General ideas and methods for fast email detection (3)

Setup question: is it my problem or a server problem that the POP3 Protocol cannot be used to receive emails?

This article describes how to remotely log on (Telnet) to port 110 of the mail server.

Note: after entering each row, press Enter:
Run the following command to start the telnet session:
Telnet Server IP address or domain name 110
For example, Telnet pop3.163.com 110

If a connection is established, a description of the server version from the server is displayed, which is similar to the following:
+ OK Welcome to coremail mail POP3 server (163com [20050206]) (SERVER_NAME. domain. com)

Use the following command to log on to your mailbox and start communication:
User [domain/windows_nt_account/] exchange_mailbox

For example, user ABCD

The following response is displayed:
+ OK core mail

Enter the following command:
Pass password

The following response information will be displayed, depending on the server. :
+ OK 9 message (s) [5622801 byte (s)]

Run the following command to list all emails in your mailbox:
List

The following response information will be displayed (depending on the number of emails in the mailbox, the information will change ):
+ OK
1 2895
2 1160
3 11050
4 126278
5 1503752
6 2858596
7 3352
8 54042
9 1061676

The email number is a number on the left.
Run the following command to retrieve Emails:
RETR message number
For example:
RETR 1

Emails selected by using the mail number will be displayed in the response information, similar to the following:
+ OK 1160 octets
Received: From bj.163.com (unknown [202.108.248.91])
By mx10 (coremail) with smtp id gmdgy + 9i3key8kse. 1
For <abcd@163.com>; Fri, 07 Jan 2005 16:31:43 + 0800 (CST)
X-originating-IP: [202.108.248.91]
Received: From bj66.163.com (unknown [202.108.248.66])
By bj.163.com (postfix) with esmtp id cea05180a2
For <abcd@163.com>; Fri, 7 Jan 2005 16:32:19 + 0800 (CST)
Message-ID: <9175756.1105086779838.JavaMail.root@bj66.163.com>
From: "Netease tribe" <admin@bulo.163.com>
To: abcd@163.com
Subject: =? GBK? B? U7btrct6vnpi68340teyv8lkoam =? =
Mime-type: 1.0
Content-Type: text/plain
Content-transfer-encoding: 8bit
Charset: gb2312
Date: Fri, 7 Jan 2005 16:32:19 + 0800 (CST)
The following is the omitted essay of the email.

Exit
Quit
+ OK core mail
This process helps diagnose and solve the communication problem between the POP3 client and the mailbox located on the Exchange Server.