[142137] in North American Network Operators' Group
Re: So... is it time to do IPv6 day monthy yet?
daemon@ATHENA.MIT.EDU (Jimmy Hess)
Sat Jun 18 11:01:37 2011
In-Reply-To: <20110618093144.46A6E10E6179@drugs.dv.isc.org>
Date: Sat, 18 Jun 2011 10:00:46 -0500
From: Jimmy Hess <mysidia@gmail.com>
To: Mark Andrews <marka@isc.org>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Sat, Jun 18, 2011 at 4:31 AM, Mark Andrews <marka@isc.org> wrote:
> Not really. =A0A AAAA record adds 28 octets (a A record takes 16). =A0Unl=
ess
> you have a lot of name servers most referrals still fall within 512 octet=
s
> additionally most answers also still fall withing 512 octets.
I agree.. not that it should be assumed there is no v6 DNS issue.
With IPv6, the main issue may
be 'firewalls' and 'boxes in the middle' silently munging, eating,
or destroying AAAA responses.
DNSSEC and not AAAA is really the reason to have need for EDNS0 or TRUNC
on validating resolvers. AAAA records should be fine for sane domains.
consider a referral for example.com -> subdomain.example.com with
8 nameservers.
mydomainname.example.com; and assume you get both AAAA and A
additional responses.
Total =3D 402 octets -- still safe; your domain name could be ~100
characters longer and it would still be fine.
Header < 2 (id) + 2 (qr,opcode,aa,tc,rd,ra,z,rcode,qdcount) + 2
(ancount) + 2 (nscount) + 2 (arcount)
=3D 10 octets
Authority Section
ns1.subdomain.example.com. IN NS ns1.subdomain.example.com. <
26name + 2 + 2 + 4 + 2 + 2(pointer) =3D 36 octets
ns2.subdomain.example.com. IN NS ns2.subdomain.example.com. < 4
name + 2(pointer) + 2 + 2 + 4 + 2 +2(pointer) =3D 18 octets
ns3.subdomain.example.com. IN NS ns3.subdomain.example.com. < 4
name + 2 + 2 + 2 + 4 + 2 + 2 =3D 18 octets
ns4.subdomain.example.com. IN NS ns4.subdomain.example.com. < 18 octet=
s
ns5.subdomain.example.com. IN NS ns5.subdomain.example.com. < 18 octet=
s
ns6.subdomain.example.com. IN NS ns6.subdomain.example.com. < 18 octet=
s
ns7.subdomain.example.com. IN NS ns7.subdomain.example.com. < 18 octet=
s
ns8.subdomain.example.com. IN NS ns8.subdomain.example.com. < 18 octet=
s
Additional Section
ns1.subdomain.example.com. IN AAAA 2001:DB8::0 < 2(pointer)
+4TTL+2RDLENGTH+16RDATA =3D 24 octets
ns2.subdomain.example.com. IN AAAA 2001:DB8::1 < 24 octets
ns3.subdomain.example.com. IN AAAA 2001:DB8::2 < 24 octets
ns4.subdomain.example.com. IN AAAA 2001:DB8::3 < 24 octets
ns5.subdomain.example.com. IN AAAA 2001:DB8::4 < 24 octets
ns6.subdomain.example.com. IN AAAA 2001:DB8::5 < 24 octets
ns7.subdomain.example.com. IN AAAA 2001:DB8::6 < 24 octets
ns8.subdomain.example.com. IN AAAA 2001:DB8::7 < 24 octets
ns1.subdomain.example.com. IN A 192.0.0.0.1 < 2(pointer)
+4TTL+2RDLENGTH+4RDATA =3D 12 octets
ns2.subdomain.example.com. IN A 192.0.0.0.1 < 12 octets
ns3subdomain.example.com. IN A 192.0.0.0.1 < 12 octets
ns4.subdomain.example.com. IN A 192.0.0.0.1 < 12 octets
Total =3D 402 octets -- still safe; your domain name could be ~100
characters longer and it would still be fine.
--
-JH
