我的服务器 (ubuntu postfix /dovecot) 发送了一批垃圾邮件，在我的日志中我看到 gmail (帐户已链接) 已连接并发送了邮件？我应该怎么做才能防止这种情况发生？
Jul 31 12:27:5 mail postfix/smtpd[21087]: F1C88240FE1: client=mail-io0-f174.google.com[209.85.223.174], sasl_method=PLAIN, [email protected]
Jul 31 12:27:36 mail postfix/cleanup[21091]: F1C88240FE1: message-id=<CABzTzmM_R2bTqMLziiHjaezHKXJVWXYqnuhNZaPWC5BXH6kv5w@mail.gmail.com>
Jul 31 12:27:36 mail postfix/qmgr[17904]: F1C88240FE1: from=<[email protected]>, size=37573, nrcpt=1 (queue active)
July 31 12:27:36 mail postfix/smtpd[21087]: disconnect from mail-io0-f174.google.com[209.85.223.174]
Jul 31 12:27:36 mail postfix/smtp[21092]: F1C88240FE1: to=>> <[email protected]>, relay=mail.astoilov96.com[195.24.40.66]:25, delay=0.85, delays=0.3/0.01/0.25/0.3, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as ABA9D23C0098)
Jul 31 12:27:36 mail postfix/qmgr[17904]: F1C88240FE1: removedJul 31