NetBSD/external/bsd/bind/dist/README.dnssec

			DNSSEC and Dynamic Zones

As of BIND 9.7.0 it is possible to change a dynamic zone from
insecure to secure and back again.  A secure zone can use either
NSEC or NSEC3 chains.

		Converting from insecure to secure

Changing a zone from insecure to secure can be done in two ways:
using a dynamic DNS update, or the "auto-dnssec" zone option.

For either method, you need to configure named so that it can see
the K* files which contain the public and private parts of the keys
that will be used to sign the zone.  These files will have been
generated by dnssec-keygen.  You can do this by placing them in
the key-directory, as specified in named.conf:

	zone example.net {
		type master;
		update-policy local;
		file "dynamic/example.net/example.net";
		key-directory "dynamic/example.net";
	};

If one KSK and one ZSK DNSKEY key have been generated, this configuration
will cause all records in the zone to be signed with the ZSK, and the
DNSKEY RRset to be signed with the KSK as well.  An NSEC chain will be
generated as part of the initial signing process.

		Dynamic DNS update method

To insert the keys via dynamic update:

	% nsupdate
	> ttl 3600
	> update add example.net DNSKEY 256 3 7 AwEAAZn17pUF0KpbPA2c7Gz76Vb18v0teKT3EyAGfBfL8eQ8al35zz3Y I1m/SAQBxIqMfLtIwqWPdgthsu36azGQAX8=
	> update add example.net DNSKEY 257 3 7 AwEAAd/7odU/64o2LGsifbLtQmtO8dFDtTAZXSX2+X3e/UNlq9IHq3Y0 XtC0Iuawl/qkaKVxXe2lo8Ct+dM6UehyCqk=
	> send

While the update request will complete almost immediately, the zone
will not be completely signed until named has had time to walk the
zone and generate the NSEC and RRSIG records.  The NSEC record at the
apex will be added last, to signal that there is a complete NSEC chain.

If you wish to sign using NSEC3 instead of NSEC, you should add an
NSEC3PARAM record to the initial update request.  If you wish the
NSEC3 chain to have the OPTOUT bit set, set it in the flags field
of the NSEC3PARAM record.

	% nsupdate
	> ttl 3600
	> update add example.net DNSKEY 256 3 7 AwEAAZn17pUF0KpbPA2c7Gz76Vb18v0teKT3EyAGfBfL8eQ8al35zz3Y I1m/SAQBxIqMfLtIwqWPdgthsu36azGQAX8=
	> update add example.net DNSKEY 257 3 7 AwEAAd/7odU/64o2LGsifbLtQmtO8dFDtTAZXSX2+X3e/UNlq9IHq3Y0 XtC0Iuawl/qkaKVxXe2lo8Ct+dM6UehyCqk=
	> update add example.net NSEC3PARAM 1 1 100 1234567890
	> send

Again, this update request will complete almost immediately; however,
the record won't show up until named has had a chance to build/remove
the relevant chain.  A private type record will be created to record
the state of the operation (see below for more details), and will be
removed once the operation completes.

While the initial signing and NSEC/NSEC3 chain generation is happening,
other updates are possible as well.

		Fully automatic zone signing

To enable automatic signing, add the "auto-dnssec" option to the zone
statement in named.conf.  "auto-dnssec" has two possible arguments:
"allow" or "maintain".

With "auto-dnssec allow", named can search the key directory for keys
matching the zone, insert them into the zone, and use them to sign the
zone.  It will do so only when it receives an "rndc sign <zonename>"
command.

"auto-dnssec maintain" includes the above functionality, but will also
automatically adjust the zone's DNSKEY records on schedule according to the
keys' timing metadata (see the man pages for dnssec-keygen and
dnssec-settime for more information).  If keys are present in the key
directory the first time the zone is loaded, it will be signed
immediately, without waiting for an "rndc sign" command.  (This
command can still be used for unscheduled key changes, however.)

Using the "auto-dnssec" option requires the zone to be configured to
allow dynamic updates, by adding an "allow-update" or "update-policy"
statement to the zone configuration.  If this has not been done, the
configuration will fail.

		Private-type records

The state of the signing process is signaled by private-type records
(with a default type value of 65534).  When signing is complete, these
records will have a nonzero value for the final octet (for those records
which have a nonzero initial octet).

The private type record format:
If the first octet is non-zero then the record indicates that the zone needs
to be signed with the key matching the record, or that all signatures that
match the record should be removed.

	algorithm (octet 1)
	key id in network order (octet 2 and 3)
	removal flag (octet 4)
	complete flag (octet 5)

Only records flagged as "complete" can be removed via dynamic update.
Attempts to remove other private type records will be silently ignored.

If the first octet is zero (this is a reserved algorithm number
that should never appear in a DNSKEY record) then the record indicates
changes to the NSEC3 chains are in progress.  The rest of the record
contains an NSEC3PARAM record.  The flag field tells what operation
to perform based on the flag bits.

	0x01 OPTOUT
	0x80 CREATE
	0x40 REMOVE
	0x20 NONSEC

		DNSKEY rollovers via UPDATE

It is possible to perform key rollovers via dynamic update.  You need
to add the K* files for the new keys so that named can find them.  You
can then add the new DNSKEY RRs via dynamic update.  Named will then cause
the zone to be signed with the new keys.  When the signing is
complete the private type records will be updated so that the last
octet is non zero.

If this is for a KSK you need to inform the parent and any trust
anchor repositories of the new KSK.

You should then wait for the maximum TTL in the zone before removing the
old DNSKEY.  If it is a KSK that is being updated, you also need to wait
for the DS RRset in the parent to be updated and its TTL to expire.
This ensures that all clients will be able to verify at least one
signature when you remove the old DNSKEY.

The old DNSKEY can be removed via UPDATE.  Take care to specify
the correct key.  Named will clean out any signatures generated by
the old key after the update completes.

		NSEC3PARAM rollovers via UPDATE

Add the new NSEC3PARAM record via dynamic update.  When the new NSEC3 chain
has been generated, the NSEC3PARAM flag field will be zero.  At this
point you can remove the old NSEC3PARAM record.  The old chain will
be removed after the update request completes.

		Converting from NSEC to NSEC3

To do this, you just need to add an NSEC3PARAM record.  When the
conversion is complete, the NSEC chain will have been removed and
the NSEC3PARAM record will have a zero flag field.  The NSEC3 chain
will be generated before the NSEC chain is destroyed.

		Converting from NSEC3 to NSEC

To do this, remove all NSEC3PARAM records with a zero flag field.  The
NSEC chain will be generated before the NSEC3 chain is removed.

		Converting from secure to insecure

To do this, remove all the DNSKEY records.  Any NSEC or NSEC3 chains
will be removed as well, along with associated NSEC3PARAM records.
This will take place after the update request completes.  This
requires the "dnssec-secure-to-insecure" option to be set to "yes"
in named.conf.

		Periodic re-signing

In any secure zone which supports dynamic updates, named will
periodically re-sign RRsets which have not been re-signed as
a result of some update action.  The signature lifetimes will
be adjusted so as to spread the re-sign load over time rather than
all at once.

		NSEC3 and OPTOUT

Named only supports creating new NSEC3 chains where all the NSEC3
records in the zone have the same OPTOUT state.  Named supports
UPDATES to zones where the NSEC3 records in the chain have mixed
OPTOUT state.  Named does not support changing the OPTOUT state of
an individual NSEC3 record, the entire chain needs to be changed if
the OPTOUT state of an individual NSEC3 needs to be changed.