Proxies for Web Scraping and Beyond
Warning: Work in progress!
When dealing with web scraping, networking, or distributed systems, proxies are an essential tool. They help manage traffic, provide anonymity, and bypass restrictions. In this post, I’ll break down what proxies are, why they matter, and how you can use them effectively.
What is a Proxy?
A proxy server is an application that acts like an intermediary (middleman) between a client and a server. When your application sends a request for data, the request goes through the proxy server first. This has several benefits:
- Anonymity: The server sees the proxy’s IP address instead of your actual IP address.
- Security: Proxies can filter requests, block unwanted traffic, and add an extra layer of protection.
- Privacy: They help keep your real identity and location hidden.
Why Use Proxies in Web Scraping?
Imagine you have a web scraping application that makes a large number of requests to a target server to gather data. Many websites—like Amazon, Indeed, LinkedIn, etc.—have anti-bot systems to prevent automated data extraction. These systems monitor the traffic and, if they detect too many requests coming from the same IP address, they may block that IP. That’s where proxies come in.
By routing your requests through a proxy, you can distribute the load and reduce the chance of your scraping bot getting blocked. This allows you to scrape data more efficiently and reliably.
The Role of Reverse Proxies
Another common use of proxies is as a single entry point for all external requests to a web server. In this case, the reverse proxy’s IP address is stored in DNS records, and tools like Nginx often serve as the reverse proxy. In addition to forwarding requests, Nginx can also handle load balancing and caching, making it a popular choice in production systems.
Use of Multi-Layered Proxies
With the recent advances in anti-bot technology, using a single proxy is often not enough. A single point of failure can reveal your client’s IP or get the proxy blocked. Multi-layered proxies take this one step further by creating a chain of proxies, adding additional layers of anonymity and protection.
Why Multi-Layered Proxies?
Enhanced Anonymity: Each proxy in the chain only sees the previous hop’s IP, making it much harder to trace back to your client.
Increased Reliability: With multiple layers, even if one proxy is blocked, others can keep the traffic flowing.
Regional Flexibility: You can choose different regions for your outer and inner layers. This is important because some websites display region-specific content or block requests from unexpected regions.
Setting Up a SOCKS Proxy on Amazon Linux EC2
Step 1: Launch Your EC2 Instances
Log in to the AWS Management Console and launch a few EC2 instances using the Amazon Linux AMI.
Choose the free tier eligible instance type (like t2.micro) to keep costs low.
Save your key pair securely (e.g., in a folder like ~/proxy/keys), and note down the public IP addresses. You might store these IPs in a config file (say, proxy/public-ips.config) for easy access.
Step 2: Configure Each Instance
Once your instances are up:
Log in using SSH:
ssh -i ~/path-to-your-key.pem username@<instance-public-ip> -D port -N -C
Ensure SSH is set to allow dynamic port forwarding. (Optional, do if nothing seems to work)
On Amazon Linux, the default SSH configuration usually allows this, but you can check the /etc/ssh/sshd_config file to confirm that options like AllowTcpForwarding are enabled.
Configure your system to use the proxy
I’d prefer using Firefox and entering the proxy details in there, as windows default settings are a pain to configure. Just enter 127.0.0.1 as ip and port that you have used.
Till here we have configured a single proxy server, now I’ll show you how to make multi layer proxies for improved privacy while crawling.