Czech Republic DNS Propagation Checker
Run a DNS lookup against 6 resolvers located in Czech Republic — Znojmo · Prague · Prague · Klatovy · Hanušovice · Prague.
- Resolved
- No answer
- Checking
-
Znojmo
Czechia
—
-
Prague
Czechia
—
-
Prague
Czechia
—
-
Klatovy
Czechia
—
-
Hanušovice
Czechia
—
-
Prague
Czechia
—
What checking DNS from Czech Republic tells you
A DNS resolver keeps a cached copy of each record for as long as its time-to-live allows, and does so separately in every location. A change you have published can be live on one resolver while another still serves the old answer.
Checking from Czech Republic looks up the record on servers inside the country, so you see what people there actually get rather than what a resolver on another continent returns.
This matters most right after you edit a record: an update visible on a global resolver like 8.8.8.8 can still be stale at a local ISP in Czech Republic until its cached copy expires. The check confirms the new value has reached the resolvers your Czech Republic visitors depend on.
Czechia is one of the few countries where the domain registry also writes DNS software the rest of the world runs. CZ.NIC, which manages the .cz zone, built Knot DNS and Knot Resolver and operates a free public resolver called ODVR (Open DNSSEC Validating Resolvers) at 193.17.47.1 as an alternative to Google or Cloudflare. It validates DNSSEC and applies no content filtering.
Most Czech households never touch ODVR, though. They use whatever their access provider hands out: O2, on CETIN's wholesale network since the 2015 split, or Vodafone, which absorbed UPC's cable footprint in 2019. Checking a record from inside Czechia shows what those ISP resolvers return, which isn't always what a public resolver says.
Since the 2017 Gambling Act, Czech access providers must block unlicensed gambling domains from a list the Ministry of Finance publishes — several hundred entries and growing, now folded into a single machine-readable Uniform List of Blocked Websites that the telecom regulator (ČTÚ) began publishing on 1 January 2026. Those domains resolve normally on ODVR or 8.8.8.8 but fail through a compliant ISP resolver.
- CZ.NIC ODVR193.17.47.1 National .cz registry's open DNSSEC-validating resolver, unfiltered
- O2 Czech Republic Incumbent retail ISP on CETIN's network; most households, mandatory blocks
- Vodafone Czech Republic Major fixed/cable provider (absorbed UPC in 2019); applies the same state blocklist
Some answers from Czech ISP resolvers reflect the state's mandatory DNS blocklist for unlicensed gambling (and, briefly in 2022, several disinformation domains), so a blocked domain can resolve differently through a local ISP than through a public resolver like CZ.NIC's ODVR.
How DNS propagation works
Every DNS record carries a time-to-live: the seconds a resolver may keep its cached answer before asking again. Change a record and resolvers holding the old value keep serving it until that timer runs out.
Propagation is this expiry playing out across many independent resolvers, so a lower time-to-live set ahead of a change makes it take effect sooner. There is no fixed waiting period — each record's time-to-live decides how long the old answer lingers.
Frequently Asked Questions
Why do DNS servers in Czech Republic return different results than 8.8.8.8?
Two things cause it. Each resolver caches independently, so one can hold an older answer than another.
And content delivery networks reply based on where the asking resolver is, steering a resolver in Czech Republic toward a nearby edge node.
Both answers can be correct at the same time for their own location.
How long until a DNS change is visible in Czech Republic?
It depends on the record's time-to-live, not on the country.
Resolvers in Czech Republic keep the previous answer until their cached copy expires, then pick up the new one.
If you lowered the time-to-live before making the change, it appears sooner; otherwise the old value can persist until the original timer elapses.
Which DNS server should users in Czech Republic use?
For most people the resolver their internet provider assigns is fine and usually the lowest latency.
Anyone who wants an alternative can point to a public resolver reachable from Czech Republic, such as Cloudflare (1.1.1.1) or Google (8.8.8.8); the right choice depends on whether you value speed, privacy, or filtering.
Why check DNS from Czech Republic specifically?
Because it shows what visitors in Czech Republic actually resolve, which can differ from a global lookup.
If your audience is in Czech Republic, or you have moved hosting or mail there, checking against in-country resolvers confirms the records have reached the servers those users rely on.
Does the CZ.NIC ODVR public resolver block any sites?
No. ODVR (193.17.47.1 and 185.43.135.1) is run by CZ.NIC, the .cz registry, as a DNSSEC-validating resolver with no content filtering. The mandatory gambling-blocklist obligation falls on internet access providers, not on this public resolver, so a domain your ISP blocks will usually still resolve through ODVR. The one exception in recent memory was 2022, when CZ.NIC briefly suspended eight domains spreading Russian war propaganda after the invasion of Ukraine.
Why would a site resolve here but not through my Czech ISP?
The Ministry of Finance keeps a list of unlicensed gambling sites that ISPs must block at the DNS level within 15 days of listing, and from January 2026 the Czech Telecommunication Office (ČTÚ) publishes a consolidated Uniform List of Blocked Websites covering gambling plus illegal medicines and food. If a domain is on that list, a compliant Czech ISP resolver returns a block or NXDOMAIN while a public or global resolver returns the real record.
