Internet threats and vulnerabilities are risks every internet user should be ready to encounter, mitigate, and even avoid. Most of the vulnerabilities arise from various factors, but many are due to weaker internet security and poor privacy protection mechanisms. To prevent this, many internet users around the world are using anonymizers and VPNs for internet security and privacy.
隐私 VPN
A VPN achieves privacy by changing your IP address – the unique numeric address that identifies a device on a network. A VPN does this by assigning you a virtual IP address when you connect to one of the VPN servers. With the virtual IP address, any tracking and identification will end at the VPN’s doors.
IP 泄露及其发生方式
一言以蔽之，IP 泄露是指在某些特定情况下，你被屏蔽的 IP 被泄露。即使你受到 VPN 的保护，IP 泄露也会以多种方式发生。我们将探讨三种主要的方式；
- WebRTC 错误
网络实时通信（WebRTC）是浏览器使用的一种接口或标准，可通过聊天、视频通话甚至文件共享实现实时通信。除了有用之外，WebRTC 本身也有缺陷，攻击者或任何人都可能利用它来窥探你的隐私。这是因为，要进行 WebRTC 通信，即使使用了 VPN 或任何匿名程序，网站也可以直接确定设备的实际 IP 地址。要防止这种 IP 泄露，必须在浏览器中禁用 WebRTC 服务。此错误会影响 Google Chrome、Mozilla Firefox 和 Opera 浏览器。
- IPv4 和 IPv6 DNS 泄露
Internet Protocol Version 4(IPv4) is an addressing standard that is used to define devices on the internet based on their IP addresses. Since the internet has been expanding, IPv4 addressing was getting maxed out hence another standard, IPv6 was put in place. When using a service such as a VPN to hide your IP address, the operating system (OS) can get confused when sending IPv4 requests. This confusion makes the OS resolve the issue by using the default DNS server sometimes the one offered by your ISP, and this leads to a leak.
IPv6 泄露也会发生，但不是因为操作系统，而是因为大多数 VPN 不支持 IPv6，因此无法对 IPv6 请求进行隧道传输。你的 ISP 最终会为它们提供服务，这也会导致泄漏。
- VPN 连接中断
This is the simplest form of IP leaks, and it happens when your VPN connection drops. When this happens, it is as if you are surfing the internet normally and anybody can see your IP address. To avoid this, use a kill switch. Most VPNs provide this feature, and it cuts all the outbound/inbound traffic when a VPN connection drops.
从以上几种方法来看，你很难知道自己是否遭遇了 IP 泄露。不过不用担心，有一个简单的程序可以让你知道自己的 IP 是否已经泄漏。步骤如下；
- Before using any VPN or anonymizer, go to any website that checks for IP addresses and writes your own down.
- 现在连接到 VPN 服务器，然后重新访问 IP 网站，看看显示的 IP 地址是什么。它应该会自动变成与你连接的服务器相对应的那个。
如果步骤 2中显示的 IP 地址与 VPN 分配的地址相似，则说明你的 IP 没有泄漏。如果与步骤 1 中的地址相同，那么要么是你的 VPN 连接尚未通过，要么是你的 IP 地址泄露了。
