Computer is sending duplicate packets

#1
Hi all.

I'm having a weird issue with my network connection:

When sniffing my connection using wireshark I'm seeing a ton of duplicate packets incoming and outgoing. To check the issue I've filtered ICMP packets and ran a ping to 8.8.8.8.

What I'm seeing are 4 request packets leaving my NIC with decreasing TTL from 128 to 125 and afterward 4 replies arriving, so i suspect the issue is within my computer.

I've tried multiple searches both with Google and inside forums with no luck finding an answer.
I have no clue to what might be the problem and my only though is maybe the packet rotates 3 times because of the routing table and each time another is sent out (thus the decreasing TTL).
Checked the routing table and the only route conforming with the said destination is the default one so this is not the problem.

Has anyone ever encountered this problem?

OS is WIN7x64, hardware - 2 NICs with only 1 connected to a switch, then a cable modem. (the other NIC is disconnected)
 


patcooke

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#2
A standard ping will always issue four packets and receive four replies by default.
 


#3
I'm referring to the same packet. with same ID sent 4 times with decreasing TTL:
e.g.
running ping -n 1 8.8.8.8 (run only 1 count)
results in:


*Note the same sequence number for all packets
 


patcooke

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#4
Sorry - just seen the -n 1 parameter in your command - I'll check that out.
 


patcooke

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#5
It seems the -n parameter is not being recognise - try something more than 4 and see if that is executed correctly.
 


#6
patcooke, you misunderstood me. These 4 packets are from a single ping request (-n 1)
this is what happens when I do -n 2:



notice the single ping command executed 2 ping packets and received 2, however in the sniffer you see 8 outgoing packets and 8 incoming.

This is not just an issue with PING as I've stated, as it happens with other types of packets aswell:


notice how the program states the packets being DUPs AND have the same SEQUENCE number
 


patcooke

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#7
Ok. And it seems the number of duplicates is always 3 from the small sample you've shown - is it always?
 


#8
Yes. always I see 1 packet and then simultaneously 3 duplicate packets with it.


there are some packets which are "fine" in the way that they are not duplicated but most traffic of IP4 is duped.
 


patcooke

Microsoft MVP
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#9
Always 3 cannot be a coincidence. I'll trydoinf a similar analysis and let you know what I get.
 


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