How to use PHP forms to prevent malicious crawler attacks

With the development of the Internet, the problem of malicious crawler attacks has become more common. So, how to use PHP forms to prevent malicious crawler attacks? This article will give you a detailed introduction.

First of all, we need to understand what a malicious crawler attack is. In short, malicious crawler attacks refer to using crawler programs to automatically access and crawl a large number of websites, causing problems such as excessive server load and network disconnection. This kind of attack will not only affect the normal operation of the website, but may also steal the website's private information.

In order to prevent malicious crawler attacks, we can use PHP forms. Below, we will introduce you how to use PHP forms to prevent malicious crawler attacks.

Step one: Set the maximum access time of the form

Malicious crawler attacks usually make a large number of visits to the website in a short period of time. To prevent this from happening, we can set the maximum access time for the form. After the form ends, if this time is exceeded, the program will automatically exit. This can effectively avoid malicious crawler attacks.

Step 2: Add verification code

Verification code is a simple but very effective way to prevent malicious crawler attacks. Before filling in the form, you are required to fill in a verification code. Only by filling in the correct verification code can the form be submitted. This ensures that only human users can use the form, and automated crawlers will fail the CAPTCHA.

Step 3: Verify HTTP referrer

HTTP referrer is the domain name information in the HTTP request header. We can verify the HTTP referrer to ensure that the person accessing the form is a user of this site. If the HTTP referrer is not this site, it can be determined to be a malicious crawler attack.

Step 4: Limit form submission frequency

Malicious crawler attacks often submit a large number of forms in a short period of time. We can prevent this type of attack by limiting the frequency of form submissions. For example, we can set up to only allow each IP address to submit the form once, or each user is only allowed to submit the form once per minute to limit the frequency of form submission.

Step 5: Record the log

Finally, we need to record the access log of the form for subsequent analysis. By recording form access logs, we can identify patterns of malicious crawler attacks and take measures to prevent them.

To summarize, in order to prevent malicious crawler attacks, we can set the maximum access time of the form, add verification codes, verify HTTP referer, limit form submission frequency and record logs. These methods can effectively protect your website from malicious crawler attacks.

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