DNS

1
DNS

• The IPv6 nightmare

2
Currently

• No IPv6 addressed root name servers
• Two standards (AAAA and A6) for forward DNS, with
  two resultant standards for reverse DNS, and no
  current winner
• Messy, long IPv6 addresses and lots of room for
  human error
• ip6.int and ip6.arpa reverse zones

3
Best Practice

• See http//www.tldp.org/HOWTO/LinuxIPv6-HOWTO/hi
  nts-daemons-bind.html
• Forward lookup support
• AAAA
• A6 without chaining, means prefix length set to 0
  
• Reverse lookup support
• Reverse nibble format for zone ip6.int
• Reverse nibble format for zone ip6.arpa

4
Forward (AAAA)

• ORIGIN workshop.aarnet.net.au
• Jdb IN AAAA 20013881c0012022dfffe5bc7ba
• ORIGIN aarnet.net.au
• 6to4.ipv6 IN AAAA 2002c0e7d4051

5
Forward (A6)
6
Reverse ip6.int ip6.arpa

• Same entry but different ORIGIN
• ORIGIN 1.8.8.3.0.1.0.0.2.ip6.int
• a.b.7.c.b.5.e.f.f.f.d.2.2.0.2.0.1.0.0.0.0.0.c
  400 IN PTR jdb.workshop.aarnet.net.au
  .

7
Reverse ip6.arpa (chaining)
8
/etc/named.conf

• acl "zonetransfer"
• 202.6.112.5 // timtam.aarnet.edu.au
• // real secondary for IPv6 stuff
• 192.231.212.5 // dns.ipv6.aarnet.net.au
• 2001388030002/64 // dns.ipv6.aarnet.net.au
• ffff192.231.212.5 // dns.ipv6.aarnet.net.au
• 192.94.209.66 // server66.rno.workshop.aarnet.ne
  t.au
• ffff192.94.209.66 // server66.rno.workshop.aa
  rnet.net.au
• acl "trusted"
• localhost
• zonetransfer
• 1/128

9
/etc/named.conf

• options
• allow-query trusted
• allow-transfer zonetransfer
• listen-on-v6 any
• query-source-v6 address 2001388030002 port
  53
• transfer-source-v6 2001388030002
• notify-source-v6 2001388030002
• / reverse IPv6 localhost /
• zone "0.0.0.0.0.0.0.0.ip6.int"
• type master
• file "0.0.0.0.0.0.0.0.ip6.int"
• allow-update none
• allow-transfer zonetransfer
• allow-query any

10
/etc/named.conf

• / AAAA reverse IPv6 block 0 of 20010388/35 /
• zone "0.8.8.3.0.1.0.0.2.ip6.int"
• type master
• file "0.8.8.3.0.1.0.0.2.ip6.int"
• allow-update none
• allow-transfer zonetransfer
• allow-query any
• / AAAA reverse IPv6 block 1 of 20010388/35 /
• zone "1.8.8.3.0.1.0.0.2.ip6.int"
• type master
• file "1.8.8.3.0.1.0.0.2.ip6.int"
• allow-update none
• allow-transfer zonetransfer
• allow-query any

11
/etc/named.conf

• / A6 reverse IPv6 block 0 of 20010388/35 /
• zone "0.8.8.3.0.1.0.0.2.ip6.arpa"
• type master
• file "0.8.8.3.0.1.0.0.2.ip6.arpa"
• allow-update none
• allow-transfer zonetransfer
• allow-query any
• / A6 reverse IPv6 block 1 of 20010388/35 /
• zone "1.8.8.3.0.1.0.0.2.ip6.arpa"
• type master
• file "1.8.8.3.0.1.0.0.2.ip6.arpa"
• allow-update none
• allow-transfer zonetransfer
• allow-query any

12
IPv6 localhost

• File /var/named/0.0.0.0.0.0.0.0.ip6.int
• _at_ 86400 IN SOA
  ipv6.broadway.aarnet.net.au. root.ipv6.broadway.aa
  rnet.net.au. (
• 2002061400 serial
• 3H refresh
• 15M retry
• 1W expiry
• 1D ) minimum
• 86400 IN NS
  ipv6.broadway.aarnet.net.au
• 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0 86400
  IN PTR ipv6-localhost.
• 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0 86400
  IN PTR ipv6-loopback.