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syslog
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Question from a test

Fri Jun 20, 2014 10:50 am

Hi all,

I got a question from a test and wanted your expert help.

Based on the following Diagram:
Image

Let's assume R1 and R2 are doing NAT and A1 want to contact D1 (one direction).
I presented the following packet flow:

SRC: 192.168.1.1
DST: 192.168.1.254

SRC: 192.168.100.1
DST: 192.168.100.2

SRC: 192.168.4.254
DST: 192.168.4.1

Is it correct?

Regards,
Syslog

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ristau5741
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Re: Question from a test

Fri Jun 20, 2014 12:03 pm

SRC: 192.168.1.1
DST: 192.168.1.254

host would hit the network deafult gateway first most likely on the router, maybe just the drawing is bad.
But src addresses never change. otherwise the destination wouldn't know how to get traffic back to the source.
and the destination wouldn't change, would always be the destination hosts. with a destination of 192.168.1.254, that's as far as the packet would go.

at layer 2, with MAC addresses, for the most part what you write is true.

edit: wait! what's being natted?
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matgar
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Re: Question from a test

Thu Jun 26, 2014 9:36 am

First: by flow. do you mean the src and dst ip found in the ip header?
Second: where is this "flow" examined?

With some creative NAT/PAT you could get all 3 answers to be "right" depending on where you look at the packet.
With that said I feel that option 2 is probably the expected answer. Since normal internet behaviour would have R1 and R2 to NAT the inside host to their outside interface IP.

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deanwebb
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Re: Question from a test

Thu Jun 26, 2014 9:39 am

ristau5741 wrote:
edit: wait! what's being natted?


Edit edit: What test is this you got the question from?
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