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What is an IP address?
In order to receive regular mail, the postal service in your country has to know where to deliver your mail. Well, on the internet it works kind of the same way. You either have an IPv4 or an IPv6 address Public vs Private Simply put 😉 a public IP (address) is the...
What is a CDN?
In plain English, a CDN (Content Delivery Network) is a collection of servers spread across different locations around the world. Its purpose is to help deliver digital content, such as web pages, images, videos, and other files, to users in a faster and more...
What is ‘the list of well known port numbers’?
What are port numbers? As we were discussing the OSI model and the difference between TCP and UDP we already learned some of the bits how protocols work on the transport layer. Together with the transport protocol used (these are not limited to TCP and UDP only but...
What is the difference between TCP and UDP?
Let's spell out the acronyms first. TCP stands for Transmission Control Protocol and UDP stands for User Datagram Protocol. In networking we often use the OSI model as a reference to clarify on which layer of the OSI model a protocol is used. We did an article on the...
What is the OSI model?
OSI stands for Open System Interconnection and Its model describes via which steps (called layers) computers take to communicate over a network. The seven layers are from top to bottom: Layer nameFunctionApplication layerHuman interaction with the application and the...
What is FTP?
FTP stands for File Transfer Protocol. As the name implies it's protocol that facilitates the transfer of a file from one client over the network to another client. FTP modes: active versus passive FTP connections can be made using one of these two modes. In active...
What is SSH?
SSH or Secure SHELL is an authentication protocol that support several authentication methods. (Certificate based, username/password) But we have telnet? Remember what I told you about Telnet in this article? Yes indeed, it sends all packets in clear-text over the...
What is telnet?
Telnet is an application (protocol) that can be used to manage devices remotely. So if you want to log in to a router, switches or any other device that has a telnet client installed, you can use telnet. telnet 10.0.0.1 <any specific port/when not specified 23 is...
What is SNMP?
In the world of networking there are a lot of tools and protocols but in the monitoring area SNMP or Simple Network Management Protocol is probably the most widely used. It is old but it is one of those protocols that will stick around forever. What is it used for?...
What is NTP?
This is probably going to be one of the shortest posts I have ever written, about an invaluable protocol for every network. NTP stands for Network Time Protocol and is a protocol, you guessed it, that is responsible for time synchronization in a network. There are...