最近，我在邮件日志中发现，我的家庭服务器发送了大量垃圾邮件。我没有运行任何网站，只运行 zpanel。我关闭了所有端口并正在监控文件mail.log。
条目如下所示：
Jul 26 13:47:37 icarus postfix/smtp[19418]: EE28911C345A: to=<[email protected]>, relay=none, delay=29791, delays=29761/0.07/31/0, dsn=4.4.1, status=deferred (connect to inbound.juliegarwood.com.netsolmail.net[206.188.198.64]:25: Connection timed out)
Jul 26 13:47:37 icarus postfix/smtp[19438]: connect to mx2.comcast.net[76.96.40.147]:25: Connection timed out
Jul 26 13:47:37 icarus postfix/smtp[19438]: connect to mx1.comcast.net[2001:558:fe14:70::22]:25: Network is unreachable
Jul 26 13:47:37 icarus postfix/smtp[19438]: connect to mx2.comcast.net[2001:558:fe2d:70::22]:25: Network is unreachable
Jul 26 13:47:37 icarus postfix/smtp[19423]: connect to extmail.bigpond.com[61.9.189.122]:25: Connection timed out
Jul 26 13:47:37 icarus postfix/smtp[19430]: connect to extmail.bigpond.com[61.9.168.122]:25: Connection timed out
Jul 26 13:47:39 icarus postfix/smtp[19420]: connect to mail.manhattan.k12.ks.us[12.167.72.199]:25: Connection timed out
Jul 26 13:47:40 icarus postfix/smtp[19420]: ECD7711C3348: to=<[email protected]>, relay=none, delay=34075, delays=34042/0.08/33/0, dsn=4.4.1, status=deferred (connect to mail.manhattan.k12.ks.us[12.167.72.199]:25: Connection timed out)
有哪些方法可以查明此问题的原因？