How to Clear DNS Cache on Linux Server
The DNS cache is a temporary database that stores interpreted DNS query information. In other words, whenever you visit a website, your operating system and web browser keep a record of the domain name and corresponding IP address.
This eliminates repeated queries to remote DNS servers and allows your operating system or browser to quickly resolve a website's domain name.
But in some cases, such as troubleshooting network issues or after changing DNS addresses, you may need to flush the DNS cache. This will clear cached DNS records to interpret domain names based on DNS addresses.
I'm Essie, today I'm going to talk to you about how to clear the dns cache in the linux system
There are usually two ways to clear the DNS cache in Linux: one is to use the DNS cache program NSCD (name service cache daemon) to manage the DNS cache. Another way to implement DNS caching is to use Bind to set up the Caching Name Server.
If you want to clear the Cache on NSCD, you can restart the NSCD service to achieve the effect of clearing the DNS Cache. with this command:
# service nscd restart
# /etc/init.d/nscd restart
If you are clearing the cache on the BIND server, use this command:
# rndc flush
If your DNS server is implemented with dnsmasq, use the following command
$ sudo /etc/init.d/dnsmasq restart
Note: DNSmasq is a lightweight and easy-to-use DNS service tool. It can be used for IP address NAT conversion when connecting to the intranet and the Internet, and can also be used as DNS service for small networks.
How to Clear DNS Cache in Other Operating Systems
1. How to clear dns under Microsoft Windows:
You can use the following command to clear dns cache content.
ipconfig /flushdns
You can also use the following command to view dns cache content.
ipconfig/displaydns
The DNS Cache under Windows is controlled by the DNS Client background process, you can turn it off in the Control Panel -> Service, so that Windows will not perform DNS caching, and will directly query the DNS Server every time.
How to clear the DNS cache under Mac OSX:
On Mac OSX, you can clear the DNS cache contents with the following command:
bash-2.05a$lookupd-flushcache
DNS cache can quickly obtain resolution records, but if the DNS resolution of the visited website changes, the local DNS cache cannot be synchronized in time, which may cause domain name resolution errors, and may even be illegally used for DNS hijacking to point domain name resolution to Illegal website. Therefore, in order to ensure the accuracy of DNS resolution, it is necessary to regularly clean up the DNS cache
What are the benefits of clearing DNS cache :
1. Security
DNS cache files are a prime target of DNS events, DNS spoofing, an attack that alters DNS records in order to redirect online traffic to a fraudulent website similar to its intended target. Flushing the DNS cache will empty most files (except those related to auto-updates), making this event less likely to occur.
2. Good connection
If the website is not loading on a particular device, but is loading on others, it is most likely due to DNS caching issues. By flushing the DNS cache, bad IP address entries will be removed and the correct/latest IP address will be used when making the next request.
3. Old data
Since there are many popular DNS providers, you may run into problems if you changed your DNS provider recently, but the cache still contains data from the old DNS provider.
4. Maintenance
Another benefit of flushing the DNS cache is that it is good practice for maintenance. Although DNS cache files don't take up a lot of space, the list will obviously grow rapidly over time if the cache is not flushed regularly. By flushing the cache, records are properly removed so that the resolver no longer uses the now-outdated information, and it also resolves 404 errors encountered when trying to access certain sites.
I'm Aixi, and that's all for today's sharing. I hope it will be helpful to friends in need. See you next time!