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Czechia ISP DNS Servers
33 internet service providers listed — 30 with known DNS server addresses. ISP DNS servers are typically private and only work for that ISP's customers.
We list ISP DNS servers from 240 countries, with a total of 4,367 entries. Browse all countries
Note: ISP DNS servers are not public — they only work for customers of that specific ISP. If you want DNS that works from any connection, use public DNS servers instead.
Major National ISP
3 providers
O2 Czech Republic
Position:Major provider
Coverage:Nationwide
Technology:Fiber, DSL
DNS Servers:Not publicly documented — auto-assigned via DHCP
T-Mobile Czech Republic
Position:Major provider
Coverage:Nationwide
Technology:Mobile, Fiber
DNS Servers:Not publicly documented — auto-assigned via DHCP
Vodafone Czech Republic
Position:Major provider
Coverage:Nationwide
Technology:Mobile
DNS Servers:Not publicly documented — auto-assigned via DHCP
For most users in Czechia, the answer is no. ISP DNS servers are convenient because they work automatically, but they come with significant drawbacks. Many ISPs log every domain you visit, some sell aggregated browsing data to advertisers, and others practice NXDOMAIN hijacking — redirecting failed lookups to search pages filled with ads. ISP DNS servers also tend to be slower than dedicated public resolvers like Cloudflare or Google, especially during peak hours when they are overloaded with traffic from millions of customers.
Switching to a public DNS provider gives you better speed, stronger privacy, DNSSEC validation to prevent spoofing attacks, and the option for encrypted DNS via DoH or DoT. The change takes less than two minutes on any device.
O2 Czech Republic operates its own DNS resolvers for customers. The specific IP addresses are listed above. These servers only work on O2 Czech Republic's network and may change without notice. For a reliable alternative, consider public DNS providers like Cloudflare (1.1.1.1) or Google (8.8.8.8).
Does my Czechia ISP intercept DNS queries?
Some ISPs in Czechia practice NXDOMAIN hijacking, redirecting failed DNS lookups to their own search or advertising pages instead of returning a proper error. You can test this using our DNS Privacy Check tool. If your ISP hijacks DNS, switching to a public resolver eliminates this.
How do I change my DNS from my ISP's default?
On Windows: Settings > Network > your adapter > DNS > set to Manual and enter 1.1.1.1 and 1.0.0.1. On Mac: System Settings > Network > DNS. On your router: access the admin panel (usually 192.168.1.1) and change DNS in WAN/Internet settings. This overrides your ISP's DNS for all devices.
Is my ISP's DNS slower than Google or Cloudflare?
Often yes. ISP DNS servers can be overloaded during peak hours, while public DNS providers like Cloudflare and Google operate massive anycast networks optimised for speed. Use our DNS Gaming Benchmark to test latency from your actual location and see which is fastest for you.
What is NXDOMAIN hijacking and does my ISP do it?
NXDOMAIN hijacking occurs when your ISP redirects non-existent domain lookups to their own servers instead of returning the standard NXDOMAIN error. This can break applications, interfere with email validation, and expose your browsing to tracking. Run our DNS Privacy Check to detect if your ISP does this.
Last updated: . Data sourced from network scans and public records — ISPs may change DNS servers without notice.