25端口是邮件服务器之间沟通的，进出都必须开，否则收不到邮件，也发不了邮件。
终端用户连上来收邮件 POP3 service: port 110 over STARTTLS, or port 995 with SSL.
邮件客户端上来收邮件 IMAP service: port 143 over STARTTLS, or port 993 with SSL.
连上来发邮件 SMTP service: port 587 over STARTTLS, or port 465 with SSL.
Which network ports are open by iRedMail
| Port | Service | Software | Comment | Allow Public Access? |
|---|---|---|---|---|
| 25 | smtp | Postfix | Used for communication betweem mail servers. WARNING: This port MUST be open, otherwise you cannot receive email sent by other mail servers.（邮件服务器之间沟通使用，必须开通，否则收不到邮件） | YES (REQUIRED) |
| 587 | submission | Postfix | SMTP over TLS. Used by end users to send/submit email.(终端用户连上来发邮件) | YES (open to your end users) |
| 110 | pop3 | Dovecot | Used by end users to retrieve emails via POP3 protocol, secure connection over STARTTLS is enforced by default.（终端用户连上来收邮件） | YES (open to your end users) |
| 995 | pop3s | Dovecot | Used by end users to retrieve emails via POP3 protocol over SSL.（终端用户连上来收邮件+ssl） | YES (open to your end users) |
| 143 | imap | Dovecot | Used by end users to retrieve emails via IMAP protocol, secure connection over STARTTLS is enforced by default.（终端用IMAP协议，连上来收邮件） | YES (open to your end users) |
| 993 | imaps | Dovecot | Used by end users to retrieve emails via IMAP protocol over SSL. | YES (open to your end users) |
| 24 | lmtp | Dovecot | Used to deliver email to local mailboxes via LMTP protocol. | NO (listen on 127.0.0.1 by default) |
| 4190 | managesieve | Dovecot | Sieve service used by end users to manage mail filters. Note: in old iRedMail releases, it's port 2000 (deprecated and not even listed in /etc/services file). | NO (disabled by default and users are forced to manage mail filters with webmail) |
| 80 | http | Apache/Nginx | Web service. Redirect to https by default. | YES (open to your webmail users) |
| 443 | https | Apache/Nginx | Web service over over SSL, secure connection. | YES (open to your webmail and ActiveSync users) |
| 3306 | mysql | MySQL/MariaDB | MySQL/MariaDB database service | NO (listen on 127.0.0.1 by default) |
| 5432 | postgresql | PostgreSQL | PostgreSQL database service | NO (listen on 127.0.0.1 by default) |
| 389 | ldap | OpenLDAP (or OpenBSD ldapd) | LDAP service, STARTTLS is available for secure connection. | NO (listen on 127.0.0.1 by default) |
| 636 | ldaps | OpenLDAP (or OpenBSD ldapd) | LDAP service over SSL. Deprecated, port 389 with STARTTLS is recommended. | NO (Not enabled by default) |
| 10024 | Amavisd-new | Used to scan inbound messages, includes spam/virus scanning, DKIM verification, applying spam policy. | NO (listen on 127.0.0.1 by default) | |
| 10025 | smtp | Postfix | Used by Amavisd to inject scanned emails back to Postfix queue. | NO (listen on 127.0.0.1 by default) |
| 10026 | Amavisd-new | Used to scan outbound messages, includes spam/virus scanning, DKIM signing, applying spam policy. | NO (listen on 127.0.0.1 by default) | |
| 10027 | Amavisd-new | Used by mlmmj mailing list manager, it bypasses spam/virus/header/banned checks by default, but have DKIM signing enabled. | NO (listen on 127.0.0.1 by default) | |
| 10028 | Postfix | Used by Amavisd-new to handle email message sent by mlmmj mailing list manager. Introduced in iRedMail-0.9.9. | NO (listen on 127.0.0.1 by default) | |
| 9998 | Amavisd-new | Used to manage quarantined emails. | NO (listen on 127.0.0.1 by default) | |
| 7777 | iRedAPD | Postfix policy service for greylisting, whitelisting, blacklists, throttling, etc | NO (listen on 127.0.0.1 by default) | |
| 7778 | iRedAPD | SRS sender address rewritting. | NO (listen on 127.0.0.1 by default) | |
| 7779 | iRedAPD | SRS recipient address rewritting. | NO (listen on 127.0.0.1 by default) | |
| 7790 | http | mlmmjadmin | RESTful API server used to manage mlmmj mailing lists. Introduced in iRedMail-0.9.8. | NO (listen on 127.0.0.1 by default) |
| 7791 | http | iredadmin | iRedAdmin (standalone uwsgi instance). Introduced in iRedMail-0.9.9. | NO (listen on 127.0.0.1 by default) |
| 20000 | SOGo | SOGo groupware | NO (listen on 127.0.0.1 by default) | |
| 11211 | Memcached | A distributed, high performance memory object caching system. Currently used by only SOGo Groupware. | NO (listen on 127.0.0.1 by default) | |
| 12340 | Dovecot | Dovecot quota status. Introduced in iRedMail-1.0. | NO (listen on 127.0.0.1 by default) | |
| 24242 | Dovecot | Dovecot service status. Introduced in iRedMail-0.9.8. | NO (listen on 127.0.0.1 by default) | |
| 19999 | Netdata | Netdata monitor. Introduced in iRedMail-0.9.8. | NO (listen on 127.0.0.1 by default) |