How Are IP Addresses Assigned? Understanding Where Your IP Address Comes From

An IP address comes from a four-step chain.

1. IANA manages the global IP address pool.
2. RIR registries receive large blocks for each region.
3. ISP operators, including internet service providers, obtain blocks from their registries.
4. Your network is assigned one IP address, usually on the router.

The result depends on your provider, connection type and location.

For example, a home network receives one from a local provider, whose block came from its regional registry.

What an IP Address Is and Why Every Device Needs One

An IP address is a numeric Internet Protocol label that lets network devices find and talk to each other. IPv4 has four numbers, such as 192.0.2.1. IPv6 uses longer values. On Wi-Fi, a laptop, phone and smart TV are separate devices on one network. Each needs its own IP address to receive the right data. It belongs to an IPv4 network connection, not a person. One person can see a different IP address at home, work, or mobile data. IPv4 scarcity shapes network reuse. Provider policies can often replace that IP address.

How IP Addresses Are Assigned: From IANA to Your Device

IP address assignment cascades in stages from the global pool: IANA allocates regional blocks, then ISPs get blocks assigned before serving each customer network.

IANA and the Regional Internet Registries

IANA holds the global address pool and passes large IPv4 address blocks to five regional internet registries. Each RIR records which network received allocated IPv4 resources and sets rules for local network resources.

• ARIN: North America
• RIPE NCC: Europe, Middle East, Central Asia
• APNIC: Asia-Pacific
• LACNIC: Latin America, Caribbean
• AFRINIC: Africa

A German provider requests an address from RIPE NCC. A Brazilian one asks LACNIC.

How ISPs Get Their Address Blocks

Internet service providers, hosting providers and large organisations request and hold a block from their regional registry, with an ASN, a routing identifier. Each ISP divides that pool among customers. A cable provider can serve thousands of homes. Customers receive an address from the pool. Each address is temporary. IPv4 resources are assigned to networks, not individuals.

How Your Provider Assigns an Address to Your Router

When your router connects, a public IP address is assigned from the ISP pool. It identifies the whole household connection, not each phone or laptop. Inside the local network, private addresses are assigned to connected devices over Wi-Fi or Ethernet. After a router restart, the connection may later receive a different public address from the same provider pool.

Static vs. Dynamic IP Addresses

Most home users get a changing IP address, sacrificing fixed reachability for efficiency. Businesses often pay for static mail server reachability.

Temporary Addresses and DHCP

Routers and ISP servers use Dynamic Host Configuration Protocol (DHCP) to lease an address from a pool. DHCP renews or replaces that address after a limited lease. This reuses limited IPv4 resources and avoids manual setup, but the address may not remain stable. A phone on café Wi-Fi gets one for a session and loses it when leaving. Inside home networks, the router hands private addresses to devices the same way.

Static IP Addresses and When They Are Used

A static IP address remains fixed. It is reserved or manually configured, so the network endpoint does not change. Providers often charge extra because static IPs consume resources.

• Servers and websites need one predictable IP address.
• Remote access: small offices keep the same VPN endpoint.
• Email servers use static endpoints.

Public vs. Private IP Addresses

A public IP address is reachable on the internet. A private IP address is reused inside local networks, using 192.168.x.x, 10.x.x.x, or 172.16–31.x.x. Two neighbours can use 192.168.1.10 on Wi-Fi devices, yet websites see a different public address per network.

How NAT Lets Many Devices Share One Public Address

Network Address Translation (NAT) lets home networks present many devices behind one public IP. The router swaps private addresses for its unique public one and records which device made each request. NAT maps a family laptop, two phones and a console to one online identity. This reuse slowed IPv4 exhaustion. Carrier-grade NAT does this across provider networks, sharing one address among many customers.

What Determines Your IP Address

Your public IP address depends on:

• Provider pool and network type.
• Home, office, or mobile network.
• Provider registration, not street location.
• Static, changing, or NAT network assignment.

Commuting on 5G brings a different address. Check your IP location.

Mobile Networks and Shared Addresses

A mobile provider puts phones behind carrier-grade Network Address Translation. Many devices share a few public IPs, and each connection can change between towers or after reconnecting. Since many real users sit behind one IP address, websites usually treat it as ordinary.

Need a mobile carrier address? OnlineProxy provides mobile proxies on real carrier IPs from 4G and 5G connections, served through modems and SIM routers with real SIM cards. For example, a social media manager can test mobile views or multi-account work over HTTP or SOCKS5 with username and password.

IPv4 Exhaustion and IPv6 Adoption

IPv4 supplied 4.3 billion internet address slots. IPv4 exhaustion at RIRs pushed NAT, trading, and IPv6 adoption. IPv6 adoption adds an IPv6 address alongside a shared IPv4 one.

Why IPv4 Addresses Are Still Important

IPv4 remains essential because much of the internet still uses it. Many websites, apps, and network devices still expect it. An old printer or legacy service may accept only an IPv4 address. ISPs conserve scarce resources with NAT and short leases. Across the internet, dual-stack IPv4 and IPv6 networks will remain normal for years.

IP Address Assignment FAQ

Answers to common assignment questions.

Can two people have the same IP address?

Yes. Households share one public IP address through NAT, while mobile users often share one too. Private addresses repeat safely across separate local networks. They are not globally unique.

What can someone actually do with your IP address?

Geolocation data can infer your rough region and ISP from an IP address. It cannot reveal your street address. Only the provider can link that network record, under legal request, to a customer account.

Can I choose my own IP address?

No. Your public IP address comes from your ISP. You can request a static address, often for a fee, and you can set private addresses inside your own router network.

Key Takeaways: Who Decides Your IP Address

IANA and each RIR distribute internet resources, and ISPs get one IP address assigned to your network. It usually belongs to the network connection, not individual users, while NAT or IPv6 affects how sharing works. Your assigned IP address is often temporary, shared, and largely provider-controlled.