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- iRedMail 版本号：0.9.5
- 使用哪个数据库存储用户帐号（OpenLDAP，MySQL，PostgreSQL）：mysql
- 使用的 Linux/BSD 发行版名称及版本号：raspbian 8.0
- 与您的问题相关的日志信息：
Mar 28 01:49:49 server postfix/qmgr[24208]: 155EC103D37: from=<wchan@xxxxxx.com>, size=8603773, nrcpt=1 (queue active)
Mar 28 01:49:49 server postfix/smtpd[25183]: disconnect from mlwcfa03.xxxxxx.com[174.47.187.51]
Mar 28 01:49:53 server postfix/pipe[25597]: 155EC103D37: to=<it@server.mailxxxxxx.com>, relay=dovecot, delay=4155, delays=4151/0.04/0/3.6, dsn=2.0.0, status=sent (delivered via dovecot service)
Mar 28 01:49:53 server postfix/qmgr[24208]: 155EC103D37: removed
Mar 28 01:51:28 server postfix/postscreen[25606]: CONNECT from [174.47.187.51]:57303 to [58.240.247.43]:25
Mar 28 01:51:28 server postfix/postscreen[25606]: PASS OLD [174.47.187.51]:57303
Mar 28 01:51:28 server postfix/smtpd[25183]: connect from mlwcfa03.xxxxxx.com[174.47.187.51]
Mar 28 01:51:33 server postfix/smtpd[25183]: Anonymous TLS connection established from mlwcfa03.xxxxxx.com[174.47.187.51]: TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)
Mar 28 01:51:36 server postfix/smtpd[25183]: 7CE53103D37: client=mlwcfa03.xxxxxx.com[174.47.187.51]
Mar 28 01:54:55 server postfix/anvil[24219]: statistics: max connection rate 1/60s for (smtpd:200.87.52.4) at Mar 28 01:47:18
Mar 28 01:54:55 server postfix/anvil[24219]: statistics: max connection count 5 for (smtpd:174.47.187.51) at Mar 28 01:51:28
Mar 28 01:54:55 server postfix/anvil[24219]: statistics: max cache size 2 at Mar 28 01:47:18
Mar 28 01:57:07 server postfix/postscreen[25610]: CONNECT from [24.43.42.42]:56328 to [58.240.247.43]:25
Mar 28 01:57:07 server postfix/postscreen[25610]: PASS OLD [24.43.42.42]:56328
Mar 28 01:57:07 server postfix/smtpd[25611]: connect from rrcs-24-43-42-42.west.biz.rr.com[24.43.42.42]
Mar 28 01:57:20 server postfix/smtpd[25611]: improper command pipelining after AUTH from rrcs-24-43-42-42.west.biz.rr.com[24.43.42.42]: QUIT\r\n
Mar 28 01:57:20 server postfix/smtpd[25611]: disconnect from rrcs-24-43-42-42.west.biz.rr.com[24.43.42.42]
Mar 28 02:00:44 server postfix/qmgr[24208]: BE581103D22: from=<wchan@xxxxxx.com>, size=8603773, nrcpt=1 (queue active)
Mar 28 02:00:44 server postfix/smtpd[25210]: disconnect from mlwcfa03.xxxxxx.com[174.47.187.51]
Mar 28 02:00:45 server postfix/pipe[25624]: BE581103D22: to=<it@server.mailxxxxxx.com>, relay=dovecot, delay=4493, delays=4491/0.04/0/1.3, dsn=2.0.0, status=sent (delivered via dovecot service)
Mar 28 02:00:45 server postfix/qmgr[24208]: BE581103D22: removed
Mar 28 02:03:22 server postfix/postscreen[25688]: CONNECT from [96.57.19.234]:58991 to [58.240.247.43]:25
Mar 28 02:03:22 server postfix/postscreen[25688]: PASS OLD [96.57.19.234]:58991
Mar 28 02:03:27 server postfix/smtpd[25689]: warning: hostname ool-603913ea.static.optonline.net does not resolve to address 96.57.19.234
Mar 28 02:03:27 server postfix/smtpd[25689]: connect from unknown[96.57.19.234]
Mar 28 02:03:37 server postfix/smtpd[25689]: disconnect from unknown[96.57.19.234]
Mar 28 02:04:55 server postfix/anvil[24219]: statistics: max connection rate 1/60s for (smtpd:24.43.42.42) at Mar 28 01:57:07
Mar 28 02:04:55 server postfix/anvil[24219]: statistics: max connection count 1 for (smtpd:24.43.42.42) at Mar 28 01:57:07
Mar 28 02:04:55 server postfix/anvil[24219]: statistics: max cache size 2 at Mar 28 01:57:07
Mar 28 02:07:14 server postfix/qmgr[24208]: 51AB1103C5F: from=<wchan@xxxxxx.com>, size=8603773, nrcpt=1 (queue active)
Mar 28 02:07:14 server postfix/smtpd[25286]: disconnect from mlwcfa03.xxxxxx.com[174.47.187.51]
Mar 28 02:07:16 server postfix/pipe[25693]: 51AB1103C5F: to=<it@server.mailxxxxxx.com>, relay=dovecot, delay=3827, delays=3825/0.03/0/1.9, dsn=2.0.0, status=sent (delivered via dovecot service)
Mar 28 02:07:16 server postfix/qmgr[24208]: 51AB1103C5F: removed
====
张工你好，因为之前公司的邮件服务器一直会重复收到对方的附件较大的邮件，重复数量几十封，但是双方服务器一直都正常使用。
我就搭个临时的iremail测试服务器，让对方抄送过来，发现问题是否重现与网络运营商有关系，电信环境下正常，移动和联通环境下就还是有重复问题。
只要（relay=dovecot, delay=3827）中delay数值大，就会重复收取邮件。
请问，除了更换运营商和让对方查原因，还有什么办法能避免重复收取邮件。