IP/DNS Leaks: How to Check & Fix (UK, 2025)

What is a leak?

An IP leak or DNS leak happens when a website or service can still see your real IP address or your ISP’s DNS resolvers while you’re connected to a VPN. In the UK, this usually comes from mixed tunnelling (apps bypass the VPN), OS DNS caching, or browser features like WebRTC.

If you’re troubleshooting streaming errors, read these in tandem: Netflix UK with a VPN, BBC iPlayer with a VPN, and protocol tips in the UK VPN protocols guide.

Run the leak tests (3 steps)

1. Baseline (no VPN): disconnect the VPN → search “what is my IP” and note country/city and ISP. This is your control.
2. Connect VPN (UK server): repeat the IP check — you should now see a UK location and a VPN ASN, not your ISP.
3. DNS/WebRTC: run an extended DNS test and a WebRTC test in your main browser. You should not see your ISP resolvers or your local/private IP.

If you still see your ISP in the DNS list, that’s a DNS leak. Move to the fixes below.

Fixes by platform

Windows 10/11

• Enable the VPN’s DNS leak protection and kill switch in settings (see our Best VPN Settings (UK)).
• In Network & Internet → Adapter Options, ensure only the VPN adapter is active for the session; disable “metered” fallback networks.
• Flush caches: open cmd → ipconfig /flushdns.
• Browser: disable WebRTC leaks (see browser section below).

macOS

• Use the native VPN app (WireGuard/NordLynx preferred). Avoid manual IKEv2 unless you know DNS policy behaviour.
• Flush DNS: sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder.
• Check “Send all traffic over VPN” if using manual profiles; the app should enforce it automatically.

iOS/iPadOS

• Prefer the provider’s app profile (WireGuard/NordLynx or IKEv2). Reconnect if the device wakes from sleep.
• Disable “Private Relay” (iCloud) while testing — it can confuse DNS routes.
• Force-quit streaming apps after switching servers; they cache endpoints.

Android

• Enable Always-on VPN and Block connections without VPN (Settings → Network → VPN).
• Clear app data for streaming apps after server/protocol changes.
• If a captive portal (e.g., public Wi-Fi) breaks DNS, reconnect after sign-in or try OpenVPN TCP/443.

Browser WebRTC & DNS settings

• Chrome/Edge: use a privacy extension to restrict WebRTC local IP exposure. Consider DNS-over-HTTPS inside the VPN tunnel.
• Firefox: set media.peerconnection.enabled to false (advanced users) or use an extension; enable DNS-over-HTTPS if your VPN supports it.
• Safari: keep “Hide IP address from trackers” on; ensure the VPN app handles DNS, not your ISP.

Router & Smart TV considerations

Smart TVs and consoles often lack robust VPN apps and may keep regional caches. A router VPN routes them through the tunnel without per-app setup. The trade-off is lower peak speed on entry-level routers.

Guides: VPN Router Setup (UK) and overview VPN on a Router.

Streaming reliability (Netflix UK, BBC iPlayer)

Even a tiny leak can trigger proxy errors. After fixing leaks, follow the UK streaming playbooks: Netflix UK guide and BBC iPlayer guide. If a network is fussy, switch to OpenVPN TCP/443 as in our protocols guide.

Video: Quick leak test & fix (UK)

FAQ

What’s the difference between an IP leak and a DNS leak?

IP leak exposes your real IP; DNS leak reveals your ISP’s resolvers. Either can break privacy or streaming.

Will changing protocol help?

Yes. WireGuard is fastest; OpenVPN TCP/443 often stabilises routes on strict networks.

Do I need to tweak my router?

Only if you run a router VPN or have odd DNS behaviour. See our router setup guide.

Does DoH/DoT matter if I use a VPN?

It can — but ensure DNS still resolves inside the tunnel, not via your ISP.