1. Understand the role and risks of proxy IP

Proxy IP is a network transit service that can hide the user's real IP address and increase the anonymity and security of network requests. However, proxy IP also has certain risks. First, due to the transit characteristics of proxy IP, its transmission speed may be slow, affecting the user experience.

Second, some unstable proxy IPs may be identified and blocked by websites, resulting in the rejection of users' network requests. Therefore, when using proxy IP, we need to weigh the pros and cons and take corresponding measures to reduce risks.

2. Choose a suitable proxy service provider

Choosing a proxy service provider with a good reputation and stable service quality is the first step to prevent IP from being blocked. When choosing, we can refer to factors such as the evaluation of other users, the reputation of the service provider, and the stability of the service. 

Avoid choosing proxy service providers that provide free or low-quality services, because their IP resources may be unstable and easily identified and blocked by websites. At the same time, we should also pay attention to the update and maintenance capabilities of the service provider to ensure the stability and availability of the proxy IP.

3. Avoid frequent IP changes

Frequent changes of proxy IPs can easily alert the target server, thereby increasing the risk of being blocked. Therefore, it is recommended that users maintain a stable IP address for a relatively long period of time. Of course, this does not mean that we cannot change the IP, but we should change it at the right time. 

For example, when our crawler encounters a large number of requests being rejected or the access speed is significantly slowed down, we can consider changing to a new proxy IP.

4. Reasonably set the request frequency

Whether using a proxy IP for crawling or other operations, you need to set the request frequency reasonably. Excessive request frequency can easily be regarded as an attack and cause the IP to be blocked. In order to reduce the risk of being blocked, we can take the following measures:

Use delays or intervals to control the time when the request is sent to simulate human browsing behavior. This makes our requests look more natural and reduces the risk of being identified.

Randomize the request interval and request order. Do not send requests at fixed time intervals or in a fixed order, which can increase the difficulty of identifying the website.

Limit the number of concurrent requests. Too many concurrent requests will increase the burden on the server and easily arouse the website's vigilance. Therefore, we need to set the appropriate number of concurrent requests according to the actual situation of the target website.

5. Use proxy pools and IP rotation

A proxy pool is a tool for managing a large number of proxy IP addresses. It can obtain proxy IPs from multiple channels and provide interfaces for crawlers to use. Using a proxy pool allows us to obtain and use proxy IPs more conveniently while reducing the risk of being blocked. 

In addition, we can also use IP rotation to prevent being blocked. The principle of IP rotation is to continuously switch IP addresses over a period of time to bypass the website's blockade. This requires us to write corresponding code to achieve automatic switching and management of IPs.

6. Simulate human behavior

Websites usually determine whether they are crawlers based on the user's behavior pattern. In order to simulate human behavior, we can take the following measures:

After accessing the page, simulate human click and scroll behaviors, such as clicking links, scrolling pages, etc. This can be achieved by writing corresponding code.

Use browser automation tools, such as Selenium, to simulate a real browser environment. This can make our network requests look more real and credible.

Pay attention to handling exceptions and errors. When our crawler encounters an exception or error, we should handle it in time and give the corresponding prompt information, rather than ignoring or skipping it directly.

VII. Comply with laws, regulations and website rules

Finally, we need to emphasize the importance of complying with laws, regulations and website rules. When using proxy IPs for network requests, we must comply with local laws and regulations and the website's crawler rules and restrictions. No illegal activities or malicious attacks may be carried out, otherwise not only will the proxy IP be blocked, but you may also face legal prosecution.

In summary, preventing websites from detecting and blocking proxy IPs requires comprehensive consideration and practice from multiple aspects. 

Choosing a suitable proxy service provider, avoiding frequent IP changes, reasonably setting request frequency, using proxy pools and IP rotation, simulating human behavior, and complying with laws, regulations and website rules are all effective anti-blocking strategies. Only by combining these strategies can we better protect our proxy IPs from detection and blocking.