DNS Configuration and Management Manual (G06.27+, H06.05+, J06.03+)

BIND 9.x on the NonStop Server
HP DNS Configuration and Management Manual—529432-003
2-16
IPv6 Address Support
The first 48 bits of the prefix in subnet1.v6.hp.com's record-specific data are set to
zero since they are not significant here. These records tell us to look up two A6 records
next, one at hp-res.lab1.net and one at hp.lab2.net.
By following a chain of A6 records, a name server can assemble all 128 bits of the two
inventor.hp.com IPv6 addresses.
Reverse mapping IPv6 addresses involves DNAME records, described in RFC 2672
“Non-Terminal DNS Name Redirection” and bitstring labels, introduced in RFC 2673
“Binary Labels in the Domain Name System.” DNAME records are like wildcard
CNAME records. They substitute one suffix of a domain name with another. For
example, if you had previously used the domain name hpedu.com at HP University
but had since changed to hpuniv.com, you could have replaced the old hpedu.com
zone with this one:
$TTL 1d
@ IN SOA instructor.hpuniv.com root.hpuniv.com. (
2000102300
3h
30m
30d
1h )
IN NS instructor.hpuniv.com.
IN NS developer.hpuniv.com.
IN MX 10 dnscoursewbt.hpuniv.com.
IN DNAME hpuniv.com.
The DNAME record in the hpedu.com zone applies to any domain name that ends in
hpedu.com except hpedu.com itself. Unlike the CNAME record, the DNAME record
can coexist with other record types owned by the same domain name as long as the
records are not CNAME or other DNAME records. However, the owner of the DNAME
record may not have any subdomains.
When the hpedu.com name server receives a query for any domain name that ends
in hpedu.com (for example, courses.hpedu.com) the DNAME record tells the
Note. If a name server appears in a name server (NS) record and owns one or more A6
records, those A6 records should specify all 128 bits of the IPv6 address. This arrangement
helps avoid deadlock problems, where a resolver or name server needs to talk to a remote
name server to resolve part of that name server's IPv6 address.