What is the cause of 403 errors encountered by crawlers using proxy IP?

With the development of the Internet, more and more websites have adopted security policies to prevent malicious crawlers from accessing and data misuse. Therefore, when crawling with proxy IP, it is very likely that you will encounter a 403 error, that is, the server denies the access request of the crawler. The reasons why crawlers encounter 403 errors when using proxy IP are explained in detail below.

Possible causes of the error message returned by the proxy server:

The short-term request API interface extracts IP too frequently, which is denied by the firewall. In order to protect the target website and maintain the quality of service, some proxy servers restrict the IP addresses that frequently request the same API interface. Such restrictions are designed to prevent too frequent visits and to avoid overloading the target website. When a crawler uses the proxy IP to make a high frequency request, it may trigger the firewall mechanism of the proxy server, resulting in a 403 error. To solve this problem, the risk of being blocked can be reduced by reducing the frequency of requests, rotating multiple proxy IP addresses, and so on.

Authorization failure: In authorization mode, the proxy server requires the terminal IP address for authentication. If the proxy IP changes or does not match the terminal IP, the connection to the proxy server cannot be successful, resulting in a 403 error. This can happen when using dynamic proxy IP, where the IP address is constantly changing. In order to avoid authorization failures, you can confirm the authorization mechanism with the proxy provider to ensure that the proxy IP is properly used and updated.

DNS analysis error: The proxy server needs to resolve the DNS address of the target website. If the proxy server cannot resolve the DNS address of the target website correctly, a valid connection cannot be established, resulting in the failure to access the target website and triggering a 403 error. This may be due to incorrect proxy server configuration, network issues, or problems with the DNS Settings of the target site. To solve this problem, you can try using another reliable proxy server or contact the proxy provider for technical support to ensure that DNS resolution is performed properly.

By understanding the possible causes of the error messages returned by the proxy server side, we can better understand the reasons behind the 403 errors encountered by crawlers using the proxy IP. For different reasons, we can take corresponding measures to solve the problem, so as to improve the stability and efficiency of the crawler.

Possible causes for the error message returned by the server of the target website:

This proxy IP is restricted by the target site: Some target sites will restrict certain proxy IP, especially those that are considered to be malicious crawlers. If you use a proxy IP that happens to be on the target site's restricted list, a 403 error will be returned when you access the target site. This limitation may be based on IP addresses, user behavior, or other metrics. To solve this problem, try using another proxy IP that is available, or communicate with the target website to gain access.

Frequent visits to the target website: Frequent visits to the target website in a short period of time, exceeding the frequency limit set by the target website, may be identified as malicious access by the target website, and then trigger 403 error. To avoid this, you can reduce the frequency of access, set reasonable access intervals, or rotate multiple proxy IP addresses to simulate normal user behavior.

Firewall Denied access: The firewall system of the target website may detect high frequency requests or abnormal behavior and flag the proxy IP as a risk IP, thus denying access requests. This is usually done to protect the security and stability of the target website. To solve this problem, try to visit less frequently, use a different proxy IP, or contact the target site administrator for more information and support.

HTTPS Website access problem: Some target websites use HTTPS for encrypted communication. If you use a proxy IP that does not support HTTPS access, you will get a 403 error when you try to access an HTTPS website. To solve this problem, you can choose a proxy IP that supports HTTPS access, or obtain data from the target website by other means, such as using a proxy IP to connect to a non-encrypted HTTP version of the website.

DNS resolution error: The domain name of the target website fails to be resolved. As a result, the target website cannot be accessed. This may be due to a network issue, a misconfiguration of the target website's DNS, or other factors. To resolve this issue, try using another reliable proxy IP or wait for the DNS issue of the target website to be fixed.

Target website server load is too high: If the target website's server load is too high to respond to the crawler's request in a timely manner, a 403 error will be returned. This usually occurs on websites with heavy traffic or limited server resources. To solve this problem, you can try to reduce the frequency of access, optimize the way the crawler requests, or choose to access during off-peak hours.

IP is intelligently blocked by the server: The server uses intelligent algorithms to detect abnormal request patterns, and if it detects that too many requests are sent from the same IP address, it may be intelligently blocked by the server, resulting in 403 errors. To avoid this, the crawler's access rules can be adjusted to avoid excessive requests, or multiple proxy IP rotations can be used to spread out requests and simulate normal user behavior.

There are a variety of reasons why crawlers encounter 403 errors when using proxy IP. In order to solve this problem, we can take some countermeasures, such as changing the proxy IP, reducing the frequency of access, using the proxy IP that supports HTTPS, optimizing the abnormal request pattern, etc., to ensure that the crawler can normally visit the target website and obtain the required data.