Re: ICMP packets with two pairs of source and destination ip addresses?

[ronnie sahlberg <ronniesahlberg () gmail com>]

the ip layer appears twice in those packets.

First as IP layer sitting above ETHernet layer
Second as IP layer sitting above ICMP layer

Same thing happens when you tunnel ip over ip



On Wed, Jun 6, 2012 at 8:20 PM, nangergong <nangergong () gmail com> wrote:
> HI, all,
>
>      I used tshark to parse a pcap file with icmp packets,
>                   tshark -r icmp -T fields -e frame.number -e ip.src -e
> ip.dst
>
>      and the results are something like this:
>
> 1    74.125.132.188    138.96.192.56
> 2    74.125.132.188    138.96.192.56
> 3    138.96.192.56,74.125.132.188    74.125.132.188,138.96.192.56
> 4    138.96.192.56,74.125.132.188    74.125.132.188,138.96.192.56
> 5    74.125.132.188    138.96.192.56
> 6    138.96.192.56,74.125.132.188    74.125.132.188,138.96.192.56
> 7    74.125.132.188    138.96.192.56
> 8    138.96.192.56,74.125.132.188    74.125.132.188,138.96.192.56
> 9    74.125.132.188    138.96.192.56
> 10    138.96.192.56,74.125.132.188    74.125.132.188,138.96.192.56
> 11    74.125.132.188    138.96.192.56
> 12    138.96.192.56,74.125.132.188    74.125.132.188,138.96.192.56
>
>
> so , like 3, 4, 6,8,10,12 , there are two src ip addr and dst ip addr
> what is the reason for this? thanks
>
>
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