5. Technical checks

The system allows to check the technical state of name servers and report results to administrators of the name servers or registrars.

Technical checks are performed periodically and/or on demand from registrars.

A technical check consists of one or more individual tests with graded severity which are applied to a name server within a name-server set in a certain order. Some tests focus on the basic functionality of a name server and others on greater details which, if not satisfied, do not actually jeopardise domain delegation.


The tests are only informative, they do not affect inclusion/exclusion of a domain in/from a zone.

Each test has a unique name that describes the name-server property to be tested. Test severity indicates the significance of failure of a given test. Severity is represented by an integer number on the scale from 0 to 10. The lower the number, the higher the severity of a test.

Only if a test of higher severity passed, then a test of lower severity is performed.

The test result is one of the following:

  • Test passed
  • Test failed
  • Unknown result

The unknown result represents a situation in which the test ended in an unexpected error or unexpected circumstance that prevented achievement of a passed/failed result.

Each nsset may contain information about the severity level that should be tested for it (the report level attribute) but this can be overridden when a check is being requested by a registrar via the EPP interface. If neither provides this information, the default level is tested (FRED’s default: 3, configurable). Currently, there are no level-0 tests and the highest level in use is 6.

Individual tests
Test name Severity Depends on Description
Glue_OK 1   Tests whether there is a glue record when required for a given DNS server and domains.
Existence 1 Glue_OK Tests whether the DNS server is running.
Presence 2 Glue_OK, Existence Tests the presence of the record of the domain on the DNS server.
Authoritative 3 Glue_OK, Existence, Presence Tests whether the DNS server’s response to a particular domain is authoritative.
NotRecursive 4 Glue_OK, Existence Tests whether the DNS server is recursive based on what the DNS server says about itself.
NotRecursive4all 4 Glue_OK, Existence Tests whether the DNS server is recursive based on a practical test.
Autonomous 5 Glue_OK, Existence At least two of the DNS servers must be in different autonomous systems.
Heterogeneous 6 Glue_OK, Existence At least two DNS servers with different software.

If a check is requested by a registrar via EPP, the results are delivered to the registrar in a EPP poll message.

If a periodic check fails, technical contacts of an nsset are notified by email which informs also about the cause of the failure.