Why We Don’t Use Hubs Anymore
Hubs might appear to be Layer 2 (Data Link) devices, and I wouldn't blame you if you thought of them as such; however, hubs are actually Layer 1 (Physical) devices. Hubs are, in a sense, "dumb." They are unintelligent devices that simply provide connectivity to several devices. A long time ago, we used hubs as ...
Making DNS Queries and Zone Transfers
Making A DNS QueryDNS is the Domain Name System and its primary purpose is name resolution. Computers rely on the DNS name space to resolve human-readable host names, such as http://www.microsoft.com, into machine-readable addresses, like 23.217.198.68. This really saves us the time from having to remember all the IP addresses of the Web servers that ...
Network Interface Cards (NICs)
How does your computer or mobile device connect to the network in your home or your company's internal network? How are your devices able to transmit, receive, and process information from the Internet? The magic lies in a small card called a Network Interface Card (NIC) built-in to your device. You might also hear them ...
Understanding and Identifying Logical Ports
Identifying Logical Ports There are two types of ports: physical and logical ports. Physical ports are the RJ-45 female jacks that are attached to a switch, router, firewall, server, patch panel, or Ethernet outlet. I've provided some examples below. The ports I'm talking about, however, are logical ports. Understanding Logical Ports In computer science, a ...
How Does DNS Work?
Domain Name System (DNS)When you type in a human-readable Web site name into the URL bar, such as "www.google.com," your Web browser doesn't understand what this means. It needs the machine-readable IP address of the nearest Google Web server to resolve this issue. In comes DNS to the rescue. All of your favorite Web sites ...
The Cybersecurity Man 