preetam shivaram wrote:
I have got a very simple idea in mind that i want to try out. Say i have a
browser, chrome for instance, and i want to search for the ip of the domain
name, say `www.google.com`. I use windows 7 and i have set the dns lookup
properties to manual and have given the address `127.0.0.1` where my server
(written in Python) is running. I started my server and i could see the dns
query like this:
It seems to me that you want to learn how to write your own DNS caching
server. To do that, you have to understand the DNS protocol. Start with
the Wikipedia article:
http://en.wikipedia.org/wiki/Domain_Name_System
We probably can't help you here, this is a list for learning Python, not
DNS. You might have more luck on the main Python list,
<python-l...@python.com> or news group <comp.lang.python> But generally,
I would expect they'll give you the same advice I am giving: google is
your friend.
Search for "python DNS server" and you will find information that may be
useful to you.
More comments below:
WAITING FOR CONNECTION.........
.........recieved from : ('127.0.0.1', 59339)
"'~\\x17\\x01\\x00\\x00\\x01\\x00\\x00\\x00\\x00\\x00\\x00\\x03www\\x06google\\x02co\\x02in\\x00\\x00\\x01\\x00\\x01'"
The `waiting for connection` and the `received from` is from my server. How
do i get a breakdown form(a human readable form) of this message??
Define "human readable form".
The data you get includes binary bytes, that is, you are getting:
tilde
hex byte 17
hex byte 01
null byte
null byte
hex byte 01
etc.
How would you like the string to be displayed, if not with escaped hex
codes?
If you just print the string, the binary bytes will probably disappear
because your terminal doesn't show them. You can convert to human
readable form with escaped binary bytes using repr() like this:
>>> print s # non-printable characters don't print
~wwwgooglecoin
>>> print repr(s)
'~\x17\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x03www\x06google\x02co\x02in\x00\x00\x01\x00\x01'
You could also try a hex dump, there are many recipes on the Internet.
Here's the first one I tried:
http://code.activestate.com/recipes/142812-hex-dumper/
>>> print(dump(s))
0000 7E 17 01 00 00 01 00 00 ~.......
0008 00 00 00 00 03 77 77 77 .....www
0010 06 67 6F 6F 67 6C 65 02 .google.
0018 63 6F 02 69 6E 00 00 01 co.in...
0020 00 01 ..
--
Steven
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