DNS cache stores the results of domain name lookups so your device can find websites faster. When you visit a website, your computer translates the domain name (like example.com) into an IP address. Rather than asking a distant DNS server every time, your device saves this translation temporarily and reuses it for subsequent visits.
DNS caching happens at multiple levels. Your device (computer, phone, router) maintains a local cache, your internet service provider (ISP) runs its own cache, and the website's DNS provider caches entries as well. Each cached entry has a time-to-live (TTL) value that determines how long it remains valid before expiring and requiring a fresh lookup.
Why this matters: DNS caching dramatically reduces latency when loading websites. Without it, every page load would pause while your device waits for a distant server to respond. For users, faster DNS lookups mean snappier web browsing and quicker app connections.
Common gotchas include stale cache entries. If a website moves to a new server or changes its IP address, your cache might still point to the old address until the TTL expires, causing connection failures. This is why DNS changes can take hours or days to propagate fully.
You can clear your DNS cache manually on Windows using the command prompt, on Mac via terminal, or on your router's settings panel. This forces fresh lookups and helps resolve connectivity problems when DNS records have recently changed. Some users also switch to third-party DNS services like Cloudflare (1.1.1.1) or Google DNS (8.8.8.8) to benefit from their larger, faster caches.