Why email sending and receiving are abnormal

A. Why can I send or receive emails?

1. Port 25 of your IP address is blocked in the IDC, or port 25 is restricted in your firewall.
You can test it like this:
Enter
Telnet smtp.163.com 25
The prompt message in English is displayed normally.
If the IP address is blocked by the data center, contact the data center for processing.

2. the DNS of your email software is not set, for example, the DNS server in Imail is not set. You can go to --- IMail-IMail administrator to open the IMail management interface and enter the dns ip address in localhost -- serviecs --- SMTP ---- "Domina name address, multiple IP addresses can be separated by spaces. The dns ip address must be the same as the dns ip address set in TCP/IP in the NIC attribute.

3. Send a mail with an incorrect email address. If the admin user using winwebmail cannot send a mail, bind the domain name in the user area and send a mail again.

4. It may be caused by anti-virus software, such as McAfee and rising. You can disable anti-virus software, restart the email software, and try again.

B. the email software has been installed, but the email cannot receive the email.

Cause 1: The MX record of the domain name is not resolved
The mydns function of xinnet is described as follows:
For example, the domain name test.com
First, you need to resolve the record of mail.test.com to your server IP address in the record.
Then, in MX resolution, parse test.com and write mail.test.com as the host name. Note !!!
It is used to parse the MX record of test.com, not the MX record of mail.test.com, which is the most common error.

Cause 2: Firewall or port conflict
The mailbox requires port 25,110. check whether this port is opened and whether it conflicts with the SMTP port in IIS. SMTP in IIS can use port 26.

cause 3: The IMail is not successfully cracked, or the IMail SMTP service is not started. If you are sure that the IMail SMTP service has been started, you can run
netstat-An
in DOS. Normally, port 25 is listening. if the SMTP service is started without port 25, it is likely that IMail has not been cracked. In this case, you can only reinstall the system to restore IMail.