Public IP

What Is a Public IP Address

A public IP address is the “street address” of your internet connection. Using it, external sites and services see you (more precisely, your router/provider), establish connections, apply geolocation and access rules.
Unlike the local (private) IP, which lives inside a home or office network (ranges 10.x.x.x, 172.16–31.x.x, 192.168.x.x) and is not routed to the Internet, the public IP is unique in the global network and is visible from the outside.

Why is it needed:

• Online identification: Websites, games, and cloud services need to know where to send responses.
• Incoming connections: home hosting, remote access, P2P — without a public address (or its equivalent), this is impossible or highly complicated.
• Network policies and geo: content, prices, captchas, and blockages often depend on the public IP and its country/ASN/reputation.

How Public IP Address Works

Appointment by the provider. Your ISP issues a public IP to your router via DHCP/PPPoE/IPoE. Sometimes this is done on the operator’s border equipment, and a “private” transport network (CGNAT) stretches to you. If you want to know more about ISP, what it is and how it works feel free to check our article.

The role of NAT. In a typical home, one public IP “covers” dozens of local devices. The router does NAT: all traffic goes outside from one public IP, and inside the packets are distributed over private IP. This saves addresses and simplifies security, but it interferes with incoming connections “from the street” (port forwarding/UPnP is needed).

Static vs dynamic public IP.

• Dynamic: Changes during reconnection/periodically. Cheaper, suitable for regular surfing/streaming. Cons — inconvenient for hosting and stable firewall rules.
• Static: assigned to you. It is convenient for VPN gateways, servers, remote administration, IP whitelists.

This is usually a paid option. CGNAT stands alone: the operator has a common public address for many subscribers. Plus, IPv4 savings; minus, there are practically no incoming ports, it’s more difficult with games/VPN/P2P.

Historical Background: From IPv4 to IPv6 in Public IPs

IPv4 shortage. There are only ~4.3 billion addresses in IPv4, a significant part is reserved. With the growth of the Internet, the pool of free addresses at regional registrars (RIRs) has dried up, and it has become more difficult for providers to issue unique public IP addresses to each device. Transition solutions: NAT, CGNAT, Denser addressing (CIDR).

The advent of IPv6. IPv6 brought 128-bit addresses — in fact, “there are enough addresses for everyone and for a long time.” Public IPv6 can be assigned directly to devices, reducing the need for NAT, simplifying end-to-end connections, and increasing routing scalability.

How the distribution has changed.

• With IPv6, providers distribute prefixes to clients (for example, /56 or /64), rather than single addresses — the subscriber has “hundreds of networks” for IoT devices at once.
• For IPv4, the trend towards CGNAT and paid static public IP has increased.
• The practice has become hybrid: dual-stack (IPv4+IPv6 at the same time), transitional mechanisms (NAT64/DNS64), and the gradual growth of services available over IPv6 natively.

Bottom line: understanding the difference between public vs private IP, the role of NAT/CGNAT, and the direction of migration to IPv6 helps you set up networks correctly, solve problems with service availability, and choose the appropriate type of address from your provider.

Key Uses of Public IP Address

• Identification on the Internet. The public IP is your “passport” on the network. Every website, game, or online service sees your public IP and uses it to differentiate between users. That is why IP ban or geolocation is possible — the address becomes a digital marker.
• Access to online games, VPN, and hosting. To play multiplayer games, connect to a work VPN, or run your own game server, you need a public IP address. Connections are established through it. Without this, many services simply don’t know where to send packets.
• Connecting servers and services. If you are an administrator or developer, public IP allows you to host a website, database, or remote access. In this case, it works as the address of the “home” on the Internet, where visitors and colleagues come.
• Geolocation and regional restrictions. The public IP defines the country and the city, which means that the content is available. Streaming services, app stores, and even search engines adjust to the region by IP. Sometimes this is useful (local results), and sometimes it creates barriers (regional blockages).

Common Issues and Risks with Public IP

• Provider and tracker surveillance. Your ISP sees all your connections over a public IP, and advertising networks and analytics companies use IP for profiling.
• Blockages and IP blacklists. If your address is included in the spam database or has been noticed in suspicious activity, access to websites or e-mail may be restricted. Therefore, IP blacklist check has become a standard practice for diagnostics.
• Changing the dynamic IP. With a dynamic address, you may suddenly lose access to the service where the old IP was linked, or encounter captchas if the new address had a “bad reputation.”
• Security threats. Public IP makes you visible on the Internet. Hackers can scan address ranges in search of vulnerable devices. If your router or server is incorrectly configured, this is the entry point for an attack.