You check your IP address today and it’s different from yesterday. That’s normal. Here are the reasons — and what to do if you need an address that stays put.
Dynamic addresses are the default
Most home and mobile connections receive a dynamic public address from the provider’s pool, using DHCP or PPP. The assignment is a lease: when it expires, or when your router reconnects, you may get a different address. Providers do this because it lets them manage a limited pool of IPv4 addresses efficiently.
Common triggers:
- restarting or re-plugging your router;
- a power or line interruption;
- the provider’s scheduled reconnection (some ISPs force one every 24 hours);
- moving between Wi-Fi and mobile data.
Mobile networks change more often
On mobile data, your public IPv4 address is usually a carrier-grade NAT address shared with other customers, and it can change whenever your phone reconnects to the network — sometimes several times a day.
IPv6 changes by design
With IPv6, your network’s prefix (usually /56 or /64) may stay the same for long periods, but your device’s own address changes regularly. Privacy extensions (RFC 8981) generate temporary interface identifiers so websites can’t follow a device using a stable address. Some ISPs also rotate the prefix itself.
VPNs and privacy relays
When a VPN, Tor or a privacy relay is active, websites see the address of the exit server. Switching servers — or the service doing it for you — changes your apparent IP.
Do I need a static IP?
Usually not. A static address is useful if you:
- host a service at home (a server, VPN endpoint or camera system);
- need to be allow-listed by a company firewall or API;
- run email servers, which need matching reverse DNS.
Options: ask your ISP for a static IPv4 address (often a paid add-on), use IPv6 with a stable prefix, or use dynamic DNS to keep a hostname pointed at a changing address.
Check what you have
The homepage shows your current IPv4 and IPv6 addresses, the network they belong to and whether the address belongs to a mobile or hosting network. Compare it with your router’s WAN address to see whether you’re behind CGNAT.