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DomainKeys and DKIM in Plesk and cPanel


DomainKeys and DKIM can help you to increase the reputation of your e-mail server and preventing others to manipulate or fake your e-mails. In this tutorial, we want to show you how you can activate this feature in cPanel and Plesk. Firstly, we have to clarify that Plesk allows you to activate DomainKeys in the web interface and that cPanel is using the newer version called DKIM. Those are both quite similar in many points, but we will use those terms separately. All the images in this tutorial can be shown in a bigger version with all the details, by clicking on them. We will often use the example domain “”. It has to replaced with your own one, whenever it appears.

Ultimate Guide to SSL

Ultimate Guide to SSL (head image)


In the rapidly evolving digital landscape, the need for secure and private communication on the internet has become more crucial than ever. This is where SSL (short for: Secure Sockets Layer) comes into play. SSL is a fundamental technology that ensures encrypted connections between web servers and browsers. This is archived by safeguarding sensitive information like passwords and protecting users from cyber threats. In this comprehensive guide, we will explore the world of SSL, its historical context, and its significance in modern web usage. 

 SSL, first introduced by Netscape in 1994, revolutionized the way data is transmitted over the internet. It provided a secure layer of encryption, making it increasingly difficult for attackers to intercept and decipher sensitive information exchanged between users and websites. Over the years, SSL has evolved into Transport Layer Security (TLS), encompassing newer versions and stronger cryptographic algorithms to enhance security. 

System Rescue CD: First Steps

 sysresccd login

Many of you have already heard about it or even used it once in a while, but most of you have probably not been introduced to it yet: Our rescue system! While hopefully not being needed at all, it provides many possibilities to fix certain problems and to bring the machine back online as soon as possible. When the server is down, every second counts. It is important to know what to do beforehand. Thus, I will provide you with some basic information first:

SRV Records – How do I use them correctly?


Definition of an SRV record

With a Service Resource Record (short: SRV record) you can make services, which are usually available via an IP:PORT combination, reachable using a DNS host name. Important to note regarding SRV record is the fact, that they only work if an application has been specifically programmed to make use of them. Examples for this are TeamSpeak3 or Minecraft. SRV-Records can not be used to point a DNS name to an IP address/port combination for arbitrary use by any application.

Example – Teamspeak:
Usually TeamSpeak is using the protocol UDP over port 9987. If you are running a TeamSpeak instance with the IP every client that wants to connect has to enter the IP:port combination of If you change the port or the server IP, you have to inform everyone about the new combination. With SRV records it is possible to connect to TeamSpeak using a DNS host name like

How to Configure Cloudflare in front of Your Website or Application

How to Configure Cloudflare (head image)

Cloudflare is a content delivery network (CDN) that provides a range of services, including DDoS protection, caching, and website optimization. By configuring Cloudflare in front of your website or application, you can take advantage of these services to improve the performance and security of your site. However, setting up Cloudflare can be a daunting task for those who are unfamiliar with the process. In this article, we will provide a step-by-step guide on how to configure Cloudflare in front of your website or application, so you can start enjoying the benefits of this powerful CDN. Whether you’re a seasoned developer or a beginner, this guide will help you get up and running with Cloudflare in no time. 

Create a Cloudflare Account

The first step in configuring Cloudflare for your website or application is to create an account. Go to the Cloudflare website and click on the “Sign Up” button. You will be prompted to enter your email address and create a password. Now check your email inbox to verify your email address. Once you have completed this step, you will be directed to the Cloudflare dashboard which looks like this: 

Add Your Website to Cloudflare

The next step is to add your website to Cloudflare. To do this, click on the “Add Site” button and enter your website URL: 

Cloudflare will then scan your website to determine its DNS records.  

Choose a Cloudflare Plan

Cloudflare offers a range of plans, from a free plan to more advanced plans that offer additional features. Choose the plan that best suits your needs and click on the “Continue” button. 

In this example we will choose the “Free”-Tier. 

Update Your DNS Settings

Once this is done, Cloudflare will display a list of DNS records for your website. If there are already some entries, verify that these records are correct or delete them and then click on the “Continue” button. 

Now Cloudflare will display new nameservers that you need to update on your domain registrar’s website. This is usually where you purchased your domain name. For Contabo customers this can be done via the Customer Control Panel (CCP) at Your DNS settings can be updated under “DNS Zone Management”. If you want to learn more about DNS Zone Management, check out this article. If you are with some other provider, you will need to log in to your domain registrar’s website and update the nameserver records with the ones provided by Cloudflare.


Verify Your DNS Settings

Once you have updated your DNS settings, go back to the Cloudflare dashboard and click on the “Done, Check Nameservers” button. Cloudflare will then verify that your DNS settings have been updated correctly. This may take some time, so be patient. Cloudflare will send you an email if these DNS settings have been updated. 

Connect your Server with your Domain on Cloudflare

After your DNS settings have been updated, it’s time to connect your server with the Domain you set up at Cloudflare. To do so choose “Websites” in the left menu: 

Now click on your Domain: 

And select “DNS” in the left menu: 

To connect your server with this domain, click on “Add record”: 

  1. Now leave the “Type” on “A”. 
  1. For “Name” enter your Domain (e.g. 
  1. For IPv4 address enter the IPv4 Address of the server you want to connect with your domain (In Contabo this can be found in the Customer Control Panel –> Your Services) 
  1. Now click on “Save” 

In our example it looks like this: 

Now it will again take some time to update your DNS settings. Again: It can take up to 24 hours but will usually be done in a few minutes. 

Enjoy the Benefits of Cloudflare

Congratulations! You have successfully configured Cloudflare in front of your website or application. Cloudflare will now provide a range of services to help improve the performance and security of your site, including DDoS protection, caching, and website optimization.