我得到了这些 Postfix 信息的组合，我想知道我是否应该了解某事/某人。
30.4.2018, 10:08:33 info statistics: max cache size 1 at Apr 30 10:05:13
30.4.2018, 10:08:33 info statistics: max connection count 1 for (smtpd:87.243.7.183) at Apr 30 10:05:13
30.4.2018, 10:08:33 info statistics: max connection rate 1/60s for (smtpd:87.243.7.183) at Apr 30 10:05:13
30.4.2018, 10:05:13 info disconnect from unknown[87.243.7.183] helo=1 auth=0/1 quit=1 commands=2/3
30.4.2018, 10:05:13 info connect from unknown[87.243.7.183]
30.4.2018, 10:05:13 warning warning: hostname 183.7.243.87.static.primetelecom.ro does not resolve to address 87.243.7.183: Name or service not known
30.4.2018, 10:05:12 info PASS OLD [87.243.7.183]:64492
30.4.2018, 10:05:09 info addr 87.243.7.183 listed by domain zen.spamhaus.org as 127.0.0.4
30.4.2018, 10:05:09 info Look up 87.243.7.183 on whitelist, result 200 DUNNO
30.4.2018, 10:05:09 info CONNECT from [87.243.7.183]:64492 to [172.22.1.6]:25
30.4.2018, 09:56:57 info DISCONNECT [182.176.115.31]:54308
30.4.2018, 09:56:57 info DNSBL rank 14 for [182.176.115.31]:54308
30.4.2018, 09:56:55 info addr 182.176.115.31 listed by domain zen.spamhaus.org as 127.0.0.4
30.4.2018, 09:56:55 info addr 182.176.115.31 listed by domain zen.spamhaus.org as 127.0.0.11
30.4.2018, 09:56:54 info Look up 182.176.115.31 on whitelist, result 200 DUNNO
30.4.2018, 09:56:54 info CONNECT from [182.176.115.31]:54308 to [172.22.1.6]:25
30.4.2018, 09:51:40 info statistics: max cache size 1 at Apr 30 09:48:20
30.4.2018, 09:51:40 info statistics: max connection count 1 for (smtpd:87.243.7.183) at Apr 30 09:48:20
30.4.2018, 09:51:40 info statistics: max connection rate 1/60s for (smtpd:87.243.7.183) at Apr 30 09:48:20
30.4.2018, 09:50:00 info DISCONNECT [185.234.216.221]:59101
30.4.2018, 09:50:00 info DNSBL rank 9 for [185.234.216.221]:59101
30.4.2018, 09:50:00 info addr 185.234.216.221 listed by domain b.barracudacentral.org as 127.0.0.2
30.4.2018, 09:49:57 info addr 185.234.216.221 listed by domain zen.spamhaus.org as 127.0.0.4
30.4.2018, 09:49:57 info addr 185.234.216.221 listed by domain zen.spamhaus.org as 127.0.0.2
30.4.2018, 09:49:57 info PREGREET 11 after 0.03 from [185.234.216.221]:59101: EHLO User\r\n
30.4.2018, 09:49:56 info Look up 185.234.216.221 on whitelist, result 200 DUNNO
30.4.2018, 09:49:56 info CONNECT from [185.234.216.221]:59101 to [172.22.1.6]:25
30.4.2018, 09:48:20 info disconnect from unknown[87.243.7.183] helo=1 auth=0/1 quit=1 commands=2/3
30.4.2018, 09:48:20 info connect from unknown[87.243.7.183]
30.4.2018, 09:48:20 warning warning: hostname 183.7.243.87.static.primetelecom.ro does not resolve to address 87.243.7.183: Name or service not known
有些部分像Look up 182.176.115.31 on whitelist, result 200 DUNNO或PASS OLD [87.243.7.183]:64492我真的不太明白。PASS OLD 或 PASS NEW 是什么意思？我在 Google 上搜索并阅读了一些有关垃圾邮件预防的内容，但对我来说这看起来像是垃圾邮件，那么为什么 Postfix 会阻止 IP 呢？
答案1
看一下postfix的“postscreen”功能：
http://www.postfix.org/POSTSCREEN_README.html
对不同的 RBL 服务进行 RBL 检查，以检查发送邮件服务器是否是垃圾邮件发送者。
日志条目DNSBL rank显示所有测试的排名值。如果该值超过postscreen_dnsbl_threshold由 配置的排名值3，则服务器将拒绝该邮件，并要求发件人稍后再试。大多数垃圾邮件发送者不会这样做，因为他们只会尝试发送尽可能多的邮件，而不会尝试重新发送。
Postscreen 将记住来自特定发送服务器和接收邮件地址的连接尝试。
如果postscreen_dnsbl_threshold未达到，稍后将再次尝试让邮件通过（使用 进行记录PASS NEW）。
如果服务器在几分钟后重新发送邮件，postscreen 将允许它（使用 记录它PASS OLD），