DNS Propagation is a term used to check the current status of global DNS results, often used when making any changes to DNS and not seeing the desired results.
The DNS Propagation process can take a few minutes, but in many cases, it can take up to 48 hours or even longer. The time required for this process generally depends on the Time To Live (TTL) settings of the DNS records, but there are other factors that can affect the duration of this process such as DNS Cache, ISPs and domain registrar.
What is DNS Caching and How Does It Contribute?
The goal of caching is to temporarily store information in a specific location to improve performance and better results when making a request to a specific website (i.e., when a user enters a web address in the browser).
Storing DNS or DNS caching allows the preservation of information closer to the user so that the mapping of the entered address is performed faster, and there’s no need for additional queries in the hierarchy chain of the mapping process. Hence, DNS caching leads to improved loading times and requires slightly less bandwidth and CPU.
This DNS cache information can be stored in various locations, each with a defined and specific expiration time set by the Time To Live (TTL) configuration.
Checking the DNS of Your Website’s Domain
If you want to check the DNS records of a specific domain or if you’re curious about the DNS records of your own website’s domain, you can use various tools available online.
One such tool is whatsmydns.net, which allows you to check the IP address associated with a specific domain, as well as various types of DNS records. Here’s a list of DNS records that you can check using this tool:
- A – The most common DNS record, used to point a domain to an IP address.
- CNAME – Also known as alias records, they point to other DNS records. Sometimes used for subdomains like www.
- MX – Mail Exchanger records are used to set email servers and their priority.
- NS – Name Server records store the authoritative nameserver.
- TXT – Text records are commonly used for configuration settings such as SPF and DKIM records.
DNS Records Cleanup in the Operating System – Flush DNS
Operating systems like Windows and others locally store IP addresses and related information for hostnames in order to access them quickly instead of repeatedly querying the DNS server.
When the operating system understands that a hostname corresponds synonymously to a specific IP address, it has the authority to keep this information or store it in the cache memory of the device.
And while this information storage can be useful, there are cases where the stored information is no longer up-to-date or corrupted.
Generally, operating systems remove this information after a certain period, but if you have trouble accessing a specific site and suspect a DNS issue, the first thing to do is to clear the cached data and make room for updated DNS records.
You can do this by simply rebooting your computer, as that action clears the DNS cache upon restart. Alternatively, you can perform a manual action called Flushing DNS, which is likely simpler than restarting the computer.
In the Windows operating system, you can do this through the Command Prompt using the following command:
ipconfig /flushdns
In the macOS operating system, you can do this using the Terminal:
sudo killall -HUP mDNSResponder
Here’s a more detailed list of the specific command for each operating system…
Local DNS Cleanup by Operating System
macOS Monterey 12.0.0
sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
macOS Big Sur 11.2.0
sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
macOS Catalina 10.15.0
sudo killall -HUP mDNSResponder
macOS Mojave 10.14.0
sudo killall -HUP mDNSResponder
macOS High Sierra 10.13.0
sudo killall -HUP mDNSResponder
macOS Sierra 10.12.0
sudo killall -HUP mDNSResponder
OSX 10.11.0
sudo killall -HUP mDNSResponder
OSX 10.10.4
sudo killall -HUP mDNSResponder
OSX 10.10.0 – 10.10.3
sudo discoveryutil mdnsflushcache
OSX 10.9 – 10.8 – 10.7
sudo killall -HUP mDNSResponder
OSX 10.5 – 10.6
sudo dscacheutil -flushcache
Windows
ipconfig /flushdns
Linux (depending on what you’re running)
/etc/init.d/named restart
/etc/init.d/nscd restart
It’s important to note that depending on how your router is configured, DNS records might also be stored in it. If clearing the local DNS record on your computer doesn’t solve the DNS issue you’re experiencing, try rebooting your router to see if it resolves the problem…
DNS records in the hosts file are not cleared when you clear DNS records. You need to edit the hosts file and manually delete the host names and IP addresses stored there.
That’s it.