志消息时，我发现以下消息的许多条目“发件人验证失败”“拒绝 RCPT”...我不是 exim 专家...恐怕 Exim 没有将 100% 电子邮件发送给收件人，因为我们的电子邮件营销应用程序的打开率较低。
有人可以帮助理解这个日志消息吗？是我的服务器说“这里没有这样的用户”还是远程服务器？174.111.111.11代表我的服务器IP。谢谢
进出口日志
2010-10-02 14:00:19 SMTP connection from myserverdomain.com.br () [174.111.111.11]:54514 I=[174.111.111.11]:25 closed by QUIT
2010-10-02 14:00:19 SMTP connection from [174.111.111.11]:54515 I=[174.111.111.11]:25 (TCP/IP connection count = 2)
2010-10-02 14:00:19 H=myserverdomain.com.br () [174.111.111.11]:54515 I=[174.111.111.11]:25 Warning: Sender rate 672.4 / 1h
2010-10-02 14:00:19 H=myserverdomain.com.br () [174.111.111.11]:54515 I=[174.111.111.11]:25 sender verify fail for <fernandagaglianone=oi.com.br--2723--bounce@e-mydomain.com.br>: No Such User Here
2010-10-02 14:00:19 H=myserverdomain.com.br () [174.111.111.11]:54515 I=[174.111.111.11]:25 F=<fernandagaglianone=oi.com.br--2723--bounce@e-mydomain.com.br> rejected RCPT <fernandagaglianone@oi.com.br>: Sender verify failed
2010-10-02 14:00:19 SMTP connection …