Dynamic vs Static IP (+ CGNAT): Why Your IP Won’t Change and What to Do

Trying to change your IP address by restarting your router—only to find it stays the same? The answer usually comes down to dynamic vs static IP and something many people don’t realize exists: CGNAT (Carrier-Grade NAT). This guide explains what’s happening and what your real options are.

Dynamic IP vs static IP (the core difference)

• Dynamic IP: your ISP can change your public IP over time (common for home connections).
• Static IP: your ISP reserves a specific public IP for you (common for business plans or paid add-ons).

Why your IP sometimes changes (and sometimes doesn’t)

With a dynamic IP, your ISP assigns an address using a “lease.” Restarting your router might result in a new IP, but many ISPs will give you the same IP again unless the lease expires or the pool changes.

Common reasons you keep getting the same IP

• Your lease hasn’t expired, so the ISP reassigns the same IP.
• Your ISP uses sticky assignments tied to your modem/router identifier.
• You’re on CGNAT, so changes aren’t visible the way you expect.

What is CGNAT (Carrier-Grade NAT)?

CGNAT means your ISP puts many customers behind shared public IP addresses. Your home still has a private WAN address, and the ISP performs NAT at the carrier level. This is increasingly common due to IPv4 exhaustion.

How CGNAT affects you

• Port forwarding often won’t work for remote access (unless the ISP provides a workaround).
• Your “public IP” may appear shared or change behavior unexpectedly.
• Some services may rate-limit or flag shared IP ranges.

How to change your IP (realistic options)

Option A: Use a VPN (fastest)

A VPN replaces the public IP websites see with a VPN server IP. This is the quickest way to “change” your public IP for browsing and apps.

Option B: Ask your ISP for a real static IP

If you need inbound access (hosting, remote desktop, servers), a static IP is often the cleanest solution—especially if you are on CGNAT.

Option C: Wait longer than a quick reboot

Some ISPs require you to disconnect for longer (e.g., 30–60 minutes or more) before a lease changes. There’s no universal rule.

Option D: Change networks (temporary)

Using a mobile hotspot or a different Wi‑Fi network gives you a different public IP immediately.

When you should NOT chase an IP change

• If your goal is privacy: use a VPN instead of trying to “cycle” ISP IPs.
• If you’re trying to fix geo issues: read why IP location can be wrong.