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Duplicate packets in ping

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  Duplicate packets in ping "homer" <2556invalid@webuse.net> - 2011-09-15 19:53 +0000
    Re: Duplicate packets in ping Robert <rkarlsson@gmail.com> - 2011-09-16 02:58 -0700
    Re: Duplicate packets in ping Karthik Bharadwaj <kbforfb@yahoo.com> - 2011-09-16 15:23 -0600

#589 — Duplicate packets in ping

I was pinging some host from my computer connected to a wireless
network, and I noticed this:

64 bytes from 8.8.8.8: icmp_req=61 ttl=52 time=73.3 ms
64 bytes from 8.8.8.8: icmp_req=62 ttl=52 time=74.7 ms
64 bytes from 8.8.8.8: icmp_req=63 ttl=52 time=76.3 ms
64 bytes from 8.8.8.8: icmp_req=63 ttl=52 time=76.8 ms (DUP!)
64 bytes from 8.8.8.8: icmp_req=63 ttl=52 time=77.4 ms (DUP!)
64 bytes from 8.8.8.8: icmp_req=63 ttl=52 time=78.0 ms (DUP!)
64 bytes from 8.8.8.8: icmp_req=64 ttl=52 time=71.1 ms
64 bytes from 8.8.8.8: icmp_req=65 ttl=52 time=75.2 ms
64 bytes from 8.8.8.8: icmp_req=66 ttl=52 time=71.0 ms
64 bytes from 8.8.8.8: icmp_req=67 ttl=52 time=71.0 ms
64 bytes from 8.8.8.8: icmp_req=68 ttl=52 time=78.8 ms
64 bytes from 8.8.8.8: icmp_req=68 ttl=52 time=82.2 ms (DUP!)
64 bytes from 8.8.8.8: icmp_req=69 ttl=52 time=83.9 ms
64 bytes from 8.8.8.8: icmp_req=70 ttl=52 time=73.7 ms
64 bytes from 8.8.8.8: icmp_req=72 ttl=52 time=72.0 ms
64 bytes from 8.8.8.8: icmp_req=73 ttl=52 time=71.2 ms
64 bytes from 8.8.8.8: icmp_req=74 ttl=52 time=72.4 ms
64 bytes from 8.8.8.8: icmp_req=76 ttl=52 time=76.0 ms
64 bytes from 8.8.8.8: icmp_req=77 ttl=52 time=83.3 ms
64 bytes from 8.8.8.8: icmp_req=77 ttl=52 time=84.3 ms (DUP!)
64 bytes from 8.8.8.8: icmp_req=77 ttl=52 time=85.6 ms (DUP!)
64 bytes from 8.8.8.8: icmp_req=78 ttl=52 time=77.1 ms

Now my question is: even with a dodgy network connection, or one with
high latency, how is it possible that duplicate packets appear in ICMP?
My understanding of ICMP echo request/reply is that neither party ever
tries to resend a packet (and, I suppose, none of the intermediate
dvices). So while I understand how packets can be _missing_, where may
those duplicates be coming from? Thanks,

Posted using www.webuse.net 

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#590

On Sep 15, 8:53 pm, "homer" <2556inva...@webuse.net> wrote:
> I was pinging some host from my computer connected to a wireless
> network, and I noticed this:
>
> 64 bytes from 8.8.8.8: icmp_req=61 ttl=52 time=73.3 ms
> 64 bytes from 8.8.8.8: icmp_req=62 ttl=52 time=74.7 ms
> 64 bytes from 8.8.8.8: icmp_req=63 ttl=52 time=76.3 ms
> 64 bytes from 8.8.8.8: icmp_req=63 ttl=52 time=76.8 ms (DUP!)
> 64 bytes from 8.8.8.8: icmp_req=63 ttl=52 time=77.4 ms (DUP!)
> 64 bytes from 8.8.8.8: icmp_req=63 ttl=52 time=78.0 ms (DUP!)
> 64 bytes from 8.8.8.8: icmp_req=64 ttl=52 time=71.1 ms
> 64 bytes from 8.8.8.8: icmp_req=65 ttl=52 time=75.2 ms
> 64 bytes from 8.8.8.8: icmp_req=66 ttl=52 time=71.0 ms
> 64 bytes from 8.8.8.8: icmp_req=67 ttl=52 time=71.0 ms
> 64 bytes from 8.8.8.8: icmp_req=68 ttl=52 time=78.8 ms
> 64 bytes from 8.8.8.8: icmp_req=68 ttl=52 time=82.2 ms (DUP!)
> 64 bytes from 8.8.8.8: icmp_req=69 ttl=52 time=83.9 ms
> 64 bytes from 8.8.8.8: icmp_req=70 ttl=52 time=73.7 ms
> 64 bytes from 8.8.8.8: icmp_req=72 ttl=52 time=72.0 ms
> 64 bytes from 8.8.8.8: icmp_req=73 ttl=52 time=71.2 ms
> 64 bytes from 8.8.8.8: icmp_req=74 ttl=52 time=72.4 ms
> 64 bytes from 8.8.8.8: icmp_req=76 ttl=52 time=76.0 ms
> 64 bytes from 8.8.8.8: icmp_req=77 ttl=52 time=83.3 ms
> 64 bytes from 8.8.8.8: icmp_req=77 ttl=52 time=84.3 ms (DUP!)
> 64 bytes from 8.8.8.8: icmp_req=77 ttl=52 time=85.6 ms (DUP!)
> 64 bytes from 8.8.8.8: icmp_req=78 ttl=52 time=77.1 ms
>
> Now my question is: even with a dodgy network connection, or one with
> high latency, how is it possible that duplicate packets appear in ICMP?
> My understanding of ICMP echo request/reply is that neither party ever
> tries to resend a packet (and, I suppose, none of the intermediate
> dvices). So while I understand how packets can be _missing_, where may
> those duplicates be coming from? Thanks,
>
> Posted usingwww.webuse.net

Check if 2 hosts has the same IP which you are pinging. Around table
is a good place to start.

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#591

On 9/15/2011 1:53 PM, homer wrote:
> I was pinging some host from my computer connected to a wireless
> network, and I noticed this:
>
> 64 bytes from 8.8.8.8: icmp_req=61 ttl=52 time=73.3 ms
> 64 bytes from 8.8.8.8: icmp_req=62 ttl=52 time=74.7 ms
> 64 bytes from 8.8.8.8: icmp_req=63 ttl=52 time=76.3 ms
> 64 bytes from 8.8.8.8: icmp_req=63 ttl=52 time=76.8 ms (DUP!)
> 64 bytes from 8.8.8.8: icmp_req=63 ttl=52 time=77.4 ms (DUP!)
> 64 bytes from 8.8.8.8: icmp_req=63 ttl=52 time=78.0 ms (DUP!)
> 64 bytes from 8.8.8.8: icmp_req=64 ttl=52 time=71.1 ms
> 64 bytes from 8.8.8.8: icmp_req=65 ttl=52 time=75.2 ms
> 64 bytes from 8.8.8.8: icmp_req=66 ttl=52 time=71.0 ms
> 64 bytes from 8.8.8.8: icmp_req=67 ttl=52 time=71.0 ms
> 64 bytes from 8.8.8.8: icmp_req=68 ttl=52 time=78.8 ms
> 64 bytes from 8.8.8.8: icmp_req=68 ttl=52 time=82.2 ms (DUP!)
> 64 bytes from 8.8.8.8: icmp_req=69 ttl=52 time=83.9 ms
> 64 bytes from 8.8.8.8: icmp_req=70 ttl=52 time=73.7 ms
> 64 bytes from 8.8.8.8: icmp_req=72 ttl=52 time=72.0 ms
> 64 bytes from 8.8.8.8: icmp_req=73 ttl=52 time=71.2 ms
> 64 bytes from 8.8.8.8: icmp_req=74 ttl=52 time=72.4 ms
> 64 bytes from 8.8.8.8: icmp_req=76 ttl=52 time=76.0 ms
> 64 bytes from 8.8.8.8: icmp_req=77 ttl=52 time=83.3 ms
> 64 bytes from 8.8.8.8: icmp_req=77 ttl=52 time=84.3 ms (DUP!)
> 64 bytes from 8.8.8.8: icmp_req=77 ttl=52 time=85.6 ms (DUP!)
> 64 bytes from 8.8.8.8: icmp_req=78 ttl=52 time=77.1 ms
>
> Now my question is: even with a dodgy network connection, or one with
> high latency, how is it possible that duplicate packets appear in ICMP?
> My understanding of ICMP echo request/reply is that neither party ever
> tries to resend a packet (and, I suppose, none of the intermediate
> dvices). So while I understand how packets can be _missing_, where may
> those duplicates be coming from? Thanks,
>
> Posted using www.webuse.net

There is a possibility of a bug in the firmware.. This could be a driver 
issue.

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