我在带有 FirewallD 的 CentOs 7 上运行服务器，并在该服务器上运行带有 Poste.io 邮件服务器的 Docker。（SQLite、Dovecot、NGiNX、Haraka、RSPAMD、ClamAV、Roundcube、Z-Push）
所以我的问题是我无法接收电子邮件，但我可以毫无问题地发送电子邮件。我已在 FirewallD 中手动打开所有端口 （FirewallD 列表截图：https://i.stack.imgur.com/Ih70k.png） 但仍然只能使用端口 25 出站，而不能使用端口 25 入站。如 poste.io Adminpanel 中的 Serverstatus 所示 （poste.io 管理面板中的服务器状态截图：https://i.stack.imgur.com/CzyPh.png）
（我不知道为什么它不能通过 IPv4 连接到自身……）
DNS 似乎与 MX 和 A 记录配合使用。它找到了服务器，但它主动拒绝接收。我通过https://ismyemailworking.com/AdvancedTest/
测试日志：
01/16/2020 09:53:23 - [IsMyEmailWorking.com email test started]
01/16/2020 09:53:24 - [Querying DNS for responsible mail servers for 'l***.at']
01/16/2020 09:53:24 - [Starting DNS Session]
01/16/2020 09:53:24 - [RFC 5321 5. The lookup first attempts to locate an MX record associated with the name. If a CNAME record is found, the resulting name is processed as if it were the initial name. If no MX records are found, but an A RR is found, the A RR is treated as if it was associated with an implicit MX RR, with a preference of 0, pointing to that host.]
01/16/2020 09:53:24 - [Trying to get MX Records for 'l***.at']
01/16/2020 09:53:25 - [Found MX Record 'mail.l***.at' Preference '10']
01/16/2020 09:53:25 - [Found 1 MX Records]
01/16/2020 09:53:25 - [Searching Found MX Records for Host Records]
01/16/2020 09:53:25 - [MX Record 'mail.l***.at' Did not include any Host records. Queueing 'mail.l***.at' for further resolution.]
01/16/2020 09:53:25 - [Performing Additional Queries for Host records for MX Records that are queued for further resolution]
01/16/2020 09:53:25 - [Found an A Host Record for 'mail.l***.at' of '37.252.***.***']
01/16/2020 09:53:25 - [Completed Additional Queries for Host records]
01/16/2020 09:53:25 - [DNS Session completed]
01/16/2020 09:53:25 - [Found 1 responsible mail servers for 'l***.at']
01/16/2020 09:53:29 - [Selected target email server to test 'mail.l***.at/37.252.***.***']
01/16/2020 09:53:30 - [Starting SMTP Session]
01/16/2020 09:53:30 - [Attempting to connect to 'mail.l***.at/37.252.***.***']
01/16/2020 09:53:30 - [Connecting to 37.252.***.***:25.]
01/16/2020 09:53:32 - [Exception: No connection could be made because the target machine actively refused it 37.252.***.***:25]
答案1
我不知道操作系统上的 Postfix 从启动时就开始运行......它捕获了来自端口 25 的所有传入消息。
现在我禁用了 Postfix 并可以接收电子邮件。