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Automatic DNSSEC provisioning

After you or your DNS operator has setup DNSSEC on the zone, DS records need to be inserted into the parent zone (.com, .net, etc) to complete the chain of trust from the ICANN root zone. This process can be annoying and prone to minor errors even with the ever handy copy paste.

CDS and CDNSKEY records allow for automatic setup, rollover, and removal of DNSSSEC delegation for a zone. These are identical copies of what the child zone wants in the parent, hence Child DS and Child DNSKEY. We will poll the nameservers of all domains every hour to detect these records and make any changes in the parent as requested by the records.

For the sneaky techy deets we implement this according to RFC 7344 and RFC 8078. HexDNS implements CDS and CDNSKEY, and this is on by default, so you won't have to do anything to get HexDNS to provision DNSSEC automatically with us or any other regstrar/registry.

Format of child records

Consider the following DS record in the parent zone:

website.example. 3600 IN DS 61301 13 2 FB7DF3397DB9AEA62EB81423CA1BB229CCAE3590DCBB16CE46C04D62B48DFB91

When the DS record of the new KSK is ready to be published in the parent zone, the child can set the following record:

website.example. 3600 IN CDS 45224 13 2 8A7BD58EF0CFA7FFD3813B28A288C69DE9D38D3B5FE71816E82AE26AF0615165

Once this has been picked up the new DS in the parent zone will be:

website.example. 3600 IN DS 45224 13 2 8A7BD58EF0CFA7FFD3813B28A288C69DE9D38D3B5FE71816E82AE26AF0615165

A chhild zone can also signal to turn off DNSSEC by publishing a special CDS record with an algorithm of 0, as follows:

website.example. 3600 IN CDS 0 0 0 00

The procedure is identical for CDNSKEY, but with the DS data swapped out for DNSKEY data. Some zones (notably .de) require to be sent DNSKEY data rather than DS data and compute the DS record themselves. For this reason it is advisable to publish both CDS and CDNSKEY and the appropriate one will be used.

Criteria for acceptance into parent zone

Before records are accepted into the parent zone a few criteria must be met. This are as follows:

  • Every name server must respond on every listed IP address over TCP with identical CDS sets.
  • If the zone is already signed with DNSSEC the CDS record set must be singed by the current published DS/DNSKEY record set.
  • CDS/CDNSKEY must use a supported algorithm and digest type;
    • algorithms: 5, 7, 8, 10, 13, 14, 15, 16, 0
    • digest types: 1, 2, 4, 0
  • The zone must validate with the new CDS set.

Post acceptance

Once we've received the request, validated, and successfully enacted upon it, we'll send you an email with a summary of what DS/DNSKEY records have been added/removed.


Last update: October 26, 2020