[Pdns-users] CNAME to other nameserver, what should a recursor do?

Mon Dec 12 12:17:04 UTC 2011

Hi,

I'm having problems reaching webmail.deictvereniging.nl when using
pdns-recursor 3.3-1 and 3.3.1

my pdns-recursor 3.3-1 says:
dig +short webmail.deictvereniging.nl @.....
webmail.prioserve.net.

my pdns-recursor 3.3.1 also says:
dig +short webmail.deictvereniging.nl @.....
webmail.prioserve.net.

I'm NOT having problems reaching webmail.deictvereniging.nl when using
unbound 1.4.5 and pdns-recursor 3.1.7.2

my unbound 1.4.5 recursor says:
dig +short webmail.deictvereniging.nl @.....
webmail.prioserve.net.
91.216.113.22

my pdns-recursor 3.1.7.2 also says:
dig +short webmail.deictvereniging.nl @.....
webmail.prioserve.net.
91.216.113.22
(well, it omits the ip-address the first time around, but if I ask again it
provides the ip-address)

Config stays the same, the config from the package 3.3-1, with the
'allow-from-file' and 'local-address' settings adjusted to my situation,
nothing else changed.

What is the recursor supposed to do? And is it possible to make 3.3.1 and 3.3-1
exhibit the 3.1.7.2 and unbound 1.4.5 behaviour?

Here some TCPdumps to show that 3.1.7.2 does some extra work on my query and
3.3.1 doesn't:

(these are examples, I tried often)

If I tcpdump 3.1.7.2 (dig +short webmail.deictvereniging.nl @..... twice)
(X.X.X.X = client-pc, Y.Y.Y.Y = recursor)

14:00:09.051223 IP X.X.X.X.12764 > Y.Y.Y.Y.53: 14698+ A? webmail.deictvereniging.nl. (44)
14:00:09.051508 IP Y.Y.Y.Y.11849 > 192.33.4.12.53: 5902 A? webmail.deictvereniging.nl. (44)
14:00:09.066211 IP 192.33.4.12.53 > Y.Y.Y.Y.11849: 5902- 0/7/14 (511)
14:00:09.066432 IP Y.Y.Y.Y.30603 > 193.176.144.2.53: 47726 A? webmail.deictvereniging.nl. (44)
14:00:09.075990 IP 193.176.144.2.53 > Y.Y.Y.Y.30603: 47726- 0/3/3 (166)
14:00:09.076117 IP Y.Y.Y.Y.6159 > 92.60.122.242.53: 60745 A? webmail.deictvereniging.nl. (44)
14:00:09.096191 IP 92.60.122.242.53 > Y.Y.Y.Y.6159: 60745 NXDomain*- 1/1/0 (142)
14:00:09.096320 IP Y.Y.Y.Y.53 > X.X.X.X.12764: 14698 NXDomain 1/1/0 (142)

14:00:15.698623 IP X.X.X.X.12817 > Y.Y.Y.Y.53: 10678+ A? webmail.deictvereniging.nl. (44)
14:00:15.698888 IP Y.Y.Y.Y.4343 > 199.7.83.42.53: 33926 A? webmail.prioserve.net. (39)
14:00:15.705678 IP 199.7.83.42.53 > Y.Y.Y.Y.4343: 33926- 0/13/14 (496)
14:00:15.705905 IP Y.Y.Y.Y.63586 > 192.12.94.30.53: 15614 A? webmail.prioserve.net. (39)
14:00:15.723364 IP 192.12.94.30.53 > Y.Y.Y.Y.63586: 15614- 0/3/2 (137)
14:00:15.723522 IP Y.Y.Y.Y.34704 > 213.239.134.20.53: 39014 A? webmail.prioserve.net. (39)
14:00:15.730529 IP 213.239.134.20.53 > Y.Y.Y.Y.34704: 39014*- 1/3/3 (169)
14:00:15.730657 IP Y.Y.Y.Y.53 > X.X.X.X.12817: 10678 2/0/0[|domain]

If I tcpdump 3.3.1 (dig +short webmail.deictvereniging.nl @..... twice)
(X.X.X.X = client-pc, Y.Y.Y.Y = recursor)

14:04:38.192952 IP X.X.X.X.16134 > Y.Y.Y.Y.53: 55042+ A? webmail.deictvereniging.nl. (44)
14:04:38.193260 IP Y.Y.Y.Y.50331 > 192.203.230.10.53: 14099 A? webmail.deictvereniging.nl. (44)
14:04:38.355543 IP 192.203.230.10.53 > Y.Y.Y.Y.50331: 14099- 0/7/14 (511)
14:04:38.355946 IP Y.Y.Y.Y.11949 > 213.154.241.28.53: 20304 A? webmail.deictvereniging.nl. (44)
14:04:38.363475 IP 213.154.241.28.53 > Y.Y.Y.Y.11949: 20304- 0/3/3 (166)
14:04:38.363589 IP Y.Y.Y.Y.13148 > 174.143.144.174.53: 56654 A? webmail.deictvereniging.nl. (44)
14:04:38.489184 IP 174.143.144.174.53 > Y.Y.Y.Y.13148: 56654 NXDomain*- 1/1/0 (142)
14:04:38.489394 IP Y.Y.Y.Y.53 > X.X.X.X.16134: 55042 NXDomain 1/1/0 (142)

14:04:48.440018 IP X.X.X.X.16298 > Y.Y.Y.Y.53: 41520+ A? webmail.deictvereniging.nl. (44)
14:04:48.440304 IP Y.Y.Y.Y.2957 > 192.112.36.4.53: 50327 A? webmail.deictvereniging.nl. (44)
14:04:48.476429 IP 192.112.36.4.53 > Y.Y.Y.Y.2957: 50327- 0/7/14 (511)
14:04:48.476851 IP Y.Y.Y.Y.23507 > 193.176.144.2.53: 23778 A? webmail.deictvereniging.nl. (44)
14:04:48.486065 IP 193.176.144.2.53 > Y.Y.Y.Y.23507: 23778- 0/3/3 (166)
14:04:48.486225 IP Y.Y.Y.Y.5951 > 174.143.144.174.53: 50521 A? webmail.deictvereniging.nl. (44)
14:04:48.607337 IP 174.143.144.174.53 > Y.Y.Y.Y.5951: 50521 NXDomain*- 1/1/0 (142)
14:04:48.607511 IP Y.Y.Y.Y.53 > X.X.X.X.16298: 41520 NXDomain 1/1/0 (142)

Grtz,
-- Niek
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