What is DNSSEC?
The DNS Security Extensions (DNSSEC) is a set of protocol extensions to DNS to digitally sign DNS information. This provides
source authentication and integrity protection for DNS data and responses. DNSSEC is completely opt-in: clients must signal that they
want DNSSEC information included in responses. Trust in DNSSEC is built upon the hierarchy already established in the DNS. Parent zones (e.g.
".gov") vouch for the security state of its child delegations (e.g. "nist.gov"). DNSSEC is mandated for use in the US Federal government
and included in FISMA.
Clients must have one or more validation keys pre-configured in order to validate DNSSEC responses. Keys higher in the DNS hierarchy
are preferred as then trust can be established for all delegations under that node in the DNS. For example, the key for .gov can be used
to build trust in any DNSSEC signed domain under .gov. The DNS Root Zone (".") is the top node of the entire DNS tree. Clients configured
to use the Root Zone key for DNSSEC will be able to validate any DNSSEC signed zone.
Root Zone DNSSEC Key Rollover
The Root Zone first deployed DNSSEC in 2010. With any secure protocol deployment, a regular changing of keys is necessary as part of
normal operations. This key updating (called a "key rollover") will take place this year (2017). The Internet Corporation for Names
and Numbers (ICANN), the entity that manages the DNS Root Zone, has developed and executing their plan to roll over the Root
The ICANN plan for the Root Zone key rollover is documented on their website. The major milestones are:
- October 27, 2016: KSK rollover process begins as the new KSK is generated.
- July 11, 2017: Publication of new KSK in DNS.
- September 19, 2017: Size increase for DNSKEY response from root name servers.
- October 11, 2017: New KSK begins to sign the root zone key set (the actual rollover event!).
- January 11, 2018: Revocation of old KSK.
- March 22, 2018: Last day the old KSK appears in the root zone.
- August 2018: Old key is deleted from equipment in both ICANN Key Management Facilities.
What DNS Administrators Need to Know
First, the KSK rollover only affects DNS recursive resolvers that have been configured to use DNSSEC. If DNSSEC is not configured, then the
Root Zone rollover will not impact current operation.
If DNSSEC validation is used, the administrator has two options:
- Configure automated key rollover: Most DNS implementations now support the automated key rollover protocol
specified in RFC 5011. This protocol enables a DNSSEC client to automatically update its trusted keys when the trusted DNS zone
signals that it is changing its key. How this configuration is done is implementation specific, so administrators should consult
their implementation's documentation. Automated key rollover can be tested using the
ICANN KSK Rollover Testbed. This requires the use of
a test system, as production systems should not use the testbed (it is not a full root zone). Administrators should
monitor their systems during major operations in the rollover time frame (see above). If a large number of errors are seen on the day of or
immediately after an event, this could mean that the automated rollover did not work, or encountered an error. Administrators may have to
the resort to manually updating the Root Zone key (see 2 below).
- Manual key rollover: If the given DNS client uses DNSSEC, but does not support the automated key rollover protocol,
administrators must update the key manually. How this is done is implementation specific, so administrators should consult
their implementation's documentation. The new Root Zone key can be added to the set of trusted keys at any time, but should be added before
the old key is revoked in order to ensure continued operation. From the posted roadmap, this date is October 11, 2017. Therefore,
the new Root Zone key (that is already published), must be added before October 11th, 2017.
- ICANN presentation at NANOG (PDF). Includes the new root KSK that can be copied for manual KSK rollover.
- gov-dns mailing list: A mailing list for government DNS administrators. Only open to those with .gov/.mil email addresses
or those directly supporting a .gov/.mil delegation operation. To join, send an email message to firstname.lastname@example.org
with "subscribe" in the message subject.
- dnssec.net: Clearinghouse for DNSSEC related information, including links to training, tools, and documents.
- Deploy360: Internet Society's news blog dealing with DNSSEC.
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Date created 7/13/2017. Last updated