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I have some newby questions about dns.
Here are the steps that lead me to those :
C:\Windows\system32>nslookup google.ca
Serveur : p81-004.pixelweb.net
Address: 206.41.81.4
Réponse ne faisant pas autorité :
Nom : google.ca
Addresses: 2607:f8b0:4006:80b::1018
107.161.13.237
107.161.13.241
107.161.13.245
107.161.13.249
107.161.13.251
107.161.13.207
107.161.13.211
107.161.13.215
107.161.13.219
107.161.13.221
107.161.13.222
107.161.13.226
107.161.13.230
107.161.13.234
107.161.13.236
Then
C:\Windows\system32>nslookup 107.161.13.237
Serveur : p81-004.pixelweb.net
Address: 206.41.81.4
Nom : cache.google.com
Address: 107.161.13.237
Note that I got cache.google.com
for any of those addresses.
- My questions are :
- why is that an entire range of ip addresses are associated with only one host name
cache.google.com
, is it related to ssl? - why did
nslookup
omitted some google addresses within the range 207:251 that respond perfectly in my browser? - why is that
https://107.161.13.237
is resolved whereashttps://cache.google.com/
isn't? - why firefox tells me that
https://107.161.13.237
isn't certified connection, while107.161.13.237
alone is?
Thanks a lot for your answers!
Thanks a lot for all those very clear answers (can't vote you up yet, but will asa I have 15crdts). One last question come to mind though with respect to your last sentence : Why http is reachable through direct ip access while it redirects to a https request when accessed through
http://www.google.ca/
? Is is firefox, the operating system (I doubt), the dns server or google server (I doubt too) that operate this redirection? – Jules Randolph – 2014-10-26T15:13:42.637In this case the redirection is done by the server, using a HTTP redirect. A redirection at the DNS layer is not possible. It is possible that the browser redirects, if it detects unencrypted access to a page which is known from earlier visits to be only accessible encrypted, see HSTS.
– Steffen Ullrich – 2014-10-26T15:36:22.083