Your VPN app says "Connected". That tells you a tunnel exists. It does not tell you that all of your traffic is using it. These five checks take about two minutes and confirm that your VPN is doing its job.
Check 1: Your IP address changed
- Turn the VPN off and visit any "what is my IP" page. Note the address and location.
- Turn the VPN on and refresh.
The address and location should now belong to the VPN server. If they did not change, your traffic is not going through the tunnel. Reconnect, or try a different server.
Check 2: No DNS leak
DNS is how your device turns names like example.com into addresses. If DNS lookups bypass the VPN, your internet provider still sees every site you visit, even though the rest of the traffic is encrypted.
Run a DNS leak test with the VPN on. The servers listed should belong to the VPN provider, not to your ISP or mobile carrier. If you see your ISP:
- check your VPN's settings for a DNS or "leak protection" option;
- on Android, set Private DNS to Automatic while testing;
- reconnect and test again.
Check 3: No WebRTC leak
WebRTC lets browsers make video and voice calls. It can reveal your real IP address to websites even when a VPN is on.
Run a WebRTC leak test in the browser you actually use. Only the VPN's address should appear. If your real IP shows up, use your browser's WebRTC setting or an extension to limit it, or use your VPN's WebRTC protection if it has one.
Check 4: No IPv6 leak
Some networks give your device an IPv6 address. If your VPN only tunnels IPv4, IPv6 traffic can go around it.
A leak test that checks IPv6 should show either the VPN's IPv6 address or no IPv6 connectivity at all. If it shows your provider's IPv6 address, look for an IPv6 option in your VPN, or disable IPv6 on that network.
Check 5: Behaviour when the connection drops
Switch from Wi-Fi to mobile data, or briefly toggle airplane mode. Two things should happen:
- the VPN should reconnect on its own;
- if it has a kill switch, traffic should stop while it is disconnected rather than leaking out.
On Android, enable Always-on VPN and Block connections without VPN in the system VPN settings for the strongest protection.
Bonus: speed check
Run a speed test with the VPN off, then on, using a nearby server. A modest drop is normal. A large one usually means the server is far away or busy: switch to a closer one.
What the results mean
- IP did not change: traffic is not in the tunnel. Reconnect or change server.
- Your ISP's DNS servers appear: DNS leak. Enable leak protection, set Android Private DNS to Automatic.
- Your real IP appears in the WebRTC test: browser leak. Limit WebRTC in the browser.
- Your provider's IPv6 address appears: IPv6 leak. Enable the VPN's IPv6 handling or disable IPv6.
- Traffic flows while the VPN is down: no kill switch. Enable the kill switch or Always-on VPN.
How often should you test?
Once when you set up a VPN, after major app or system updates, and whenever you start using a new network type, such as a new mobile carrier or a hotel network.
Leak tests built in
You should not have to hunt for testing sites. Korp VPN includes a DNS leak test, a WebRTC leak test, a speed and latency test and a live Privacy Score directly in the app, alongside unlimited data, a strict no-logs policy on RAM-only servers and a stealth protocol for restrictive networks. Plans are $4.99 for three months or $17.99 a year.