DNS
How your device finds a website by name
What is DNS?
DNS helps your device find a website by name. It looks up an address your device can connect to. Your browser, device, and DNS service can save answers for reuse. These saved answers are called a cache, so a fresh lookup is not needed for every visit or connection. Cloudflare explains the lookup and caching process.
When might DNS matter?
A slow lookup can delay the start of a page load. A failed lookup can stop a site opening even while other internet services work. But that pattern alone does not prove DNS is the cause: the site, browser, VPN, or filtering service may also be involved.
Changing DNS will not fix weak WiFi or increase the capacity of your internet plan. A call that connects and then freezes needs broader checks.
What to check first
- Note the exact browser error and whether one site or several fail. Try a second familiar site.
- Compare another device on the same WiFi. On a phone, ensure it is not using mobile data for the comparison. If only one device fails, start there.
- On hotel or café WiFi, check whether you still need to complete the network's sign-in page. Ask staff for help if it does not appear.
- If DNS is still a possible cause, read the DNS setup guide for a reversible test on one Mac. Ask IT first on a work device or network.
Keep notes of what worked, what failed, and the time. Send them to your provider or IT team if the problem continues. Avoid changing the whole household's DNS to investigate one device.
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