If you have ever opened your network settings and seen an address like 192.168.1.5, while an IP-checking site showed a completely different address — that is not a mistake. This is how the gray and white IP pairing works, and understanding it helps anyone who configures a server, a router, or a home network, rents a VDS, or tries to understand why their computer cannot be reached directly from the internet.
What a white and gray IP address are
A white (public) address is visible directly from the internet: any external host can reach the device through it. A gray (private) address works only inside a local network — a router, a printer, a laptop receive such addresses from a home or office router, and go outside already under one shared white address of the provider. With some providers the customer does not get a separate white address at all: their equipment sits behind CGNAT, one more layer of address translation already on the provider side, not on the home router.
Ranges of gray addresses
Which addresses count as gray is defined not by the provider but by the standard: three ranges are reserved for local use and are never routed directly on the internet.
| Range | Mask | Where it is usually found |
|---|---|---|
| 10.0.0.0-10.255.255.255 | /8 | Corporate networks, clouds |
| 172.16.0.0-172.31.255.255 | /12 | Docker, virtualization |
| 192.168.0.0-192.168.255.255 | /16 | Home routers |
Why the address starts with 192.168
Home routers almost always pick the 192.168.0.0/16 range by default — it is set in the factory configuration of most vendors. From it the router usually takes a smaller subnet, for example 192.168.1.0/24 or 192.168.0.0/24, and hands out addresses like 192.168.1.2, 192.168.1.3, and so on to devices. How such subnets and masks are built is covered in the article about CIDR and subnets, and the basic addressing concepts are in the piece about IPv4 addresses.
How a gray address turns into a white one: the role of NAT
The mechanism that links gray addresses inside a network to one white address outside is called NAT (network address translation). It is described in detail in a separate article about NAT; here the general structure matters: the router replaces the address and port of an outgoing packet with its own white address and remembers the mapping to return the reply to the right device.
Laptop (192.168.1.5:40000) --> Router --> Internet (203.0.113.10:40000)
Router keeps the mapping: 203.0.113.10:40000 <-> 192.168.1.5:40000
The reply from the server arrives at 203.0.113.10:40000 and is translated back to 192.168.1.5:40000When you actually need a white IP address
For ordinary browsing a gray address is enough: NAT on the router handles it transparently. A white address is needed when a device must be reached directly from the outside — a mail server, a VDS with a website, a VPN gateway, remote-access video surveillance, or a game server. A gray address on such a server would need extra port-forwarding setup, while a rented VDS usually gets a white address right away.
What to do: how to find out which address you have
You can check your address type in a few steps without any extra equipment.
- Look at the local interface address with the ip addr command or in the operating system network settings.
- Compare it with the ranges table above: falling inside 10.0.0.0/8, 172.16.0.0/12, or 192.168.0.0/16 means a gray address.
- Open any external IP-detection service and compare the shown address with the local one.
- If the addresses match, you have a white address directly; if they differ, NAT stands between you and the internet.
Frequently asked questions
Can I turn a gray address into a white one myself?
No, the address type is assigned by the provider or the network administrator. You can request a dedicated white IP from the provider as a separate service, but turning a private range into a public one on your own side is impossible — internet routing simply will not carry it through.
Why do two devices on different networks share the same gray address 192.168.1.5?
Gray addresses are unique only inside their own local network. Since such networks are not visible to each other directly from the internet, repeating addresses in different homes or offices does not create a conflict: each router works with its own isolated range.
Does a gray address affect internet speed?
NAT itself barely slows down a connection on modern hardware — the translation takes microseconds. Noticeable speed is affected much more by the provider plan, Wi-Fi quality, and router load, rather than by the mere fact of having a gray address.