Cloud Server: Troubleshooting
Identifying and Fixing Errors in Case of a Server Failure
This article explains how to collect information about your system and possible sources of error when your Cloud Server fails.
If your server is no longer accessible, please first try to exclude possible sources of error step by step in order to identify and eliminate the cause as quickly as possible. Proceed as follows:
Restart and check connection to the server
Perfom arestart of the server.
Depending on the operating system and configuration of the server, this process can take up to 10 minutes.
Check whether you can connect to the server using SSH (Linux) or Remote Desktop (Microsoft Windows Server).
If you receive the message that the password is incorrect, check the credentials in the Cloud Panel and reset the root password (Linux) or the administrator password (Microsoft Windows) if necessary.
- If your server is running but can no longer be reached via SSH or remote desktop connection, then you can log onto the server using the KVM console. The KVM console allows you to remotely maintain the system as if you were sitting directly in front of it. For example, a faulty network configuration can be corrected directly in the system. How to open the KVM console is explained in the following article:
Accessing a Server using the KVM Console (Cloud Server and Virtual Server Cloud)
Check the Log Files
If you can establish a connection to your server, check the server's log files. When troubleshooting, consider updates and configuration changes that may have been made recently.
If you cannot connect to your server, continue to the next step.
Check the Firewall Policy and Rules
In the Infrastructure > Servers section of the Cloud Panel, check which firewall policy is assigned to the server.
In the Network > Firewall Policy section, check if the required ports have been opened in the assigned firewall policy. If necessary, assign the correct firewall policy to the server or create the necessary rules for the port releases in the assigned firewall policy, such as port 22 for SSH or port 3389 for RDP.
Try again to connect to the server via SSH (Linux) or Remote Desktop (Microsoft Windows Server).
Perform a Port Scan
If you cannot connect to the server after checking and, if necessary, adjusting the firewall policy in the Cloud Panel, perform a port scan. Check whether Port 22 (Linux) or Port 3389 (Microsoft Windows) are enabled.
If you are using Linux, you can use the netcat program to perform a port scan. Netcat (nc), is a universal command line tool. It can be used in the terminal or in scripts for communication via TCP and UDP network connections (Internet Protocol version 4 and version 6).
The netcat program is a part of every Ubuntu installation, but can be installed using the following commands when necessary.
[root@localhost ~]# apt-get update
[root@localhost ~]# apt-get install netcat
To install netcat on a server with the distribution CentOS, enter the following command:
CentOS 7, CentOS Stream 8 and 9
[root@localhost ~]# yum update
[root@localhost ~]# yum install -y nc
To perform a port scan with netcat, enter the following command:
nc -v IP-ADDRESS-OF-THE-SERVER PORTNUMBER
[root@localhost ~]# nc -v 192.168.1.1 22
To perform a port scan in Windows, enter the following command in the Powershell on your local computer:
Test-NetConnection IP-ADDRESS-OF-THE-SERVER -p PORTNUMBER
[root@localhost ~]# Test-NetConnection 192.168.1.1 -Port 22
If the required ports are blocked even after checking and, if necessary, adjusting the firewall policies, a check of the firewall settings in your operating system is required.
Check the Configuration of the Server
If you cannot connect to the server, log in to the server using the KVM console. Then check the network settings of the server.
The most important commands you need to check the network configuration can be found in the following article:
Checking the firewall configuration and the network settings (Linux)
Use Knoppix for Data Rescue If Access to the Operating System Is Not Possible
If you cannot access the operating system, you can boot your server using the Knoppix DVD and mount the partitions so that you can access the data via SSH or SFTP. Simply follow these steps:
In the Cloud Panel, insert the Knoppix DVD in the Infrastructure > Server section and restart the server. The server now boots with the Knoppix-DVD. The server now boots with the Knoppix DVD. After the restart of the the server, you can access Knoppix through the KVM console and create a backup of your data or change the configuration of your server. Step-by-step instructions can be found here:
If your server cannot boot with the Knoppix DVD or if you have problems with troubleshooting, please contact support.