Flushing your DNS cache is separate from flushing your Browser cache.
Your computer’s operating system will save DNS information for sites you’ve recently visited, to load them faster. Sometimes that old information can conflict with the site’s most recent version
If your computer’s DNS cache is old or bad, some sites might just “not load”. They load on other computers, just not on yours.
Where I’ve seen this most, is when I use a notebook that hasn’t been used for a while. I mainly work on my desktop computer; the notebook I might not use for many weeks.
If a website hosting company changes the IP address of the server a site is on, the DNS records need to be updated. Normally that update happens seamlessly (probably with a “change of address” notice, for a while). If it doesn’t happen seamlessly, you can manually clear your DNS cache, so all DNS entries will be queried anew.
Types of Errors That Have Pages Not Load
<div id="si-preloader"> ...<!-- Probably stuff here --> </div><!-- END .si-preloader-1 -->
Change this to not display the preloader, like this:
<div id="si-preloader" style="display:none;" >
You would see errors like “This site’s domain name is either not yet pointed or is still propagating. Propagation may take up to 72 hours. Please check back later.”
400 Bad Request
You might get a “400: Bad Request” error in your browser (similar to how when you attempt to visit a page that doesn’t exist, you get a “404 Not Found” error).
Flush DNS Cache In Windows
open the command prompt (tap the Windows key, type cmd and press Enter).
Flush DNS Cache In OS/X
sudo killall -HUP mDNSResponder
If that doesn’t work, try
sudo discoveryutil udnsflushcaches
For more on mDNSResponder, http://manpagez.com/man/8/mDNSResponder/
Flush DNS Cache In Linux Mint and Ubuntu
sudo systemctl is-active systemd-resolved
sudo systemd-resolve --statistics
Responds with output like this:
"DNSSEC supported by current servers: no" Transactions Current Transactions: 0 Total Transactions: 924990 Cache Current Cache Size: 74 Cache Hits: 16066 Cache Misses: 3662 DNSSEC Verdicts Secure: 0 Insecure: 0 Bogus: 0 Indeterminate: 0
use this command to flush your DNS cache:
sudo /etc/init.d/dns-clean start
Troubleshoot DNS — DIG Command
The dig command in Linux is used to gather DNS information. It stands for Domain Information Groper, and it collects data about Domain Name Servers. The dig command is helpful for troubleshooting DNS problems, but is also used to display DNS information.
dig -v confirm you have it installed dig google.com
The most important section is the ANSWER section:
The first column in the Answer section, lists the name of the server that was queried
The second column is the Time to Live, a set timeframe after which the record is refreshed
The third column shows the class of query – in this case, “IN” stands for Internet
The fourth column displays the type of query – in this case, “A” stands for an A (address) record
The final column displays the IP address associated with the domain name
; <<>> DiG 9.11.3-1ubuntu1.15-Ubuntu <<>> google.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 38377 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 65494 ;; QUESTION SECTION: ;google.com. IN A ;; ANSWER SECTION: google.com. 114 IN A 188.8.131.52 ;; Query time: 158 msec ;; SERVER: 127.0.0.53#53(127.0.0.53) ;; WHEN: Wed Jan 12 16:33:56 MST 2022 ;; MSG SIZE rcvd: 55
If a new domain name shows no IP address
dig preludemusicstudio.com ; <<>> DiG 9.16.1-Ubuntu <<>> preludemusicstudio.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 47922 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 65494 ;; QUESTION SECTION: ;preludemusicstudio.com. IN A ;; Query time: 244 msec ;; SERVER: 127.0.0.53#53(127.0.0.53) ;; WHEN: Mon Jul 25 10:58:35 MST 2022 ;; MSG SIZE rcvd: 51
Notice there is no “Answer Section” after “Question Section”? That tells you that the DNS record for the domain name hasn’t propagated to wherever your computer gets the DNS information from.
If you have moved the hosting for the domain name to a different hosting company, look to see the new server IP address showing.
When new domain propagated to the host
See IP address of the host, in the Answer section? (IN A 184.108.40.206)
dig preludemusicstudio.com ; <<>> DiG 9.16.1-Ubuntu <<>> preludemusicstudio.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 19329 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 65494 ;; QUESTION SECTION: ;preludemusicstudio.com. IN A ;; ANSWER SECTION: preludemusicstudio.com. 5401 IN A 220.127.116.11 ;; Query time: 3 msec ;; SERVER: 127.0.0.53#53(127.0.0.53) ;; WHEN: Mon Jul 25 12:07:21 MST 2022 ;; MSG SIZE rcvd: 67
Long delay on web pages that use Google Fonts
TecAdmin — https://tecadmin.net/flush-dns-cache-ubuntu/
“Our systems keep a cache of DNS records, which allows for faster resolution of IP address. After changing of IP address of any domain, it takes time to update local cache. In the meantime, you may get a broken page error. In this situation, you need to flush the local DNS cache.”
In terminal, use this command to flush your DNS cache:
sudo /etc/init.d/dns-clean start
For other operating systems and a full rundown of DNS caching as a whole, you can check out Kinsta’s excellent guide: How to Flush DNS Cache (Windows, Mac, Chrome)