Every time you open a web page, something quietly carries that request out to the world and back: an internet service provider (ISP). These are the companies that connect people and organizations to the global internet backbone. Without them, no site loads and no story reaches its readers. This guide explains who ISPs are, what they actually do, and how they fit into Turkey's legal framework.
Related reading: Internet and networking basics · What is an IP address? · What is a static IP?
What Is an Internet Service Provider?
An internet service provider is a company that gives its subscribers access to the internet. It is almost always shortened to ISP. An ISP links its own network to larger networks and opens a path for the data leaving your device to reach a server anywhere in the world.
Every request you send hits your provider's network first, and the provider forwards it along the best available path to its destination. In other words, the ISP is the gateway between you and the rest of the internet. Without that gateway, your device is limited to your local network.
Beyond access, many ISPs bundle extra services: assigning an IP address that maps your connection on the network, DNS resolution, email mailboxes, and sometimes hosting or business connectivity.
What Does an ISP Actually Do?
An ISP's job does not fit into a single sentence; it runs several core functions at once:
- Last-mile connection: Brings a physical line (fiber, copper, cable) or a wireless link to the subscriber's home or office.
- IP address assignment: Gives each subscriber an IP address that identifies them on the network; it can be dynamic or static.
- Routing and transport: Forwards data packets across its own network and neighboring networks toward the destination.
- DNS resolution: Operates name servers that translate domain names into IP addresses.
- Add-on services: May package email, hosting, business VPN, static IP, and technical support.
Types of ISP: A Tiered Structure
The internet is a network of networks, made up of many independent networks linked together. Providers are commonly grouped into three tiers based on their position in that structure. This is an industry convention rather than an official rule.
| Tier | Role | Relationship with other networks |
|---|---|---|
| Tier 1 | Global backbone carrier | Peers with other large networks without paying for transit |
| Tier 2 | Regional/national carrier | Both peers and buys transit from higher tiers |
| Tier 3 | End-user access provider | Mainly buys transit from higher tiers |
The relationship between these tiers runs on two core ideas: peering, where two networks exchange traffic directly and often for free, and transit, where a network pays another for reach to the rest of the internet. How efficient your provider feels depends partly on how well it arranges these connections.
How Do They Connect? Access Technologies
The last mile that links a subscriber to the ISP's network can be built with different technologies. Which one is used depends on the local infrastructure and geography:
- DSL (ADSL/VDSL): Carries data over existing copper phone lines; widespread, though speed drops with distance.
- Fiber (FTTH/FTTB): Uses glass strands carrying light for high capacity, reaching the home or the building.
- Cable: Delivers internet over television cable infrastructure.
- Mobile (4G/5G): Provides wireless access through cellular base stations.
- Satellite and fixed wireless: Serve areas that wired infrastructure does not reach.
ISPs and IP Addresses
When you connect to an ISP, it assigns you an IP address from its own pool. For residential subscribers this is usually a dynamic address that changes from time to time. For running a server, remote access, or anything that needs a fixed identity, you can request a static IP from the provider. Anyone concerned with server security will also meet this layer through open port scanning.
ISPs in Turkey and the Legal Framework
In Turkey, companies offering electronic communications services are authorized by the regulator, the Information and Communication Technologies Authority (BTK). The main framework for internet access obligations is set by Law No. 5651 (on the Regulation of Publications on the Internet and Combating Crimes Committed through Such Publications).
Law No. 5651 legally defines ISPs as "access providers". The obligations of an access provider are distinct from those of a "hosting provider" that stores the content itself. We cover how blocking decisions are applied in how website access blocking works, and for public-sector online systems see what are government information systems.
What to Look for When Choosing an ISP
When comparing providers, the headline download speed in an ad can be misleading on its own. The factors that shape day-to-day experience are usually the ones talked about less. Weigh these criteria together:
- Technology and capacity: Ask which of fiber, DSL, or cable is available at your address and the committed speed range.
- Stability: Downtime and latency (ping) matter more than raw speed for most tasks.
- IP options: Check whether static and additional IPs are offered if you need them.
- Support: Reachability and resolution time during outages are important.
- Contract terms: Read the commitment period, fair-use policy, and extra fees up front.
Is an ISP the Same as Hosting?
They are often confused, but they are different services. An ISP connects you to the internet; a hosting provider publishes your site on it. Keeping a news site running needs both: visitors reach the internet through their own ISPs, while the site's files live on a hosting server. Even when the same company offers both, they are technically separate layers governed by different contracts. Hosting comes in different flavors; offshore hosting, for example, is one of them.