使用 Haraka 搭建的邮件服务器不能远程连接，有没有人遇到？

使用 Haraka(https://github.com/baudehlo/Haraka) 搭建了邮件服务器，使用 127.0.0.1 连接可以正常发信，但是使用公网 IP 连接的时候，无法发信。有没有人遇到过？

smtp.ini 监听了两个 IP 和对应的端口，服务端也能收到请求的信息，但是不会返回认证方式。
auth_flat_file.ini 使用的 CRAW-MD5 认证方式。

一段日志

[PROTOCOL] [F5B2C046-4485-4B31-832D-947D67E66291] [core] S: 250-open Hello li596-113.members.linode.com [106.186.23.113], Haraka is at your service.
[PROTOCOL] [F5B2C046-4485-4B31-832D-947D67E66291] [core] S: 250-PIPELINING
[PROTOCOL] [F5B2C046-4485-4B31-832D-947D67E66291] [core] S: 250-8BITMIME
[PROTOCOL] [F5B2C046-4485-4B31-832D-947D67E66291] [core] S: 250 SIZE 500000
[PROTOCOL] [F5B2C046-4485-4B31-832D-947D67E66291] [core] C: AUTH PLAIN AG5vcmVwbHlAbWFC53dWxpYW5m91cC5jbgAwTjJZNE9USXhZeg== state=1
[DEBUG] [F5B2C046-4485-4B31-832D-947D67E66291] [core] running unrecognized_command hooks
[DEBUG] [F5B2C046-4485-4B31-832D-947D67E66291] [core] running unrecognized_command hook in auth/flat_file plugin
[DEBUG] [F5B2C046-4485-4B31-832D-947D67E66291] [core] hook=unrecognized_command plugin=auth/flat_file function=hook_unrecognized_command params="AUTH" retval=CONT msg=""
[PROTOCOL] [F5B2C046-4485-4B31-832D-947D67E66291] [core] S: 500 Unrecognized command
[WARN] [F5B2C046-4485-4B31-832D-947D67E66291] [core] client li596-11.members.linode.com [106.186.23.113] half closed connection
[DEBUG] [F5B2C046-4485-4B31-832D-947D67E66291] [core] running disconnect hooks