CZ.NIC ODVR

CZ.NIC ODVR (Open DNSSEC Validating Resolvers) are public DNS resolvers run by CZ.NIC, the Czech interest association that operates the .cz domain registry. CZ.NIC was founded in 1998 by fifteen leading internet providers, is registered in Prague and also develops the Knot DNS software, including Knot Resolver. The resolvers are free to use instead of the ones offered by an internet provider.

Features

• DNSSEC validation: answers for signed domains are checked, so manipulated records are rejected
• IPv4 addresses 193.17.47.1 and 185.43.135.1, plus two IPv6 addresses
• Encrypted access via DNS over TLS (port 853) and DNS over HTTPS at odvr.nic.cz
• No filtering of any kind: the resolver answers what the authoritative servers say

Limits

ODVR is a plain, neutral resolver. It has no malware or ad blocking, no variants, no accounts and no app. CZ.NIC points out itself that DNSSEC protects only signed domains and that most applications do not check it, so the benefit depends on the setup. The ODVR page does not describe a logging policy, so anyone who needs a stated retention period should check the operator's privacy documents or choose a resolver with a dedicated policy such as Quad9 or DNS4EU.