邮局常用端口有哪些？ pop，smtp，25，110，587、465、2525

常见邮件协议

发邮件：SMTP（加密版本SMTPS）

收邮件：IMAP（加密版本IMAPS）、POP3（加密版本POP3S）

邮件协议端口号

SMTP：   TCP 25

IMAP：    TCP 143

POP3：   TCP 110

SMTPS： TCP 465

IMAPS：  TCP 993

POP3S： TCP 995

SMTP端口25 (SMTP Port 25)

Port 25 is the first official port of the SMTP. Port 25 is dedicated for the SMTP in 1982. SMTP Port 25 uses the TCP as a transmission protocol. Also, Port 25 is the most known and popular port for SMTP. As an old, popular, and well-known port Port 25 is abused widely and some ISP, Network, and Cloud providers automatically or by default blocks the TCP 25 SMTP port in order to prevent abuses and security attacks.

端口25是SMTP的第一个正式端口。 1982年，端口25专用于SMTP。SMTP端口25使用TCP作为传输协议。 另外，端口25是SMTP最著名和最受欢迎的端口。 端口25作为一个古老，流行且知名的端口，被广泛滥用，并且某些ISP，网络和云提供程序自动或默认情况下阻止TCP 25 SMTP端口，以防止滥用和安全攻击。

SMTP端口587 (SMTP Port 587)

SMTP Port 587 is the default port for email submission and used by a lot of parties. If you don’t know the default port of the remote email server the best choice to start check for submission is used the SMTP port 587. Port 587 is provided as a TCP port. Also, port 597 provides a secure email submission by using TLS encryption.

SMTP端口587是电子邮件提交的默认端口，并被许多各方使用。 如果您不知道远程电子邮件服务器的默认端口，则使用SMTP端口587作为开始检查提交的最佳选择。端口587作为TCP端口提供。 同样，端口597通过使用TLS加密提供了安全的电子邮件提交。

SMTP端口465 (SMTP Port 465)

SMTP port was the first secure and encrypted email submission port which is using SMTP over SSL methodology. After some time with the emerge of the Port 587 SMTP port 465 is deprecated officially and provided for use of other protocols. But today many ISP and cloud hosting providers support and provide port 465 for SMTP submission.

SMTP端口是第一个使用SMTP over SSL方法的安全加密电子邮件提交端口。 在端口587出现一段时间后，SMTP端口465正式被弃用，并提供使用其他协议。 但是今天，许多ISP和云托管提供商都支持并提供465端口用于SMTP提交。

SMTP端口2525 (SMTP Port 2525)

SMTP port 2525 is a tricky port that is created by typing 25 twice as port 25 is the first port number of the SMTP. Port 2525 is not assigned officially for the SMTP usage because it is not recognized by authorities IETF or IANA. But the similarity of the numbers made port 2525 popular and most of the ISPs, cloud service providers and email servers support and allow access of port 2525 SMTP service. Especially Port 2525 will be a good alternative can if port 587 is blocked.

SMTP端口2525是一个棘手的端口，通过键入25两次来创建，因为端口25是SMTP的第一个端口号。 未正式为SMTP使用分配端口2525，因为IETF或IANA当局无法识别该端口。 但是数字的相似性使2525端口变得流行，并且大多数ISP，云服务提供商和电子邮件服务器都支持并允许访问2525端口SMTP服务。 如果端口587被阻塞，则特别是2525端口将是一个很好的选择。