MDaemon mail server:-err connection refused

Today, my friend called to say that their server is not stable. Due to line problems, a friend moved the email server to the telecom data center two days ago. After the transfer, I tested it. It was still quite normal. As soon as we went to work on Monday, we couldn't do it. The Foxmail client of all employees in the company reported this error and did nothing, after a period of time, it will be good again. The following error is reported on the Foxmail client.

This error message indicates that the server rejects the client. At first, I thought it was a problem with anti-virus software and firewall. I remotely checked the server's anti-virus software and firewall. Everything went fine. I created a new account to access the Internet normally, and everything went fine when I sent and received emails from the Foxmail client. When I remotely access the client and port 25 of the Telnet server, the following error is returned:

A friend's email server is stored in a telecom data center. The company exports a fixed public IP address and uses the Pat address to switch to access the mail server on the public network. View server logs and shield the logs that record their company's public IP addresses. During the test on Friday evening, only one person was visiting and went to work on Monday. Almost all users in the company were using the service. Any of the following conditions would trigger dynamic blocking, the IP address is blocked for 10 minutes, so it will be good occasionally, but will soon be blocked.

In this way, the problem is very simple. Security --- Security Settings --- shielding --- dynamic shielding. Click the [whitelist] button to add the fixed IP address exported by a friend company to the White List. O (∩) O Haha ~ Happy

TIPS: whether it is dynamic blocking or IP blocking, this client will be refused.

This article is from the mail server and network management notes blog, please be sure to keep this source http://19281928.blog.51cto.com/2327194/598423