Dns

Systemd-analyze

The command systemd-analyze helps analyzing systemd components to optimize the system including performance and security.

Summary

How to see the the network IP address of your system

Show the IP address of your system with the help of the ip command.

Summary

Show your local IP address

How to see the IP address of your internet connection

Show the IP address of your internet connection using the dig command.

Summary

Query the IP address of your internet connection

How to see which DNS server is used

Find the active DNS server being used by reviewing the network configuration, including common commands to query this information.

Summary

Show the active DNS server

Show to clear the DNS cache with systemd

Learn how to inspect and clear the DNS cache when using the systemd resolver daemon.

Summary

Clear DNS cache using resolvectl

Resolvectl

The command resolvectl provides details about systemd-resolved, the name resolution daemon.

Summary

How to see the TTL value of a DNS record

Learn how to query the Time To Live (TTL) for a DNS record by using the dig tool.

Summary

Query DNS to reveal the TTL value of a DNS record.

Linux DNS Tuning for Performance and Resilience

Linux DNS configuration is usually done during the installation of the system. With proper configuration and tuning, you gain performance and stability.

Summary

DNS Configuration on Linux

We often don’t realize the importance of DNS, or name resolving in our infrastructure. The impact when things go (slightly) wrong is huge. Time to have a good look at improving our DNS configuration.

How DNS resolving works

When your Linux system needs to know the IP address of a particular host, it will use gethostbyname(3) function. This will use the nsswitch configuration stored in /etc/nsswitch.conf. For the related hosts line, it will determine how to do resolving.