How to Find a local DNS resolver?
Before starting the DNS Cache flushing process, we need to find the local DNS resolver on our system. So to find that we can execute the following command to determine the local DNS resolver on our Linux system.
sudo lsof -i :53 -S
- lsof: The lsof command is used to list open files and associated processes.
- -i :53: This specifies the query for processes using port 53, which is the default port for DNS.
- -S: This option shows the processes associated with the specified socket.
In the output, we can see that our process is associated with port 53 which mentions “systemd-resolved“. So this is our local DNS resolver.
How to Flush the DNS Cache in Linux?
Flushing the Domain Name System (DNS) cache in Linux is a common troubleshooting step to resolve various networking issues and ensure the system retrieves the most up-to-date information when resolving domain names to IP addresses. The DNS cache stores previously resolved domain names and their corresponding IP addresses, reducing the time and resources required for subsequent requests. However, sometimes, outdated or incorrect information may be cached, leading to connectivity problems. Flushing the DNS cache in Linux involves clearing this stored data, prompting the system to require DNS servers for the latest information. This process can be crucial for resolving issues such as domain resolution errors, website inaccessibility, or changes in DNS configurations. This article will explore the methods to flush the DNS cache on various Linux distributions, providing users with a comprehensive guide to effectively manage and troubleshoot DNS-related issues.
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