Always be up to date with our server status notification!

Some of you have probably clicked on the link “Server Status” on our website contabo.com already and were forwarded to our status website. In the very rare case of irregular issues occurring in one of our data centers, we inform you about it on this website.

Recently we have revised our status site and added more features. By now, we provide information about all scheduled, ongoing and recently completed maintenances of server systems in our datacenter. Not worth mentioning that customers affected by such a maintenance are also informed by us via e-mail prior to this. These maintenances cannot be avoided altogether – after all, some hardware components are subject to attrition and have to be replaced at the appropriate time. Thanks to our transparent status website, you always know about the server systems which are currently being maintained by our technicians.

A click is worthwhile: http://contabo-status.com/

Posted by: Markus | Tagged as: , , , , No Comments

Full Monitoring

With the Full Monitoring upgrade Contabo offers a tool to monitor the status as well as the state of services.

Why should I monitor my server?

With a monitoring system you are able to detect offline servers or services immediately. With this tool you are able to minimize a service downtime.

A server administrator is not always online to monitor the server 24/7 (in the night or on vacation). In case of a defect the server administrator needs to be informed immediately.

How does the monitoring system look like?

It does not matter if your server is a VPS or a dedicated server, the construction is the same. The most important information is already described in the first line: Is the server online or offline.

Below you can find the state of the services you have chosen to monitor. You can decide for each service how you want to get informed if the service is down. We support notifications via e-mail and text messages (SMS).

With the menu item "Add Services" we added an easy option to add monitoring for a new service. You only have to choose the protocol type (TCP/UDP) and the port the service is listening to.


In the picture below you can see a simple monitoring system. We check if the services on port 80 (http) and 443 (https) are running. Additionally, we monitor a custom SSH port on 60500.


Dedicated Server

Similar to the VPS you can check, add and delete the monitored services. The only difference is that you can directly see the data traffic of your server.


Posted by: Matthias | Tagged as: , , , , , 2 Comments

No summer break at Contabo: Our new VPS plans are unbeatable!

Summer break? Not at Contabo! We have worked extremely hard and updated our entire VPS portfolio for you.
The result? Massive performance boosts combined with price reductions.

The VPS of our 100% SSD series especially benefit from this extensive overhaul. In the host systems of these VPS, we have built in only the latest and fastest Solid State Drives (SSDs) and completely abandoned traditional hard-disks. As a result, the I/O performance of your virtual server is enhanced multiple times. You get the maximum read-write rates – without compromise.
Each aspect of the 100% SSD series VPS has been improved. The new offers thus have more CPU cores, more RAM and more SSD space than before. On top of this, the monthly prices for these VPS have been reduced - really, what more could one ask for? Get your new 100% SSD VPS today!

An overview of the Contabo VPS series "100% SSD":

4 CPU Cores
12 GB RAM (guaranteed)
300 GB SSD disk space
100 Mbit/s switch port
Unlimited Traffic
1 Snapshot
No Setup fee
Rebate depending on the minimum contract period
Only 8.99 EUR / month!

6 CPU Cores
24 GB RAM (guaranteed)
600 GB SSD disk space
100 Mbit/s switch port
Unlimited Traffic
2 Snapshots
No Setup fee
Rebate depending on the minimum contract period
Only 14.99 EUR / month!

10 CPU Cores
50 GB RAM (guaranteed)
1200 GB SSD disk space
1 Gbit/s switch port
Unlimited Traffic
4 Snapshots
No Setup fee
Rebate depending on the minimum contract period
Only 26.99 EUR / month!

Those of you who know us already will not be surprised: We did not stop at this point! The HDD + SSD boost offers have been improved as well: The price of all HDD + SSD boost VPS have been reduced significantly. With a VPS from this series, you will receive an incredibly attractive offer!

An overview of the Contabo VPS series "HDD + SSD-Boost":

2 CPU Cores
6 GB RAM (guaranteed)
500 GB HDD
SSD boost
100 Mbit/s switch port
Unlimited Traffic
No Setup fee
Rebate depending on the minimum contract period
Only 6.99 EUR / month!

4 CPU Cores
14 GB RAM (guaranteed)
1000 GB HDD
SSD boost
100 Mbit/s switch port
Unlimited Traffic
No Setup fee
Rebate depending on the minimum contract period
only 11.99 EUR / month!

6 CPU Cores
30 GB RAM (guaranteed)
2000 GB HDD
SSD boost
1000 Mbit/s switch port
Unlimited Traffic
No Setup fee
Rebate depending on the minimum contract period
Only 19.99 EUR / month!

 Highspeed-support, high-end systems, lowest prices:

Posted by: Markus | Tagged as: , , , , , , 3 Comments

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 "yourdomain.com". It has to replaced with your own one, whenever it appears.

DKIM in cPanel

After you logged into your cPanel account, please search for "Authentication" in the search bar. The matching tool will now get shown in the e-mail section. After opening it, you might see that DKIM has not been activated so far. In this case, please click on the button "Activate". The notification should now look like this, possibly with an error message:


If you have your own server with cPanel and you are using it as a name serrver, the configuration of DKIM might be finished already. In this case, the notification will look like in this picture.

If there is, as already mentioned, an error shown, you will have to translate the raw DKIM record into the final record with the correct syntax and insert it into your DNS zone manually. So please mark and copy the whole raw DKIM record. cPanel offers the code in a form we cannot use directly.  Before we can use it, we have to remove all wrong special characters. For this purpose, we can use Notepad, which is available in every basic Windows installation.

 Please insert the string into the editor:

editor raw

The following has to be removed: everything that stands before "v=DKIM1".  Also all the double quotation marks before,  in the middle or at the end of the key. Furthermore, we have to delete the \ in front of the last ";". Please check that there are no line breaks. Now we have to analyse the part after: "p=". In this part, all whitespaces have to be removed. If you had to remove a " in the middle of the key, there will be such a white space right afterwards. If there are none of the mentioned special characters, it is absolutely okay. The result should look like this:

DKIM fin

Now you have to create a TXT record on your DNS server in the DNS zone for the subdomain "default._domainkey.yourdomain.com". The character string created in the previous step, beginning with: "v=DKIM1...", has to be put into the data part of the record. "your domain.com" has to be replaced with your own domain. If you are using our Contabo nameservers for your domain, please log into the Customer Control Panel, navigate to: DNS Zone Management and edit your domain. Please fill in the fields below "create a new entry" like in the following example:


When you now reload the tool "Authentication" in cPanel with the key F5 on your keyboard, the following should be shown:


If you can see the same message, DKIM has been activated successfully.

If there is still an error shown, you should recheck all the points so far. Are you using the nameservers from Contabo or different ones? Did you change the raw DKIM record correctly?  If you have any questions, you can ask our support. We are reachable over the e-mail address support@contabo.com. It would be a pleasure to help you in this matter.

DomainKeys in Plesk

Please search in the search bar for: "Mail Server settings" and open the tool. At the point : "DomainKeys spam protection", please check the Box "Allow signing outgoing mail". Afterwards, you have to change to the "Mail Settings" of your domain and activate "Use DomainKeys spam protection system to sign outgoing email messages " there, like in the following screenshot:


Then you can open the "DNS Settings" for the affected Domain. An additional TXT entry for the subdomain: "default._domainkey.yourdomain.com" should have appeared.


If it is missing, please repeat all the steps so far, but firstly delete the tick at "Allow signing outgoing mail" in the Mail Server Settings and set it again after saving. If you are using your Plesk as nameserver, the configuration should be finished now. You should now test the configuration. More about this step in the later point: How to test DomainKeys and DKIM.

If you are using other nameservers for your domain, for example the ones provided by Contabo, you have to copy the data part completely and add an identical record in the zone there. To do so, please log into the Customer Control Panel of Contabo, go to the DNS Zone Management and edit the Domain. Please add, like in the following example, a TXT record for the subdomain "default._domainkey.yourdomain.com" with the data part generated by Plesk.


As you can see in the picture, a second record has to be added. This one defines the policy, that every e-mail has to have a DomainKeys signature. Please add the subdomain "_domainkes.yourdomain.com" with the TXT record: "o=-". With this last step, the configuration of DomainKeys has been finished. To ensure that everything is working perfectly, you should do a test now!

 How to test DomainKeys and DKIM

A good way to test a DKIM or DomainKey configuration, is the DKIMValidator.

After opening the site, you can see a randomly generated e-mail address. Please write an e-mail from your server to this address and, after a few seconds of waiting, open the analysis report with the button "view results". With Strg + F, you can search the site, which gives you a lot information. To check if DomainKeys and DKIM are working, search for: "result =". If it reads "pass", everything is working fine. If there is a "fail" you should start a search for the cause. If you are stuck at some point, you can contact us anytime under the e-mail address support@contabo.com. Our team of experts will stand by your side to get it working!

Posted by: Johannes | Tagged as: , , , , , , , No Comments

Changing the partition layout of your VPS after installation

Sometimes, it is necessary to change your partition layout in order to create new partitions or extend an existing partition, for example after a VPS upgrade.

This tutorial shows how to easily change your partition layout on your VPS.

Please be advised to perform a backup of all important data before proceeding ! Changes to the partition table always bear the risk of complete data loss.


Step 1:

Boot your VPS into the rescue-system, this can be done within your customer control panel.

You will need to connect through VNC.

After you have established a connection login as "root".

Step 2:

To perform changes on the partition easily we are going to use gparted.

If you want to boot your system straight up into your regular OS after repartitioning, you should execute "exitrescue" now on the commandline before proceeding.

To start the GUI type "startx" within your VNC console and wait a few seconds until the graphical interface appears.

On the upper left side you will see "Applications", open it and select "Run Program".
Now type "gparted" within the application finder and the app should start immediately.












Step 3:

You should find an overview of all existing partitions on your hard disk drive.
In case there is no unused space left,  we need to shrink one existing partition first, otherwise we will not be able to create a new one.

After a right click on the corresponding partition and choosing "Resize/Move", the partition can be either shrunk or extended.

Please note that LVM partitions (which are used with CentOS by default) cannot be shrunk!


In case you only wanted to extend your existing partition, please proceed with step 5.

Step 4:

Creating new partitions on the recently freed up/already free storage.

Perform a right click on the unallocated space and select "new" to create a new partition.

In this case I did it twice to create two additional partitions.


Step 5:

So far, no actual changes have been made on your hard drive. If you want to restart the partitioning just rerun the gparted tool.

To write the changes to the HDD hit the green tick symbol.
After hitting the tick, a warning will appear saying that you can lose all data - you should have a backup, so no worries.




The application should start performing several tasks, just wait until it has finished.

Depending on the size of the partition and the data stored on it, this will take its time.




Step 6:

You are done, just boot up your VPS into the regular OS  and check if everything is as expected:

root@contabo-test:~# fdisk -l



Step 1:

Connect to your server using RDP.

Step 2:

Open the "Disk Management", this can be done with a right click on the Windows Icon on the lower left side.
You could also start it by opening the "run" prompt, which can be done  via "Start" -> "Execute" -> "diskmgmt.msc", alternately the "Execute" dialogue can be opened by hitting "Windows-Logo-Key +R"

Step 3:

After the Windows "Disk Management" utility was started you will see an overview of all installed harddrives.
On a VPS you will usually have one drive, on a dedicated Server you will probably have more than one sparse disk.
Search for the disk you want to repartition and perform a right click on the partition you want to resize.

You can shrink and also extend a Volume, sometimes when upgrading your VPS to a bigger plan you can either create a second partition or just extend the existing partition.

For now we want to shrink the existing partition, so we hit "Shrink Volume".

Step 4:

After some time passed you will see a popup, just fill out the field with the amount of space you want to free up and hit "shrink".


After shrinking you will have unallocated space, now you are ready to create a new partition, e.g. a FAT32 filesystem etc.


Posted by: Gianni-Donato | Tagged as: , , , , , , , , No Comments

How can I prevent my e-mails getting marked as spam?

You have your own e-mail server, but your e-mails are landing in the spam folder or do not even arrive? This can have several reasons. This tutorial will show you the most important tricks and often overseen configuration mistakes. If you have a webspace package, you will only need the point SPF of this tutorial. In this tutorial we will often use the fictional domain mail.yourdomain.com and the IP address Please replace them with your own ones when you are doing the tests or configuration.

SMTP banner

The SMTP banner is the label of your e-mail server. When it connects to a different e-mail server, it is introducing itself with it. If you have a server from us, it will, at the beginning, answer with something like this:


A lot of e-mail providers will not accept such a label and send your e-mail directly into the spam folder. So it is better to choose a less generic one like:


Please notice, that is has to  be a fully qualified domain name ( FQDN) . That means there has to stand a subdomain like "mail" in front of yourdomain.com. You can request the current SMTP banner by connecting to your server with Telnet over port 25. You can do this in Windows by entering the following command into the Windows  command prompt:

telnet 25

Please use your own server IP here. If you are using Windows, you will have to activate Telnet first! (Start --> Control Panel --> Programs and Features --> Turn Windows features on or off--> wait a moment, then check the Telnet Client check box and finish with clicking on OK)
The output might look like this:

220 m1234.contabo.net ESMTP Postfix (Debian/GNU)

"m1234.contabo.net" is the important information in this line. You can leave the session by entering "quit" and hitting enter. In cPanel and Plesk, the mailserver's name in the SMTP banner is equal to the hostname. So you can alter it by changing the hostname in the administration panel.
If you are using Plesk on a Windows server, it is not so easy to change the banner. Please log into your server over RDP, open the tool "MailEnable" and go to: MailEnable Management --> Servers --> localhost --> Connectors. Then choose in the opening list SMTP, click on it with you right mouse key and open "Properties". In the opening window, there are four fields you have to fill in:

Local Domain Name

Here you have to enter you main domain. For example: yourdomain.com.

Default mail domain name

This is your e-mail server name in the SMTP banner. For example: mail.yourdomain.com

DNS Addresses

Here you have to enter the DNS servers. If you have your server in one of our datacenters, the following addresses would work perfectly:

for Nuremberg:

for Munich:

Notification email address

Please enter an existing e-mail address.

If you are using Postfix instead of an administration panel, you can change the SMTP banner by using this command in the terminal:

postconf -e "myhostname = mail.yourdomain.com" && postfix reload

Please replace "mail.yourdomain.com" with the new domain name of the e-mail server.


The PTR, or also called reverse DNS record, is the counterpart of the A-record in a DNS zone.


mail.yourdomain.com -->

PTR: --> mail.yourdomain.com

Most e-mail servers only accept an e-mail, if the PTR is exactly the same as the name of the mailserver in the SMTP-Banner! If you have for example the following SMTP-Banner:

220 mail.yourdomain.com  ESMTP Postfix (Debian/GNU)

You have to change your PTR like in the upper example, what can be done easily in the Customer Control Panel. Please notice, that you have to change the PTR of the IPv6 address too, if you are using IPv6 additionally to IPv4. It will not harm to do it anyway, if you are not sure.


With the SPF record you determine that it is only allowed to send e-mails from specific IP addresses. Many e-mail servers are considering e-mails from domains without SPF record as spam. You can add an SPF record in the Customer Control Panel with the DNS Zone Management. The following one should work in most cases:

86400 in TXT "v=spf1 +a +mx ~all"

It will allow the IP named in the A-record and the one of the mailserver, named in the MX-record.

If you use one of our webspace packages, please use the following one:

86400 in TXT "v=spf1 +a +mx +a:mail-relay.contabo.net ~all"

If you have a special configuration, you can use a tool like this to generate an individual SPF:



We always do test our IP addresses, before we give them to our customers. But it is not impossible, that your IP is currently on a blacklist. This will cause your sending attempts to fail despite all your tries to achieve a perfect configuration. If you assume that your IP might be on such a list, you can test for the most important ones on this site:

MX-Toolbox Blacklist Check

Please enter the IP address of your server and wait some seconds for the test! If the IP is listed somewhere (marked in red), you should contact the owners of this list. They will offer a removal form on their home page. The IP should be removed in a few days. Some e-mail providers have their own lists, that can not be reviewed so easily. They normally will send you a bounce e-mail to signal, that the sending attempt failed, with the reason included in it. If they mention an internal blacklist, you can find below some links to the removal forms of such providers:


If you have problems getting your IP removed from such a list, please write an e-mail with the error message and the IP to support@contabo.com. We will help you solving this problem.

Additional points

If you have paid attention to all the points so far, and your e-mails have still problems with reaching the recipient or are landing in the spam folder, it is time to look for the reason in close detail. Have you got a reply when the e-mail was not accepted? Read this e-mail carefully. Often there stands the reason for this behaviour! If you have found such a message, but it does not help you, you are free to sent it with the complete header to our support. Our team of experts at support@contabo.com has a lot of experience with solving such problems!

If the e-mail is arriving but landing in spam, the header of the received e-mail will often contain useful hints. Especially Google makes it easy for the owners of small e-mail servers and often adds a link to its e-mail guidelines. Therefore, it might be useful to send a test e-mail to a Gmail address too, for a further analysis!

Please also take a look on the free MX-Toolbox SMTP Check. Here you have to enter the domain of your e-mail address. The site will test your configuration for common problems!

If nothing helped

If you have worked through the whole tutorial, and there are still problems with sending e-mails, or you need help at some point, you can contact our support. We are there for you everyday from 8:00 to 23:00 (German time) at support@contabo.com.


Limited offer: 4 x 4 TB disk space via RAID 10 at only 59.99 EUR / month

We have reduced the price for one of our most popular server upgrades, the 4 x 4 TB HDD RAID 10 bundle! Instead of 79.99 Euro per month, it is now available at a stunning 59.99 Euro per month!

Important for you to know: It pays to be quick as this special price is available for only a short time, as long as stocks last!

If you require a huge amount of disk space for your server at Contabo, combined with an outstanding performance and an extremely high reliability, our RAID bundle with four 4 TB HDDs is the best solution for you. This upgrade features four extremely reliable HDDs by HGST. These disks are constructed explicitly for 24/7 usage and have a capacity of 4000 GB per HDD. The HDDs are connected via an Adaptec or LSI RAID controller as a hardware RAID 10. This means that even in the highly unlikely case of a disk failure, your data will be safe. At the same time, you profit from clearly better I/O.

As you know such a combination of powerful state-of-the-art hardware is generally not cheap. That is why this upgrade did cost 79.99 EUR per month, up to now. Only for a short time, we can offer it at just 59.99 EUR per month - Take advantage of this one-time opportunity and grant your dedicated server at Contabo the 4 TB RAID bundle!

The 4 TB RAID bundle is available for every dedicated server. The bundle can be ordered as an upgrade for existing or new servers.

Interested? Then please take a closer look at our dedicated servers!

Posted by: Markus | Tagged as: , , , , No Comments

How to perform a file system check?

The file system check is is a practical tool if an error occurs in your file system and your server is not booting any more. With this tool you can analyse and repair such errors in your file system. We recommend to backup all your data before you start with this operation, because there could be data loss of your server during the repair process. Please start the file system check in the rescue system.

If you do not know what the rescue system is or how to start it, please click here.


As soon as your server has booted into the rescue system, please use the following command to display all existing partitions.

  • fdisk -l


In this example the system partition is located on /dev/vda1. Normally the system partition is located on /dev/sda1 or /dev/vda1.

Please use the following command to check which file system type is used.

INFORMATION: Please use your actual partition, in our case we have to use /dev/vda1

  • blkid | grep vda1 | awk '{print $3}'


Depending on which file system is used and which partition has to be checked,  you have to use the following commands. This is only a check in advance and your file system will not be repaired.

  • fsck.ext2 -n /dev/vda1 = For the file system ext2
  • fsck.ext3 -n /dev/vda1 = For the file system ext3
  • fsck.ext4 -n /dev/vda1 = For the file system ext4
  • fsck.btrfs -n /dev/vda1 = For the file system btrfs
  • and so on...

In our case we are using the file system ext4, therefore, we have to use the following command. Please use the command with the right file system type for the rest of the following commands.

  • fsck.ext4 -n /dev/vda1


You will get as result the errors of your file system. If you would like to repair scattered errors, so use the following command.

  • fsck.ext4 /dev/vda1


If you think that all errors have to be repaired, please use the following command. This command includes the parameter  -y which answers all queries with  "Yes". It is not necessary to answer them manually.

Important: We recommend to use this command only if you are 100 percent sure.  All queries will be accepted without further notification.

  • fsck.ext4 -y /dev/vda1


Your system should start normally once the file system check has been finished.

If you would like to exit the rescue system and booting from the regular hard drive, please use the following command.

  • exitrescue && reboot

Your server should will start the operating system now.

Additional important information:

If you start a file system check , some files might lose the information about their names and locations in the file system. The file system check deposits these files in a specific directory called lost+found. If there are missing files after you have performed the file system check, you will be able to find the files in this directory in most cases.

Posted by: Mike | Tagged as: , , , , No Comments

What to do if your server is not reachable anymore

If your server should run but is not reachable, the reason might be a routing problem between your internet provider and Contabo and you should follow these instructions:

To make sure it's not an connectivity issue we recommend to create a so called "MTR report".

MTR does nothing else than a traceroute combined with PING.

To create a simple traceroute type the following into your command line:

Open your cmd.exe or your powershell application and type
tracert <your IP>
Linux :
Open a terminal and type
traceroute <your IP>

Starting an MTR is very easy, just get the latest Version here :
On Linux you should be also able to install it from your repository:
apt-get update && apt-get install mtr

After installing the necessary package, you can run the application.

Windows: Navigate to the downloaded folder and unzip the file, some directories have been created. Rightclick on the .exe and hit "Run as administrator". Now just type your IP and hit start.


Linux: Open your terminal and enter mtr <your IP>


It's recommended to run the application for at least 10 minutes, this makes sure that enough data is being collected.

Take a screenshot or save the log file, our support will need those information if you plan to contact us.


Posted by: Gianni-Donato | Tagged as: , , , , , , , 1 Comment

Mounting of additional hard drives in Windows

In this tutorial, we are going to mount an additional hard drive in Windows. As you may notice, we will do so in Windows Server 2012, but the procedure is basically the same with Windows Server 2008.

At first, we need to open a menu by right-clicking the Start button:


We must select Disk Management to open the Disk Management service. If Windows identifies a new hard drive, a pop-up menu opens:


For volumes smaller than 2 TB, we choose MBR, for larger disks, we select GPT. As the hard drive in our example only has a capacity of 100 GB, we'll go with MBR here. By clicking OK, the chosen partition table will be written to the hard disk. After that procedure, we will be sent to the main menu of the Disk Management service. Alternatively, one can reach this overview via Control Panel => Computer Management.


As we can see here, our new hard drive is listed as Disk 1. But before we can use it for storing data, we need to partition and format it. Therefore, we right-click the rectangle next to the box which says Disk 1 and choose New Simple Volume.


A wizard opens. It is quite self-explanatory and you can't do anything wrong by using the pre-selected and suggested values. Per default, the wizard uses the whole disk capacity for the new partition and formats it with the file system NTFS, which is recommended for Windows. Of course, you are free to change those settings, but in our example, we go along with them.


The name of our new partition is STORAGE, but of course you can name it as you wish.

Once you went through the wizard, the new hard drive will be ready to use. It will also be visible in the Explorer: