How to Prevent emails from being sent by only logging on to a specific email address on a computer and receiving emails on a computer to protect the security of computer files

How to Prevent emails from being sent by only logging on to a specific email address on a computer and receiving emails on a computer to protect the security of computer files
Sometimes we are considering computer file security. We need to prohibit computers from sending emails, especially emails with email attachments, to prevent computer confidential information from being leaked through emails. However, sometimes at work, we also need to allow computers to receive emails. This makes many enterprise network administrators struggle. After all, the more detailed the network management, the more difficult it is to achieve.
 
Although packet capture can theoretically prevent the computer from sending emails to the Internet and allow the computer to receive emails. However, due to the large number of Internet mailboxes, and many mailbox transmission protocols are frequently changed, more and more mailboxes are sending and receiving emails through HTTPS encryption protocol, therefore, packet capture is almost impossible to completely prevent email sending.
 
Is there a simple and effective way to prohibit the computer from sending emails? This article uses a computer security software to teach you how to cleverly prohibit computers from sending emails and allow computers to receive emails.
 
First of all, we need to download a "portable to USB port management software" (: http://www.grabsun.com/monitorusb.html), this is a computer to prohibit the use of U disk, disable the USB storage device software, this prevents computer files from being leaked through USB storage devices. At the same time, it can also prohibit computers from sending emails, uploading computer files to online storage, sending files via QQ, uploading FTP files, and so on, to prevent leaks through the network. The administration software for connecting to USB port is very easy to use. You only need to click the check box. As shown in:
Figure: Functions of butler to USB port management software
In this way, we can completely prohibit USB storage devices, prohibit email sending, prohibit logon to the network disk to upload computer files, prohibit FTP to upload computer files, and prohibit QQ to send files, thus fully protecting the security of computer files.
 
At the same time, even if you disable email sending by computer, you can still set to allow only specific email addresses to be logged on (for example, you can only log on to the company's internal email address and disable Internet email addresses ), that is, set the "email whitelist" to facilitate the need to send and receive emails at work.

This requires the use of the program exception mechanism (that is, the whitelist program) that is integrated with the USB control system. The details are as follows:
 
Click "disabled programs", and then click "set banned Programs list". The mailbox to be excluded can be added here. For example, if you want to exclude the QQ mailbox, you only need to add the "Mailbox * QQ mailbox *", so that you can only log on to the QQ mailbox, but other mailboxes still cannot log on. As shown in:

Figure: only logging on to a specific mailbox
In addition, you can disable email sending by sending emails to a specific mailbox, further protecting the security of computer files without affecting the work needs of receiving emails in some cases. However, in this case, you cannot log on to the mailbox of the web edition for setting, but you need to use the mailbox client software. The following uses Foxmail as an example to describe how to disable email sending only on the computer. The specific settings are as follows:
 
Click "disabled programs", click "set banned Programs list", and then add "email writing" here, in this way, only emails can be received after Foxmail is opened, but emails cannot be written (once the client writes an email or replies to the email, it will be closed in real time), as shown in:
Figure: only sending emails is prohibited
In short, there are many ways to prohibit sending emails to a LAN Computer, allow logging on to a specific mailbox, enable only a specified mailbox, or even allow only the computer to receive emails and prohibit sending emails to the computer, however, it is easier to implement it through some network control software. Enterprises and institutions should decide based on the specific situation.