All Packets Duplicated

In some cases, you may notice that all the packets in a network trace are duplicated.

Frame Offset      Source IP   Dest IP     Description
----- ----------- ----------- ----------- -----------------------------------------------------------------------------------------------
2631  140.1400414 10.10.10.10 10.10.10.22 TDS:RPCRequest, Version = 7.300000(No version information available, using the default version)
2632  140.1400424 10.10.10.10 10.10.10.22 TCP:[ReTransmit #2631]Flags=...A...., SrcPort=37768, DstPort=1433, PayloadLen=1460, Seq=9357361
2633  140.1400539 10.10.10.22 10.10.10.10 TCP: [Bad CheckSum]Flags=...A...., SrcPort=1433, DstPort=37768, PayloadLen=0, Seq=907541922, Ac
2634  140.1400545 10.10.10.22 10.10.10.10 TCP:[Dup Ack #2633] [Bad CheckSum]Flags=...A...., SrcPort=1433, DstPort=37768, PayloadLen=0, Se
2637  140.1401051 10.10.10.10 10.10.10.22 TDS:SQLBatch, Version = 7.300000(No version information available, using the default version), 
2638  140.1401061 10.10.10.10 10.10.10.22 TCP:[ReTransmit #2637]Flags=...AP..., SrcPort=36816, DstPort=1433, PayloadLen=90, Seq=101311560
2639  140.1401278 10.10.10.22 10.10.10.10 TDS:Response, Version = 7.300000(No version information available, using the default version), 
2640  140.1401294 10.10.10.22 10.10.10.10 TCP:[ReTransmit #2639] [Bad CheckSum]Flags=...AP..., SrcPort=1433, DstPort=37768, PayloadLen=74
2641  140.1401518 10.10.10.22 10.10.10.10 TDS:Response, Version = 7.300000(No version information available, using the default version), 
2642  140.1401531 10.10.10.22 10.10.10.10 TCP:[ReTransmit #2641] [Bad CheckSum]Flags=...AP..., SrcPort=1433, DstPort=36816, PayloadLen=48
2643  140.1402283 10.10.10.22 10.10.10.10 TDS:Response, Version = 7.300000(No version information available, using the default version), 
2644  140.1402302 10.10.10.22 10.10.10.10 TCP:[ReTransmit #2643] [Bad CheckSum]Flags=...AP..., SrcPort=1433, DstPort=47962, PayloadLen=16
2659  140.1408609 10.10.10.10 10.10.10.22 TDS:SQLBatch, Version = 7.300000(No version information available, using the default version), 
2660  140.1408616 10.10.10.10 10.10.10.22 TCP:[ReTransmit #2659]Flags=...AP..., SrcPort=37768, DstPort=1433, PayloadLen=90, Seq=935738026
2661  140.1408731 10.10.10.10 10.10.10.22 TDS:SQLBatch, Version = 7.300000(No version information available, using the default version), 
2662  140.1408747 10.10.10.10 10.10.10.22 TCP:[ReTransmit #2661]Flags=...AP..., SrcPort=38080, DstPort=1433, PayloadLen=46, Seq=372244528
2663  140.1409064 10.10.10.22 10.10.10.10 TDS:Response, Version = 7.300000(No version information available, using the default version), 
2664  140.1409077 10.10.10.22 10.10.10.10 TCP:[ReTransmit #2663] [Bad CheckSum]Flags=...AP..., SrcPort=1433, DstPort=37768, PayloadLen=48
2665  140.1409720 10.10.10.22 10.10.10.10 TDS:Response, Version = 7.300000(No version information available, using the default version), 
2666  140.1409733 10.10.10.22 10.10.10.10 TCP:[ReTransmit #2665] [Bad CheckSum]Flags=...AP..., SrcPort=1433, DstPort=38080, PayloadLen=37
2671  140.1410158 10.10.10.10 10.10.10.22 TDS:SQLBatch, Version = 7.300000(No version information available, using the default version), 
2672  140.1410165 10.10.10.10 10.10.10.22 TCP:[ReTransmit #2671]Flags=...AP..., SrcPort=47962, DstPort=1433, PayloadLen=90, Seq=15608618 
2677  140.1414667 10.10.10.10 10.10.10.22 TCP:Flags=...A...., SrcPort=38080, DstPort=1433, PayloadLen=0, Seq=3722445334, Ack=3471897492, 
2678  140.1414677 10.10.10.10 10.10.10.22 TCP:[Dup Ack #2677]Flags=...A...., SrcPort=38080, DstPort=1433, PayloadLen=0, Seq=3722445334, A
2687  140.1415797 10.10.10.10 10.10.10.22 TDS:SQLBatch, Version = 7.300000(No version information available, using the default version), 
2688  140.1415806 10.10.10.10 10.10.10.22 TCP:[ReTransmit #2687]Flags=...AP..., SrcPort=50706, DstPort=1433, PayloadLen=46, Seq=378432362
2689  140.1416609 10.10.10.10 10.10.10.22 TDS:RPCRequest, Version = 7.300000(No version information available, using the default version)
2690  140.1416619 10.10.10.10 10.10.10.22 TCP:[ReTransmit #2689]Flags=...AP..., SrcPort=38080, DstPort=1433, PayloadLen=431, Seq=37224453
2691  140.1416680 10.10.10.22 10.10.10.10 TDS:Response, Version = 7.300000(No version information available, using the default version), 
2692  140.1416693 10.10.10.22 10.10.10.10 TCP:[ReTransmit #2691] [Bad CheckSum]Flags=...AP..., SrcPort=1433, DstPort=50706, PayloadLen=37
2695  140.1417403 10.10.10.22 10.10.10.10 TDS:Response, Version = 7.300000(No version information available, using the default version), 
2696  140.1417416 10.10.10.22 10.10.10.10 TCP:[ReTransmit #2695] [Bad CheckSum]Flags=...AP..., SrcPort=1433, DstPort=38080, PayloadLen=18

Frame 2632 is a retransmission of 2631, 2634 is a Duplicate Ack of 2633, etc. Every packet is retransmitted once exactly.

This does not indicate a network issue but a capture issue. For example, if capturing the input traffic and the output traffic on a network device and the two captures are merged into one file. Port mirroring and having teamed NIC cards can sometimes show this pattern. Also, capturing at two different levels of the network stack or capturing at a network gateway and getting traffic from both subnets it is connected to.

To correct, try to capture only the input or output traffic, or capture only a single source on the machine rather than all sources.