Eg. http://www.duckdns.org
One doing nslookup for the above named domain on 8.8.8.8, I get a very quick reply. With debug on, here is the reply, point being the response is very quick.
Code: Select all
> www.duckdns.org
Server: google-public-dns-a.google.com
Address: 8.8.8.8
------------
SendRequest(), len 33
HEADER:
opcode = QUERY, id = 2, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0
QUESTIONS:
www.duckdns.org, type = A, class = IN
------------
------------
Got answer (49 bytes):
HEADER:
opcode = QUERY, id = 2, rcode = NOERROR
header flags: response, want recursion, recursion avail.
questions = 1, answers = 1, authority records = 0, additional = 0
QUESTIONS:
www.duckdns.org, type = A, class = IN
ANSWERS:
-> www.duckdns.org
type = A, class = IN, dlen = 4
internet address = 52.24.195.93
ttl = 18 (18 secs)
------------
Non-authoritative answer:
------------
SendRequest(), len 33
HEADER:
opcode = QUERY, id = 3, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0
QUESTIONS:
www.duckdns.org, type = AAAA, class = IN
------------
------------
Got answer (33 bytes):
HEADER:
opcode = QUERY, id = 3, rcode = SERVFAIL
header flags: response, want recursion, recursion avail.
questions = 1, answers = 0, authority records = 0, additional = 0
QUESTIONS:
www.duckdns.org, type = AAAA, class = IN
------------
Name: www.duckdns.org
Address: 52.24.195.93However, when I run the same thing, using the router dns server, there is a significant delay. It does not send a SERVFAIL reply for the AAAA record, so the dns client waits till it times out. Hence, opening http://www.duckdns.org is significantly delayed.
Code: Select all
> www.duckdns.org
Server: [192.168.0.1]
Address: 192.168.0.1
------------
SendRequest(), len 33
HEADER:
opcode = QUERY, id = 5, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0
QUESTIONS:
www.duckdns.org, type = A, class = IN
------------
------------
Got answer (49 bytes):
HEADER:
opcode = QUERY, id = 5, rcode = NOERROR
header flags: response, want recursion, recursion avail.
questions = 1, answers = 1, authority records = 0, additional = 0
QUESTIONS:
www.duckdns.org, type = A, class = IN
ANSWERS:
-> www.duckdns.org
type = A, class = IN, dlen = 4
internet address = 52.24.195.93
ttl = 19 (19 secs)
------------
Non-authoritative answer:
------------
SendRequest(), len 33
HEADER:
opcode = QUERY, id = 6, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0
QUESTIONS:
www.duckdns.org, type = AAAA, class = IN
------------
DNS request timed out.
timeout was 2 seconds.
timeout (2 secs)
SendRequest failed
Name: www.duckdns.org
Address: 52.24.195.93