Network

nslookup

nslookup: Here’s how the useful DNS check works

Those who want to access computer systems and applications in networks need host (or rather, domain) names. As long as the Domain Name System, which is responsible for the name conversions, is functioning normally, users remain unaware that machine-readable IP addresses are hidden behind these names. However, if complications with the DNS and the involved name servers arise, they can be quickly...

Set up your own Raspberry Pi mail server

Raspberry Pi mail server: using Raspberry Pi to manage e-mails

Why use e-mail servers from commercial e-mails service providers when you can just set up your own? You can create a private server easily and affordably with a small computer known as Raspberry Pi. Having your own e-mail server, however, requires a certain amount of work and also has its disadvantages. You can find out more about how to set up your personal Raspberry Pi mail server in this...

What does ‘502 bad gateway’ mean?: Explanation and solution

Error 502 Bad Gateway: Where’s the problem?

HTTP status codes emerge when something isn’t running properly on the internet. In this respect, the 502 Bad Gateway error is no exception. But this familiar error message can be particularly tricky: It’s not actually clear where the source of the problem lies. In the chain of gateways along which internet requests run, the error could occur at a number of different points. This article explains...

Fog computing

Fog computing: decentralized approach for IoT clouds

Traditionally, cloud solutions are designed for central data processing. IoT devices generate data, send it to a central computing platform in the cloud, and await a response. However, with large-scale cloud architectures, such a system inevitably leads to bandwidth problems. For future projects such as connected cities and smart manufacturing, classic cloud computing is a hindrance to growth. The...

How to install an Apache web server

Installing and configuring an Apache web server

The Apache http server is the standard web server for providing HTTP documents on the internet. But did you know it’s also possible to install an apache web server locally on your Windows PC? This is a great method of testing out web pages and checking scripts. To get started, all you need is the free software package and a few minutes.

Private Cloud

What is a private cloud? More control and security for your business

Should data and processes be handled in a private or public cloud? If a company wants to use cloud computing, they first need to choose one of the many providers available. Using the personalized services offered by a private cloud, companies can address a wide range of business related and operational challenges. Separating operations also makes a private cloud more secure than a public cloud.

Man-in-the-middle attack: an overview of attack patterns

Man-in-the-middle attack: attack patterns and countermeasures

A man-in-the-middle attack is a deceitful espionage attack which aims to listen, record, or manipulate sensitive data being sent between unsuspecting internet users. To do this, hackers rely on methods that enable them to position themselves, unnoticed, between two or more computers communicating with one another. We introduce you to some well-known attack patterns and countermeasures that can be...

CIDR: Classless Inter Domain Routing

CIDR: what is classless inter-domain routing?

The internet – just like other large networks – must be precisely subdivided. The network classes, used until the 1990s and not yet completely gone from the scene, were far too inflexible for the requirements of the digital world. CIDR can help: With classless inter-domain routing, it’s possible to create effective subnets and routes. We explain how this works.

Ethernet

What is Ethernet (IEEE 802.3)?

In the beginning, there was ARPANET and ALOHAnet. Then Ethernet followed as a groundbreaking innovation for local networks. Ethernet enabled collision-free interconnection of multiple devices via a common bus. For the first time, data packages could efficiently be exchanged between individual devices. Today, the technology is extensively used in the standard IEEE 802.3. With fiber optic cables,...

The OSI model: a reference for standards and protocols

What’s the OSI model?

Those working with network technology are bound to encounter the ISO-OSI model sooner or later. This system subdivides communication between computer systems into seven different layers. Each of these layers is assigned a certain task. With the help of this layer model, subareas of abstract processes are able to be descriptively explained.