How to Fix Slow DNS
DNS is queried on every new connection. Slow DNS adds 100–500 ms to every page load, every app launch, and every streaming session start — invisibly, because it happens before any data transfers. It is one of the fastest and easiest wins in home network optimisation. Updated 2026-04-27.
Step 1: Test your current DNS response time
On macOS/Linux: run dig google.com | grep 'Query time'. On Windows: run nslookup google.com and note the response. Under 20 ms is good; 50–200 ms is typical for ISP DNS; over 200 ms is slow and worth changing.
Step 2: Switch to a faster DNS server
In your router's DNS settings (usually under WAN or Internet settings), change the primary and secondary DNS:
- 1.1.1.1 / 1.0.0.1 (Cloudflare) — fastest globally; strong privacy
- 8.8.8.8 / 8.8.4.4 (Google) — excellent reliability; wide global network
- 9.9.9.9 / 149.112.112.112 (Quad9) — blocks malicious domains; privacy-focused
Step 3: Enable DNS caching
Most operating systems cache DNS results for the TTL period. If DNS caching is disabled or cleared frequently, every lookup goes to the server. On Windows, ensure the DNS Client service is running. On macOS, DNS caching is on by default. A local DNS resolver (Pi-hole, AdGuard Home) caches aggressively and reduces lookups to under 1 ms for repeat queries.
Step 4: Enable DNS-over-HTTPS or DNS-over-TLS
Standard DNS is unencrypted — your ISP can see and log every domain you look up. DNS-over-HTTPS (DoH) encrypts the lookup. Enable it in your router's DNS settings if supported, or in your browser (Chrome/Firefox both support it in Settings > Security > Use secure DNS). Cloudflare's 1.1.1.1 and Google's 8.8.8.8 both support DoH.
Frequently Asked Questions
Does changing DNS make the internet faster?
It improves page load start time for uncached domains by 20–200 ms per lookup. This is most noticeable when clicking many links rapidly (each new domain requires a fresh lookup). Download speed and streaming throughput are not affected — DNS only affects the lookup before the connection.
What DNS does my ISP use?
Your ISP's DNS is assigned automatically via DHCP when you connect. Run <code>ipconfig /all</code> (Windows) or <code>cat /etc/resolv.conf</code> (macOS/Linux) to see the current DNS servers. ISP DNS typically has slower response times than Cloudflare or Google and logs your lookups.
Is 1.1.1.1 safe to use?
Yes. Cloudflare's 1.1.1.1 is one of the most widely used and privacy-respecting public DNS resolvers. Cloudflare commits to not logging IP addresses that query the resolver beyond 25 hours and to not selling browsing data. Their DNS-over-HTTPS implementation also prevents ISP interception.
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