How a Web Server Serve Clients

The Web Servers serve the contents to the clients using Hyper Text Transfer Protocol. The process is explained as below.

1. The end user opens the browser in client machine and enters the desired URL (normally a Fully Qualified Domain Name (FQDN)).

2. The client computer sends the request to the Domain Name Server (DNS server) to resolve the Fully Qualified Domain Name (FQDN) to an IP address. Domain names are created for humans to remember the names easily. Computers communicate with each other using IP Addresses. To start communicating with the Web Server, the Fully Qualified Domain Name (FQDN) of the web server must be resolved to an IP address.

3. The DNS server checks its own records to find a mapping for the Fully Qualified Domain Name (FQDN) to an IP address. If it is unable to resolve itself, it will query another DNS server until it finds a record for the requested Fully Qualified Domain Name (FQDN).

4. The DNS server responds to the original Fully Qualified Domain Name (FQDN) resolution request with the IP address of the web site.

5. The client checks whether the IP address of the web site is in local network. If it cannot find the web site in local network, it uses Address Resolution Protocol (ARP) to locate the hardware address of the router (gateway) that forwards the network traffic to reach the remote network.

6. The client then sends an HTTP GET request to the Web site.

7. After receiving the HTTP request, the web server checks to see if the requesting user has the proper permissions to access the file. If so, the server sends back the requested document.