DNS64 & nslookup

Chuck Swiger cswiger at mac.com
Wed Apr 11 23:40:40 UTC 2018


On Apr 11, 2018, at 4:26 PM, Mark Boolootian <booloo at ucsc.edu> wrote:
>>> As far as I know, a host with on an IPv6 address is only ever
>>> going to perform AAAA lookups.  I'd be very interested to know
>>> if there are cases where that isn't true.
>> 
>> Well, if you run nslookup or dig -t a, you're asking for A records
>> explicitly.
> 
> Ah, true that.  Does nslookup do that by default?

Yes, nslookup has A as the default type.  Here is nslookup handling a AAAA query:

% nslookup -type=aaaa ipv4.l.google.com
Server:		192.168.1.1
Address:	192.168.1.1#53

Non-authoritative answer:
*** Can't find ipv4.l.google.com: No answer

Authoritative answers can be found from:
l.google.com
	origin = ns1.google.com
	mail addr = dns-admin.google.com
	serial = 192521433
	refresh = 900
	retry = 900
	expire = 1800
	minimum = 60

(If DNS64 was in place, I ought to see 74.125.24.x mapped to an IPv6 address instead-- something like 64:ff9b::74.125.24.x.)

Regards,
-- 
-Chuck



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