VPN and Proxy detection API:
Why You Need It and How to Get It




Many business owners today have the need to use VPNs (Virtual Private Networks) or proxy servers in order to shield their online activities from competitors, law enforcement, or other prying eyes. But how do you detect if people are using these anonymizing services? 

And how can you use this information to your advantage? 

This blog post will tell you all about these anonymizing services and offer a few different ways that you can use their detection in your own applications. 


WHAT ARE VPNS?

VPNs offer an encrypted connection from your computer to the internet, without sharing that information with any outside parties. With a VPN you can feel more secure when using public wifi or cellular networks, as well as have a shield against pesky advertisements. VPNs also allow for privacy by hiding your IP address. 

If you're trying to download something illegal (more likely on BitTorrent), the authorities could never find out who you are because all they would see is the VPN's IP address - not yours.


HOW TO TELL IF YOU ARE BEHIND A PROXY?

Different proxies use different protocols for connection, for example, a user might have a connection coming through an SSH proxy via ssl-tunnel or forwarded through an ssh tunnel. 

The easiest way to detect if and IP address is a Proxy or VPN is to use ProxyRadar.io. You can also perform manual checks on web interface. We offer free 1.000 queries per day.


THE IMPORTANCE OF DETECTING PROXIES

Proxy is an entity acting as an intermediary for another entity which means proxy is nothing but a computer that allows its user to connect with other computers. When it comes to corporations, the network administrator of the company assigns the proxy server for connecting with outside servers when internet access is blocked from inside of their company.


WAYS TO DETECT PROXIES FROM THE COMMAND LINE

The most popular approach is using Squid (the cache server). Squid has a module called external_acl which can be configured with a list of IPs that are either allowed or denied. The configuration file would include lines like the following:

http_access allow 192.168.0.5 http_access deny all

The external_acl module can be loaded by executing the following command on the cache server computer's terminal prompt: squid -zX .


HOW  TO DETECT PROXIES FROM PYTHON

1. Check if there are too many concurrent connections from a single IP address 

2. Compare the number of connections to the user’s bandwidth limit 

3. Check the time interval between connections, if it is short or very irregular this could be an indication of VPN usage


THE CONCLUSION

In a world of increasing security risks and hacks, staying safe while browsing the internet can be difficult. Thankfully, developers have created VPN and proxy APIs that can be implemented into any app or website to make the browsing experience safe, private, and secure. What do you think? Let me know by commenting below!