Product Documentation

Zone Maintenance

Aug 31, 2016

From a DNSSEC perspective, zone maintenance involves rolling over Zone Signing Keys and Key Signing Keys when key expiry is imminent. These zone maintenance tasks have to be performed manually. The process of re-signing a zone is performed automatically and does not require manual intervention.

This document includes the following information:

Re-Signing an Updated Zone

Updated: 2014-08-27

When a zone is updated, that is, when new records are added to the zone or existing records are changed, the process of re-signing the new (or modified) record is performed automatically by the Citrix® NetScaler® ADC. If a zone contains multiple Zone Signing Keys, the ADC re-signs the new (or modified) record with the key with which the zone is signed at the point in time when the re-signing is to be performed.

Rolling Over DNSSEC Keys

Updated: 2014-08-27

On the NetScaler ADC, you can use the pre-publish and double signature methods to perform a rollover of the Zone Signing Key and Key Signing Key. More information about these two rollover methods is available in RFC 4641, “DNSSEC Operational Practices.”

The following topics map commands on the ADC to the steps in the rollover procedures discussed in RFC 4641.

The key expiry notification is sent through an SNMP trap called dnskeyExpiry. Three MIB variables, dnskeyName, dnskeyTimeToExpire, and dnskeyUnitsOfExpiry are sent along with the dnskeyExpiry SNMP trap. For more information, see Citrix NetScaler SNMP OID Reference at .

Pre-Publish Key Rollover

RFC 4641, “DNSSEC Operational Practices” defines four stages for the pre-publish key rollover method: initial, new DNSKEY, new RRSIGs, and DNSKEY removal. Each stage is associated with a set of tasks that you must perform on the ADC. Following are the descriptions of each stage and the tasks that you must perform. The rollover procedure described here can be used for both Key Signing Keys and Zone Signing Keys.

  • Stage 1: Initial. The zone contains only those key sets with which the zone has currently been signed. The state of the zone in the initial stage is the state of the zone just before you begin the key rollover process.

    Example

    Consider the key, example.com.zsk1, with which the zone example.com is currently signed. The zone contains only those RRSIGs that were generated by the example.com.zsk1 key, which is due for expiry. The Key Signing Key is example.com.ksk1.

  • Stage 2: New DNSKEY. A new key is created and published in the zone (that is, the key is added to the ADC), but the zone is not signed with the new key until the pre-roll phase is complete. In this stage, the zone contains the old key, the new key, and the RRSIGs generated by the old key. Publishing the new key for the complete duration of the pre-roll phase gives the DNSKEY resource record (that corresponds to the new key) enough time to propagate to the secondary name servers.

    Example

    A new key example.com.zsk2 is added to the example.com zone. The zone is not signed with example.com.zsk2 until the pre-roll phase is complete. The example.com zone contains DNSKEY resource records for both example.com.zsk1 and example.com.zsk2.

    NetScaler commands

    Perform the following tasks on the ADC:
    • Create a new DNS key by using the create dns key command.

      For more information about creating a DNS key, including an example, see Creating DNS Keys for a Zone.

    • Publish the new DNS key in the zone by using the add dns key command.

      For more information about publishing the key in the zone, including an example, see Publishing a DNS Key in a Zone.

  • Stage 3: New RRSIGs. The zone is signed with the new DNS key and then unsigned with the old DNS key. The old DNS key is not removed from the zone and remains published until the RRSIGs that were generated by the old key expire.

    Example

    The zone is signed with example.com.zsk2 and then unsigned with example.com.zsk1. The zone continues to publish example.com.zsk1 until the RRSIGs that were generated by example.com.zsk1 expire.

    NetScaler commands

    Perform the following tasks on the ADC:
    • Sign the zone with the new DNS key by using the sign dns zone command.
    • Unsign the zone with the old DNS key by using the unsign dns zone command.

    For more information about signing and unsigning a zone, including examples, see Signing and Unsigning a DNS Zone.

  • Stage 4: DNSKEY Removal. When the RRSIGs that were generated by the old DNS key expire, the old DNS key is removed from the zone.

    Example

    The old DNS key example.com.zsk1 is removed from the example.com zone.

    NetScaler commands

    On the ADC, you remove the old DNS key by using the rm dns key command. For more information about removing a key from a zone, including an example, see Removing a DNS Key.

Double Signature Key Rollover

RFC 4641, “DNSSEC Operational Practices” defines three stages for double signature key rollover: initial, new DNSKEY, and DNSKEY removal. Each stage is associated with a set of tasks that you must perform on the ADC. Following are the descriptions of each stage and the tasks that you must perform. The rollover procedure described here can be used for both Key Signing Keys and Zone Signing Keys.

  • Stage 1: Initial. The zone contains only those key sets with which the zone has currently been signed. The state of the zone in the initial stage is the state of the zone just before you begin the key rollover process.

    Example

    Consider the key, example.com.zsk1, with which the zone example.com is currently signed. The zone contains only those RRSIGs that were generated by the example.com.zsk1 key, which is due for expiry. The Key Signing Key is example.com.ksk1.

  • Stage 2: New DNSKEY. The new key is published in the zone and the zone is signed with the new key. The zone contains the RRSIGs that are generated by the old and the new keys. The minimum duration for which the zone must contain both sets of RRSIGs is the time required for all the RRSIGs to expire.

    Example

    A new key example.com.zsk2 is added to the example.com zone. The zone is signed with example.com.zsk2. The example.com zone now contains the RRSIGs generated from both keys.

    NetScaler commands

    Perform the following tasks on the ADC:
    • Create a new DNS key by using the create dns key command.

      For more information about creating a DNS key, including an example, see Creating DNS Keys for a Zone.

    • Publish the new key in the zone by using the add dns key command.

      For more information about publishing the key in the zone, including an example, see Publishing a DNS Key in a Zone.

    • Sign the zone with the new key by using the sign dns zone command.

      For more information about signing a zone, including examples, see Signing and Unsigning a DNS Zone.

  • Stage 3: DNSKEY Removal. When the RRSIGs that were generated by the old DNS key expire, the old DNS key is removed from the zone.

    Example

    The old DNS key example.com.zsk1 is removed from the example.com zone.

    NetScaler commands

    On the ADC, you remove the old DNS key by using the rm dns key command.

    For more information about removing a key from a zone, including an example, see Removing a DNS Key.