VPN Connected but No Internet on Windows — 10 Advanced Fixes for Both Corporate VPNs and Personal VPN Apps (Plus MTU / Kill Switch / Proxy)

You turn on the VPN… and everything dies.

Wi-Fi still says “connected,” but:

  • your browser shows “Can’t reach this site”

  • messengers go offline

  • work stops immediately

Most people assume the VPN server is down.
In real-world troubleshooting, more than half of these cases are not server outages — they’re routing, DNS, adapter, or app features (Kill Switch) causing a local conflict the moment the tunnel comes up.

This guide doesn’t start with reinstalling.
We’ll remove causes in a clean order: app settings → protocols → routing → DNS/proxy → metrics → drivers.

First check: Is the internet normal when VPN is OFF?

Confirm this exact pattern:

  • VPN OFF → internet works

  • VPN ON → internet breaks

If yes, your router/ISP is probably fine. The VPN connection is changing your network path.

👉 If internet is unstable even with VPN OFF, fix the baseline first:
[Wi-Fi Connected but No Internet — Step-by-Step Fix]

1️⃣ Identify what kind of VPN you’re using (corporate vs personal)

This changes where the “real switch” is.

Corporate VPN

  • used for intranet/internal systems

  • strict policies

  • may force all traffic through the tunnel

Personal VPN app

  • privacy / geo access

  • app options (Split Tunneling, Kill Switch) matter a lot

👉 Corporate VPN problems often live in Windows routing/adapter settings
👉 Personal VPN problems often live in the VPN app’s toggles

2️⃣ Check Split Tunneling — and make sure the Kill Switch isn’t stuck (personal VPNs)

Split Tunneling decides whether:

  • only corporate traffic goes through VPN, or

  • everything goes through VPN

If Split Tunneling is off, normal websites may be forced into the tunnel and get blocked by policy/firewalls.

Now the big one for personal VPNs: Kill Switch.
Kill Switch is designed to block internet if VPN drops — but sometimes it “sticks” after a crash or flaky connection and keeps blocking everything.

Do this:

  • Open your VPN app settings

  • Find Kill Switch (may be called “Network Lock”)

  • For testing, temporarily set it OFF

  • Disconnect VPN → reconnect VPN → test browsing

👉 If turning Kill Switch off immediately restores internet, you didn’t have a routing problem — you had a safety feature stuck in “block mode.”

3️⃣ IPv6 conflict (the hidden boss in modern VPN failures)

This is extremely common now.

Why it happens:

  • ISPs push IPv6

  • many VPN tunnels behave like IPv4-only

  • traffic gets misrouted

Quick test:

  • Control Panel → Network Connections

  • Right-click your VPN adapter → Properties

  • Uncheck Internet Protocol Version 6 (TCP/IPv6)

  • Reconnect VPN

If it works, you removed a protocol mismatch, not a server issue.

4️⃣ Corporate VPN users: disable “Use default gateway on remote network”

If this is enabled, Windows may force all internet traffic through the VPN tunnel.

Go here:

  • Control Panel → Network Connections

  • Right-click your VPN connection → Properties

  • Networking → IPv4 → Properties → Advanced…

  • Uncheck Use default gateway on remote network

Reconnect and test again.

5️⃣ DNS issues — and proxy leftovers (VPN connects, but websites won’t load)

If VPN stays connected but:

  • websites don’t load

  • only certain sites fail

  • pages hang forever

…DNS or proxy settings are common culprits.

DNS quick test

Try a known public DNS:

  • Google DNS: 8.8.8.8 / 8.8.4.4

  • Cloudflare: 1.1.1.1 / 1.0.0.1

Then run:

ipconfig /flushdns

Proxy leftover check (surprisingly common)

Some VPNs set a proxy and fail to revert it after a crash.

Check this:

  • Settings → Network & Internet → Proxy

  • Make sure Use a proxy server is OFF

👉 If this was ON, it can break browsing even when VPN looks “fine.”

6️⃣ Adapter priority (Metric) problems — Windows picks the wrong path

After installing a VPN you typically have:

  • your real Wi-Fi/Ethernet adapter

  • one or more virtual VPN adapters

If Windows chooses the wrong preferred route, internet can appear dead even though VPN says “connected.”

Fix test:

  • Control Panel → Network Connections

  • Right-click VPN adapter → Properties

  • IPv4 → Properties → Advanced…

  • Uncheck Automatic metric

  • Set Interface metric = 1 (low number)

📌 Lower metric = higher priority.

Pro Tip: Check MTU Size (when sites load halfway, then freeze)

This one explains the classic symptom:
VPN connects, some sites open, then loading stalls or large uploads fail.

VPN adds overhead (extra headers).
If your connection still sends full-size packets (often MTU 1500), some packets can exceed the path limit and get fragmented or dropped.

What to try:

  • In your VPN app settings (if available), lower MTU from 1500 to:

    • 1400 (common stable value)

    • or 1350 (more conservative)

👉 This alone can fix stability and speed on flaky routes.

(If your VPN app doesn’t expose MTU settings, don’t force it here — keep moving. Corporate clients vary a lot.)

7️⃣ Repair the virtual adapter driver (TAP/TUN) when it’s corrupted

Often the VPN app is fine; the virtual driver is broken.

Common names:

  • TAP-Windows Adapter

  • TUN / Wintun

  • vendor virtual adapters

Fix:

  • Device Manager

  • find the TAP/TUN adapter

  • right-click → Uninstall device

  • reboot

  • repair/reinstall the VPN app

8️⃣ Reset the Windows network stack (safe deep reset)

When the Winsock stack is tangled, this clears it.

⚠️ Save work first. Some apps may require re-login afterward.

Run CMD as Administrator:

ipconfig /flushdns
netsh winsock reset

Reboot after.

9️⃣ Firewall / endpoint security conflicts (corporate PCs especially)

On corporate devices you may have:

  • VPN client

  • endpoint security agent

  • firewall rules
    …all inspecting traffic.

Testing rules:

  • only test changes on a trusted network

  • don’t permanently disable corporate security tools yourself

  • bring evidence to IT (next step)

🔟 What to tell IT (this gets real help faster)

Instead of “VPN doesn’t work,” report what you tested.

Use this:

“VPN connects, but internet dies immediately after. I tested IPv6 off, default gateway on remote network off, DNS + proxy check, adapter metric priority, MTU lowering (if supported), and refreshed the TAP/TUN adapter.
Can you verify my policy (split tunneling / routing rules), and IP pool assignment?”

If you can add timestamps, do it:

  • “It happened at 10:15 AM and 2:30 PM today.”

👉 Timestamps + your test list pushes IT straight to logs and policy instead of guessing.

Wrap-up (what this usually is)

VPN “connected but no internet” usually comes down to:

  • Split tunneling / Kill Switch behavior (personal VPNs)

  • IPv6 vs IPv4 mismatch

  • default gateway forced through VPN

  • DNS or proxy leftovers

  • adapter priority (metric) confusion

  • MTU size mismatch

  • virtual adapter (TAP/TUN) driver issues

Follow the order above and you’ll avoid the worst pattern:
reinstalling repeatedly without fixing the actual conflict.

👉 This guide is also available in Korean.
It explains the same issue with localized, Korean-language instructions.
[VPN을 켜면 인터넷이 안 될 때 – 회사 VPN·개인 VPN 공통으로 해결하는 윈도우 심화 점검 10단계]