Critical Ubuntu Server Issues: DNS Resolution & Package Management Failures [closed]

I'm encountering a series of issues on my Linux server (srv486284) and could use some assistance in resolving them:

1. DNS Resolution Issue: When trying to ping google.com, I get a "Temporary failure in name resolution" error.

2. Missing netplan Command: Despite trying to apply network configurations with netplan, I'm told the command isn't found (sudo: netplan: command not found).

3. Package Installation Error: Attempting to install netplan results in a message saying "Package 'netplan' has no installation candidate".

4. Repository Fetch Failures: During apt-get update, I'm seeing errors like "Temporary failure resolving 'us.archive.ubuntu.com'".

Could anyone provide insights or steps to troubleshoot these issues? I've checked my network connectivity and firewall settings, but I'm still stuck.

1. Error 1: Temporary failure in name resolution

   • Command:ping google.com
   • Error Message:ping: google.com: Temporary failure in name resolution
   • Explanation: This error indicates a DNS resolution issue. The system cannot resolve the domain name google.com to its corresponding IP address.

2. Error 2: Command not found for netplan

   • Command:sudo netplan apply
   • Error Message:sudo: netplan: command not found
   • Explanation: This error occurs when the netplan command-line tool is not installed or cannot be found in the system's PATH. It suggests that netplan might not be installed on your system.

3. Error 3: Package 'netplan' has no installation candidate

   • Command:sudo apt-get install netplan

   • Error Message:

     Package netplan is not available, but is referred to by another package.This may mean that the package is missing, has been obsoleted, oris only available from another sourceE: Package 'netplan' has no installation candidate

   • Explanation: This error indicates that the netplan package cannot be found in the repositories configured on your system. It might be missing or not supported by your current distribution/version.

4. Error 4: Temporary failure resolving repositories

   • Command:sudo apt-get update

   • Error Message:

     Temporary failure resolving 'us.archive.ubuntu.com'Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/lunar/InRelease

   • Explanation: These errors indicate that the system is unable to reach the Ubuntu package repositories (us.archive.ubuntu.com). This can be due to network connectivity issues, DNS problems, or repository server downtime.

Thanks in advance for any help you can offer!

To resolve the network and package issues on my Ubuntu server, we initially tried troubleshooting the DNS resolution problem by restarting the systemd-resolved service and modifying the DNS settings via NetworkManager. We then attempted to configure the network interface using both NetworkManager and netplan, only to encounter various errors, such as missing netplan commands and persistent unmanaged states for the network device. Despite enabling and restarting relevant services, the server continued to face DNS resolution failures and package update errors. Our efforts included checking network configurations, ensuring services were active, and exploring potential package installation solutions, but the issues remain unresolved.