ISP (Internet Service Provider)

The company you pay your monthly internet bill to is your ISP. They are the gatekeepers that allow you to access the vast ocean of information known as the Internet.

1. What is an ISP?

ISP (Internet Service Provider) refers to a company that provides internet access services to individuals and businesses.

The Analogy: Utility Company

• Internet: Similar to Electricity or Water supply.
• Your Device: An appliance or faucet.
• ISP: The Utility Company that lays the pipes/cables to your house and bills you for usage.

Without an ISP, your computer is like a faucet with no pipes connected—it cannot access the flow of the internet.

2. Key Roles of an ISP

Their most critical roles are assigning IP addresses and providing physical connectivity.

1. Assigning Public IPs: As learned previously, the [Public IP] assigned to your modem comes from your ISP's pool of addresses.
2. Network Connectivity: They physically connect you to the global network via fiber optics, copper wires, or satellite links.
3. DNS Services: They maintain Domain Name System (DNS) servers to translate website names into IP addresses.

3. Types of ISP

• Commercial ISP: Companies like Verizon, Comcast, AT&T (in the US) or KT, SKB (in Korea) that serve homes.
• Hosting ISP: Companies that provide servers and bandwidth for websites (e.g., AWS, hosting firms).

4. [Tip] Who is my ISP?

If you are unsure which ISP creates the network you are currently using: * Visit an internet speed test site (like Fast.com or Speedtest.net); they usually display the ISP name. * Look up your Public IP on a WHOIS service to see the owning organization.