DNS request, TCP/IP, Firewall, HTTPS/SSL, Load-balancer, Web server, Application server, Database

A DNS query (also known as a DNS request) is a demand for information sent from a user's computer (DNS client) to a DNS server. In most cases a DNS request is sent, to ask for the IP address associated with a domain name. The Internet Protocol (IP) is the address system of the Internet and has the core function of delivering packets of information from a source device to a target device. IP is the primary way in which network connections are made, and it establishes the basis of the Internet. IP does not handle packet ordering or error checking. Such functionality requires another protocol, typically TCP.

The TCP/IP relationship is similar to sending someone a message written on a puzzle through the mail. The message is written down and the puzzle is broken into pieces. Each piece then can travel through a different postal route, some of which take longer than others. When the puzzle pieces arrive after traversing their different paths, the pieces may be out of order. The Internet Protocol makes sure the pieces arrive at their destination address. The TCP protocol can be thought of as the puzzle assembler on the other side who puts the pieces together in the right order, asks for missing pieces to be resent, and lets the sender know the puzzle has been received. TCP maintains the connection with the sender from before the first puzzle piece is sent to after the final piece is sent. Firewalls have existed since the late 1980’s and started out as packet filters, which were networks set up to examine packets, or bytes, transferred between computers. Though packet filtering firewalls are still in use today, firewalls have come a long way as technology has developed throughout the decades.

Gen 1 Virus Generation 1, Late 1980’s, virus attacks on stand-alone PC’s affected all businesses and drove anti-virus products. Gen 2 Networks Generation 2, Mid 1990’s, attacks from the internet affected all business and drove creation of the firewall. Gen 3 Applications Generation 3, Early 2000’s, exploiting vulnerabilities in applications which affected most businesses and drove Intrusion Prevention Systems Products (IPS). Gen 4 Payload Generation 4, Approx. 2010, rise of targeted, unknown, evasive, polymorphic attacks which affected most businesses and drove anti-bot and sandboxing products. Gen 5 Mega Generation 5, Approx. 2017, large scale, multi-vector, mega attacks using advance attack tools and is driving advance threat prevention solutions.

Load balancing refers to efficiently distributing incoming network traffic across a group of backend servers, also known as a server farm or server pool.

Modern high‑traffic websites must serve hundreds of thousands, if not millions, of concurrent requests from users or clients and return the correct text, images, video, or application data, all in a fast and reliable manner. To cost‑effectively scale to meet these high volumes, modern computing best practice generally requires adding more servers.

A load balancer acts as the “traffic cop” sitting in front of your servers and routing client requests across all servers capable of fulfilling those requests in a manner that maximizes speed and capacity utilization and ensures that no one server is overworked, which could degrade performance. If a single server goes down, the load balancer redirects traffic to the remaining online servers. When a new server is added to the server group, the load balancer automatically starts to send requests to it. A web server is software and hardware that uses HTTP (Hypertext Transfer Protocol) and other protocols to respond to client requests made over the World Wide Web. The main job of a web server is to display website content through storing, processing and delivering webpages to users. Besides HTTP, web servers also support SMTP (Simple Mail Transfer Protocol) and FTP (File Transfer Protocol), used for email, file transfer and storage.

Web server hardware is connected to the internet and allows data to be exchanged with other connected devices, while web server software controls how a user accesses hosted files. The web server process is an example of the client/server model. All computers that host websites must have web server software.