Reject spam: Three "weapons" are broken

Spam, spam, or spam. Do you encounter annoying spam when you open your mailbox every day? Is there any good way to say "no" to spam? We will introduce three friends to help you. One is Microsoft's mail server software Exchange. I believe most enterprises with independent mail servers already have it; the other is the KV Jiangmin anti-virus Wang online edition for Exchange launched by Jiangmin technology. The last is the free Domestic Client mail Receiving Software Foxmail. They're all familiar to you!
It should be noted that all spam emails that are harmful to users or that cause interference should belong to spam. Therefore, concerning the prevention of mail viruses, the prevention of DOS attacks on mail servers, and the filtering of junk mails in the general sense, we should all be included in how to prevent spam.

Email Anti-Virus

First, install the KV anti-virus king on the Exchange mail server and enable this function. When the mail server receives an email with a virus, it filters out the virus in real time and sends two Emails: one to the original sender, with the topic KV to detect the virus, and the other to the recipient, after a virus-infected attachment is filtered out, it becomes a virus analysis document that lists the virus name, clearing date, Sending address, and other information. A line of prompt text is attached to the body of the email, indicating the attachment name, virus name, and processing result (1 ). In this way, all viruses from emails will no longer enter your mailbox, but will be filtered out before entering the email server.

　　
Block virus emails

If you still need to pay for implementing this anti-virus function, the following two security measures will be totally unexpected.

Defense Against DOS

DOS (Denial of Service Attack) has become the biggest killer of many email servers for some time. The principle of denial of service (DoS) attacks on the mail server is that it constantly sends a large number of emails to the mail server until the maximum capacity is exceeded and crashes. Denial of Service attacks are sometimes not targeted hacker behavior. Nowadays, viruses often use their own SMTP engine to send a large number of emails to addresses infected with computers. If SMEs think that their companies are small and will not become targets, this idea is no longer realistic. For small and medium-sized enterprises, it is easier to prevent DOS attacks than large enterprises, because small enterprises often do not have too many emails. We can limit the number of emails for each connection according to the size of the business volume, and the number of recipients of each email. In this way, the user can discover and take measures as soon as possible for DOS attacks, instead of waiting until the server crashes to find that the user has implemented DOS attacks (2 ). In addition, Exchange also supports filtering, such as blocking emails with specific addresses or empty senders.

 

　
DOS restrictions

Content Filtering

Currently, it is not possible to identify which email is junk or which is a valuable commercial email. If you clear a commercial email as a spam, it is obviously not worth the candle. Foxmail provides a mail filtering function, which enables you to preliminarily filter out spam emails with frequent and specific content. The specific implementation method is as follows: open [account] → [filter], and press "new" in the blank interface, a new filter is created.

 

Email operation

Find the regular text that appears in the spam, and fill in the filtering conditions as shown in the following figure based on the logical relationship between the location and the corresponding logic, and select the location where the characteristic text appears, such as the recipient, sender, topic, and attachment. Fill in the corresponding content according to a certain logical relationship, and then press "action" to select a processing result that you think is appropriate, such: "Delete directly from the server", "Send text message", "transfer", etc. If you think it is a better solution, you can initially get rid of spam troubles (3 ).

Of course, for network security, preventing spam is only a small part. To prevent the overall network security, you need to carefully filter your own security products based on your actual needs.