When you mail a letter, you write down the delivery address, as well as your address, and pass it off to the post office to deliver. They will pass your letter on to the post office next door, and so forth, until it arrives to your recipient. In the same way, when you request a page on the internet, you give the IP address of the webpage, your own IP address, and the contents of your request to your Internet Service Provider (ISP), who passes it along until it reaches its destination.
In our mailing analogy, a VPN is analogous to a PO box. Instead of sending your letter directly, you wrap it in another letter which you send to your VPN. When the VPN receives the letter, they sends it onwards, listing themselves as the return address. When the response arrives, they forward it back to you. Therefore, your ISP does not know who is receiving your messages, and the person receiving your message does not know who sent them. Three common reasons to use VPNs are to evade internet censorship, avoid invasive ad tracking, and accessing region blocked content.
Unfortunately, if someone looks carefully, it is easy to tell if you are using a VPN, and both your ISP and the site you want to connect to could refuse to serve you. PenguinProxy solves this with a peer-to-peer approach. Instead of requesting pages ourselves, and revealing that you are using a VPN, we have our users deliver requests for each other. Other P2P VPNs with this approach have security issues, because they expose your computer files to the internet, the equivalent of letting strangers into your house. Instead, we hold requests on our own servers for the PenguinProxy client to request, keeping the benefits of P2P while limiting the ability for other users to affect your computer. We have no access to modify your files, and whether or not you complete the requests you pick up is up to you (although it affects your reputation and service).
In our next post, we will describe how different PenguinProxy work at a more technical level.