What is an IP address?
A numeric label assigned to every device on a network that uses the Internet Protocol, used to route packets between hosts.
Also known as: IP, Internet Protocol address
An IP address is the postal code of the internet. When your browser asks for stripe.com, DNS resolves the hostname to an IP (something like 34.149.87.45), and routers on the path use that IP to forward packets to Stripe's servers. Every device that talks IP, from your phone to the load balancer in a data center, has at least one address.
IPv4 addresses are 32 bits and written as four dotted decimals (192.168.1.1). The world ran out of unique IPv4 addresses years ago, which is why most home networks share one public IPv4 across every device using NAT. IPv6 addresses are 128 bits, written in hex with colons (2001:db8::1), and are plentiful enough to give every grain of sand on Earth its own.
For crawling and brand-data work, IPs matter for two reasons. Anti-bot systems rate-limit and ban by IP, which is why scrapers rotate through proxy pools. And IP-based geolocation lets servers decide which content (pricing, language, legal banner) to show, so a crawler in us-east-1 sees a different page than one routing through a residential IP in Germany.
In the wild
- A scraper rotating through 1,000 residential IPs to avoid per-IP rate limits
- A CDN routing the same URL to a different edge node based on the requesting IP
- A login system flagging an account when it sees logins from geographically distant IPs in the same hour