IP targeting
IP addresses are a central network signal used for determining a user location. When transferring data via HTTP (hypertext transfer protocol), every internet user sends a return internet address. This is either the router’s IPv4 address or an IPv6 address unique to the device. IP addresses are used in order to give each device a distinct address, making them reachable. When accessing a web page, a user sends an HTTP request to the IP address of the responsible web server. A sender address is then automatically provided. The responding web server can then identify the sender of the request and subsequently return the requested data package.
Due to the shortage of IPv4 addresses, routers and client devices are usually not available as static addresses, unlike web servers. Instead, the IPs of internet service providers (ISP) are assigned dynamically. Generally, IP addresses with private internet connections change roughly every 24 hours. It’s then possibly to ascertain a rough estimation of the user’s location based on their IP. This is due to the procedure of awarding IP addresses under the auspices of the IANA (Internet Assigned Numbers Authority), which is a department of ICANN (Internet Corporation for Assigned Names and Numbers). IANA is responsible for allocating IP address ranges to so-called RIRs (regional internet registries). Globally, there are currently five RIRs with different regional responsibilities:
- Réseaux IP Européens Network Coordination Centre (RIPE NCC): responsible for Europe, the Middle East, and Central Asia.
- American Registry for Internet Numbers (ARIN): responsible for the USA, Canada, Bermuda, the Bahamas, and parts of the Caribbean.
- Asia-Pacific Network Information Centre (APNIC): responsible for Asia and the Pacific region.
- Latin American and Caribbean Internet Addresses Registry (LACNIC): responsible for Latin America and parts of the Caribbean.
- African Network Information Centre (AfriNIC): Responsible for Africa.
The five RIRs divide the address areas provided to them into smaller regions and pass them on to local internet authorities (LIR). These are usually internet service providers (ISP), which deal with end-user business. Every ISP has a fixed pool of addresses assigned dynamically or statically to customer routers or terminals. Based on the IP, topological information about the hierarchal structure of the address system and the assignment of subnetworks can thus be read out. This allows website owners to identify the ISP from which the IP was assigned. Its location and area of influence can then be used to draw conclusions about the user’s approximate location. However, the precise address of a customer connection can’t be used in the context of geotracking, as it is subject to data protection and is only known to the ISP.
But especially in the case of large internet service providers, establishing a location based on information provided by the IP is insufficient for geotargeting measures. That’s why many service providers have specialized in the area of determining additional information in order to define an IP address more precisely. Website owners can then pay to access this information, which is generally available in continually updated databases.
In order to define the geolocation of an IP address as precisely as possible, website operators use localization strategies that are based on network measurements and are synchronized with latency periods. Other approaches rely on BGP routing tables, address prefixes, and the Whois database in order to organize IP addresses into clusters. There are also IP databases built by user information given voluntarily for online games. Despite these efforts, IP-based geolocation can only deliver approximate results at the very best. Website operators who require more reliable data should, therefore, use the location sharing option in the web browser.