DNS services

DNS resolving

Resolving the DNS issues (conversion of names into IP addresses and vice versa) in the entire infrastructure and networks connected without any limitations. DNS servers offering the service are:

  • cesnet.cz–, 2001:718:1:1::2
  • ces.net–, 2001:718:1:101::3

Each participant of the CESNET e-infrastructure may use the services of the servers.

DNS delegation

CESNET ensures primary and secondary DNS servers for the delegation of zone files (name domains, domains in-addr.arpa and ip6.arpa).

Key benefits

  • No need to install own DNS server or a secondary DNS server in small networks;
  • High level of DNS service provision; shifting another secondary zone delegation outside own network.
  • Protection against DDoS attacks.

Target audience

The service is available to entities connected to the CESNET e-infrastructure.


The service is available to all entities connected free of any additional charge.

Terms of use

DNS resolving is provided to all users of the CESNET e-infrastructure without any limitations.

DNS delegation is provided in accordance with the following terms of use:

  • Name domain the delegation of which is being established on the DNS servers of the association should be operated in accordance with the Terms and conditions for the access to the CESNET Large infrastructure.
  • The domain should be correctly delegated in the superior domain;
  • Thein-addr.arpa or arpa domains must administratively belong into the autonomous systems of the CESNET3 networks, or must contain PI addresses which are routed in the AS of the CESNET3 network.


DNS resolving can be set up by the participant. Entities interested in the DNS delegation should send their request to the User care department.

Related services

Last change: 8.11.2023