[Chugalug] OT: does chromecast force use of google public dns?

Matt Keys mk6032 at yahoo.com
Mon Sep 9 15:50:02 UTC 2013


I use pfsense as my router/gateway and separate WAP attached as a 
bridge. There's no multicast filtering there or any filtering really -- 
it's just a dumb pass everything wireless bridge. I assigned a dhcp 
static ip mapping for my new chromecast device and created a firewall 
rule in pf to allow all traffic but to also log it. The dhcp server is 
set to dish out primary dns 192.168.1.1, secondary 8.8.8.8, third 
8.8.4.4. I then power up the chromecast and attempt to hitch it to the 
wireless. Chromecast then states that it connected successfully but 
cannot reach the internet. Packet capture shows that it does not hit 
192.168.1.1 at all for dns query to "client3.google.com" and others such 
as ntp.pool.org. It *always* goes to 8.8.8.8 and 8.8.4.4. Sampled 
capture at http://www.mattkeys.net/google/chromecast.cap. Interesting 
that if I nslookup client3.google.com against 192.168.1.1 I get good 
results, but if I nslookup against googles own 8.8.8.8 and 8.8.4.4 I get 
timeout responses.

matt at pud64:~$ nslookup
 > server 192.168.1.1
Default server: 192.168.1.1
Address: 192.168.1.1#53
 > clients3.google.com
Server:        192.168.1.1
Address:    192.168.1.1#53

Non-authoritative answer:
clients3.google.com    canonical name = clients.l.google.com.
Name:    clients.l.google.com
Address: 74.125.137.101
Name:    clients.l.google.com
Address: 74.125.137.102
Name:    clients.l.google.com
Address: 74.125.137.139
Name:    clients.l.google.com
Address: 74.125.137.113
Name:    clients.l.google.com
Address: 74.125.137.138
Name:    clients.l.google.com
Address: 74.125.137.100
 > server 8.8.8.8
Default server: 8.8.8.8
Address: 8.8.8.8#53
 > clients3.google.com
;; connection timed out; no servers could be reached
 > server 8.8.4.4
Default server: 8.8.4.4
Address: 8.8.4.4#53
 > clients3.google.com
;; connection timed out; no servers could be reached
 > exit

I've got a product support email out to Google about it.



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