Below is the packet capture for a small segment of the application which is getting timed out while the connection is established.
It starts with TCP Previous segment not captured, to TCP Out-of-order and leading to TCP Dup ACK. Below is the format.
72 53.967071 Service B Service A TCP 66 44520 → 443 [ACK] Seq=3414 Ack=15055 Win=64308 Len=0 TSval=3811170183 TSecr=1585795827
73 54.223866 Service A Service B TCP 116 [TCP Previous segment not captured] 443 → 44520 [PSH, ACK] Seq=16453 Ack=3414 Win=7643 Len=50 TSval=1585796084 TSecr=3811170183 [TCP segment of a reassembled PDU]
74 54.223903 Service A Service B TCP 166 [TCP Previous segment not captured] 443 → 44520 [PSH, ACK] Seq=19299 Ack=3414 Win=7643 Len=100 TSval=1585796084 TSecr=3811170183 [TCP segment of a reassembled PDU]
74 54.223903 Service A Service B TCP 166 [TCP Previous segment not captured] 443 → 44520 [PSH, ACK] Seq=19299 Ack=3414 Win=7643 Len=100 TSval=1585796084 TSecr=3811170183 [TCP segment of a reassembled PDU]
75 54.223909 Service A Service B TCP 1464 [TCP Out-Of-Order] 443 → 44520 [ACK] Seq=15055 Ack=3414 Win=7643 Len=1398 TSval=1585796084 TSecr=3811170183 [TCP segment of a reassembled PDU]
76 54.223916 Service A Service B TCP 2862 [TCP Out-Of-Order] 443 → 44520 [ACK] Seq=16503 Ack=3414 Win=7643 Len=2796 TSval=1585796084 TSecr=3811170183 [TCP segment of a reassembled PDU]
77 54.223923 Service A Service B TLSv1.2 2495 Application Data [TCP segment of a reassembled PDU]
78 54.223983 Service B Service A TCP 78 [TCP Dup ACK 72#1] 44520 → 443 [ACK] Seq=3414 Ack=15055 Win=64308 Len=0 TSval=3811170440 TSecr=1585795827 SLE=16453 SRE=16503
79 54.223994 Service B Service A TCP 86 [TCP Dup ACK 72#2] 44520 → 443 [ACK] Seq=3414 Ack=15055 Win=64308 Len=0 TSval=3811170440 TSecr=1585795827 SLE=19299 SRE=19399 SLE=16453 SRE=16503
80 54.223996 Service B Service A TCP 78 44520 → 443 [ACK] Seq=3414 Ack=16503 Win=64308 Len=0 TSval=3811170440 TSecr=1585796084 SLE=19299 SRE=19399
81 54.223998 Service B Service A TCP 66 44520 → 443 [ACK] Seq=3414 Ack=19399 Win=64308 Len=0 TSval=3811170440 TSecr=1585796084
82 54.224001 Service B Service A TCP 66 44520 → 443 [ACK] Seq=3414 Ack=21828 Win=64308 Len=0 TSval=3811170440 TSecr=1585796084
83 54.480720 Service A Service B TCP 116 [TCP Previous segment not captured] 443 → 44520 [PSH, ACK] Seq=23226 Ack=3414 Win=7643 Len=50 TSval=1585796341 TSecr=3811170440 [TCP segment of a reassembled PDU]
84 54.480730 Service A Service B TCP 1464 [TCP Out-Of-Order] 443 → 44520 [PSH, ACK] Seq=21828 Ack=3414 Win=7643 Len=1398 TSval=1585796341 TSecr=3811170440 [TCP segment of a reassembled PDU]
85 54.480733 Service A Service B TCP 116 [TCP Previous segment not captured] 443 → 44520 [PSH, ACK] Seq=24674 Ack=3414 Win=7643 Len=50 TSval=1585796341 TSecr=3811170440 [TCP segment of a reassembled PDU]
86 54.480736 Service A Service B TCP 1464 [TCP Out-Of-Order] 443 → 44520 [ACK] Seq=23276 Ack=3414 Win=7643 Len=1398 TSval=1585796341 TSecr=3811170440 [TCP segment of a reassembled PDU]
87 54.480770 Service B Service A TCP 78 [TCP Dup ACK 82#1] 44520 → 443 [ACK] Seq=3414 Ack=21828 Win=64308 Len=0 TSval=3811170697 TSecr=1585796084 SLE=23226 SRE=23276
88 54.480776 Service B Service A TCP 66 44520 → 443 [ACK] Seq=3414 Ack=23276 Win=64308 Len=0 TSval=3811170697 TSecr=1585796341
89 54.480778 Service B Service A TCP 78 [TCP Dup ACK 88#1] 44520 → 443 [ACK] Seq=3414 Ack=23276 Win=64308 Len=0 TSval=3811170697 TSecr=1585796341 SLE=24674 SRE=24724
90 54.480780 Service B Service A TCP 66 44520 → 443 [ACK] Seq=3414 Ack=24724 Win=64308 Len=0 TSval=3811170697 TSecr=1585796341
Can you explain the this behavior?
Once the packets fall in place, the below is observed ending with a connection reset.
96 54.480923 Service B Service A TCP 66 44520 → 443 [ACK] Seq=3414 Ack=30049 Win=64308 Len=0 TSval=3811170697 TSecr=1585796341
97 54.737495 Service A Service B TCP 145 [TCP Previous segment not captured] 443 → 44520 [PSH, ACK] Seq=31447 Ack=3414 Win=7643 Len=79 TSval=1585796597 TSecr=3811170697 [TCP segment of a reassembled PDU] [TCP segment of a reassembled PDU]
98 54.737510 Service A Service B TCP 1464 [TCP Out-Of-Order] 443 → 44520 [PSH, ACK] Seq=30049 Ack=3414 Win=7643 Len=1398 TSval=1585796597 TSecr=3811170697
99 54.737513 Service A Service B TCP 1464 443 → 44520 [PSH, ACK] Seq=31526 Ack=3414 Win=7643 Len=1398 TSval=1585796597 TSecr=3811170697 [TCP segment of a reassembled PDU]
100 54.737569 Service B Service A TCP 78 [TCP Dup ACK 96#1] 44520 → 443 [ACK] Seq=3414 Ack=30049 Win=64308 Len=0 TSval=3811170953 TSecr=1585796341 SLE=31447 SRE=31526
101 54.737575 Service B Service A TCP 66 44520 → 443 [ACK] Seq=3414 Ack=31526 Win=64308 Len=0 TSval=3811170953 TSecr=1585796597
102 54.737578 Service B Service A TCP 66 44520 → 443 [ACK] Seq=3414 Ack=32924 Win=64308 Len=0 TSval=3811170954 TSecr=1585796597
103 54.737582 Service A Service B TCP 2862 443 → 44520 [ACK] Seq=32924 Ack=3414 Win=7643 Len=2796 TSval=1585796597 TSecr=3811170697 [TCP segment of a reassembled PDU]
104 54.737597 Service B Service A TCP 66 44520 → 443 [ACK] Seq=3414 Ack=35720 Win=64308 Len=0 TSval=3811170954 TSecr=1585796597
105 54.737723 Service A Service B TLSv1.2 1778 Application Data, Application Data
106 54.737742 Service B Service A TCP 66 44520 → 443 [ACK] Seq=3414 Ack=37432 Win=64308 Len=0 TSval=3811170954 TSecr=1585796597
108 357.107890 Service A Service B TCP 54 443 → 44520 [RST, ACK] Seq=37432 Ack=3414 Win=0 Len=0
This is causing the application to timeout. It would be helpful if you could explain the behavior so we can identify the cause.
