Packets in One Direction

Packets in One Direction

In some cases, a network trace will appear to be missing half the traffic. You may only see packets from the client or only from the server, but not both.

Frame Time Offset Source IP    Dest IP      Description
----- ----------- ------------ ------------ ---------------------------------------------------------------------------------------------------
6127  116.5776698 10.10.10.10  10.10.10.120 TCP:Flags=......S., SrcPort=60123, DstPort=1433, PayloadLen=0, Seq=4050702293, Ack=0, Win=8192 ( Ne
6129  116.5786458 10.10.10.10  10.10.10.120 TCP:Flags=...A...., SrcPort=60123, DstPort=1433, PayloadLen=0, Seq=4050702294, Ack=4095166897, Win=
6130  116.5786458 10.10.10.10  10.10.10.120 TDS:Prelogin, Version = 7.1 (0x71000001), SPID = 0, PacketID = 0, Flags=...AP..., SrcPort=60123, Ds
6132  116.5835288 10.10.10.10  10.10.10.120 TLS:TLS Rec Layer-1 HandShake: Client Hello. {TLS:328, SSLVersionSelector:327, TDS:326, TCP:325, IP
6134  116.5864588 10.10.10.10  10.10.10.120 TLS:TLS Rec Layer-1 HandShake: Client Key Exchange.; TLS Rec Layer-2 Cipher Change Spec; TLS Rec La
6136  116.5932948 10.10.10.10  10.10.10.120 TLS:TLS Rec Layer-1 SSL Application Data {TLS:328, SSLVersionSelector:327, TDS:326, TCP:325, IPv4:3
6138  116.5991538 10.10.10.10  10.10.10.120 TDS:SQLBatch, Version = 7.1 (0x71000001), SPID = 0, PacketID = 1, Flags=...AP..., SrcPort=60123, Ds
6266  116.8032558 10.10.10.10  10.10.10.120 TCP:Flags=...A...., SrcPort=60123, DstPort=1433, PayloadLen=0, Seq=4050702956, Ack=4095168204, Win=
6362  116.9097008 10.10.10.10  10.10.10.120 TCP:Flags=...A...F, SrcPort=60123, DstPort=1433, PayloadLen=0, Seq=4050702956, Ack=4095168204, Win=
6366  116.9106778 10.10.10.10  10.10.10.120 TCP:Flags=...A...., SrcPort=60123, DstPort=1433, PayloadLen=0, Seq=4050702957, Ack=4095168205, Win=

Even though packets appear to be missing, the conversation appears to be progressing okay.

This is usually due to using a capture filter that filters on SourceAddress or DestinationAddress instead of just Address or on SrcPort or DstPort instead of just Port, e.g.

NMCAP /network * /capture (ipv4.SourceAddress==10.10.10.10 and tcp.dstport==1433) /file FilteredCap.cap

Similar filter keywords exist for WireShark or other capture tools.