Sequence numbers from 172.16.98.74 in white on black indicate data that was dropped in the network, as determined by a retransmission from 172.16.98.74. Acknowledgement numbers from 172.16.98.74 in white on black indicate ACKs that were dropped in the network, as determined by a retransmission from 192.168.32.1.
As you can see every other packet from 172.16.98.74 is dropped by the network.
1 IP-192.168.43.1 IP-172.16.98.74 350 "Src=55523 Dst=11015 .AP... S=4139707118 L= 280 A=2970345660 W= 8192" TCP 2 IP-172.16.98.74 IP-192.168.43.1 70 0.061628 "Src=11015 Dst=55523 .A.... S=2970345730 L= 0 A=4139707398 W=32768" TCP 3 IP-192.168.43.1 IP-172.16.98.74 140 4.442807 "Src=55523 Dst=11015 .AP... S=4139707398 L= 70 A=2970345660 W= 8192" TCP 4 IP-172.16.98.74 IP-192.168.43.1 70 0.066472 "Src=11015 Dst=55523 .A.... S=2970345730 L= 0 A=4139707468 W=32768" TCP 6 IP-192.168.43.1 IP-172.16.98.74 140 1.414085 "Src=55523 Dst=11015 .AP... S=4139707398 L= 70 A=2970345660 W= 8192" TCP 7 IP-172.16.98.74 IP-192.168.43.1 70 0.000551 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707468 W=32768" TCP 8 IP-172.16.98.74 IP-192.168.43.1 140 11.298757 "Src=11015 Dst=55523 .AP... S=2970345660 L= 70 A=4139707468 W=32768" TCP 10 IP-192.168.43.1 IP-172.16.98.74 64 34.029950 "Src=55523 Dst=11015 .A.... S=4139707467 L= 1 A=2970345659 W= 8192" TCP 11 IP-172.16.98.74 IP-192.168.43.1 70 0.000538 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707468 W=32768" TCP 12 IP-192.168.43.1 IP-172.16.98.74 140 13.867582 "Src=55523 Dst=11015 .AP... S=4139707468 L= 70 A=2970345660 W= 8192" TCP 13 IP-172.16.98.74 IP-192.168.43.1 70 0.069607 "Src=11015 Dst=55523 .A.... S=2970345730 L= 0 A=4139707538 W=32768" TCP 15 IP-192.168.43.1 IP-172.16.98.74 140 2.844203 "Src=55523 Dst=11015 .AP... S=4139707468 L= 70 A=2970345660 W= 8192" TCP 16 IP-172.16.98.74 IP-192.168.43.1 70 0.000292 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707538 W=32768" TCP 17 IP-172.16.98.74 IP-192.168.43.1 140 9.313404 "Src=11015 Dst=55523 .AP... S=2970345660 L= 70 A=4139707538 W=32768" TCP 19 IP-192.168.43.1 IP-172.16.98.74 64 35.834717 "Src=55523 Dst=11015 .A.... S=4139707537 L= 1 A=2970345659 W= 8192" TCP 20 IP-172.16.98.74 IP-192.168.43.1 70 0.000496 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707538 W=32768" TCP 21 IP-192.168.43.1 IP-172.16.98.74 140 12.614147 "Src=55523 Dst=11015 .AP... S=4139707538 L= 70 A=2970345660 W= 8192" TCP 22 IP-172.16.98.74 IP-192.168.43.1 70 0.068548 "Src=11015 Dst=55523 .A.... S=2970345730 L= 0 A=4139707608 W=32768" TCP 24 IP-192.168.43.1 IP-172.16.98.74 140 5.445152 "Src=55523 Dst=11015 .AP... S=4139707538 L= 70 A=2970345660 W= 8192" TCP 25 IP-172.16.98.74 IP-192.168.43.1 70 0.000396 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707608 W=32768" TCP 26 IP-172.16.98.74 IP-192.168.43.1 140 6.168950 "Src=11015 Dst=55523 .AP... S=2970345660 L= 70 A=4139707608 W=32768" TCP 28 IP-192.168.43.1 IP-172.16.98.74 64 39.631839 "Src=55523 Dst=11015 .A.... S=4139707607 L= 1 A=2970345659 W= 8192" TCP 29 IP-172.16.98.74 IP-192.168.43.1 70 0.000541 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707608 W=32768" TCP 30 IP-192.168.43.1 IP-172.16.98.74 140 9.364319 "Src=55523 Dst=11015 .AP... S=4139707608 L= 70 A=2970345660 W= 8192" TCP 31 IP-172.16.98.74 IP-192.168.43.1 70 0.070426 "Src=11015 Dst=55523 .A.... S=2970345730 L= 0 A=4139707678 W=32768" TCP 33 IP-192.168.43.1 IP-172.16.98.74 140 9.905233 "Src=55523 Dst=11015 .AP... S=4139707608 L= 70 A=2970345660 W= 8192" TCP 34 IP-172.16.98.74 IP-192.168.43.1 70 0.000525 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707678 W=32768" TCP 35 IP-172.16.98.74 IP-192.168.43.1 140 1.137104 "Src=11015 Dst=55523 .AP... S=2970345660 L= 70 A=4139707678 W=32768" TCP 37 IP-192.168.43.1 IP-172.16.98.74 64 45.450462 "Src=55523 Dst=11015 .A.... S=4139707677 L= 1 A=2970345659 W= 8192" TCP 38 IP-172.16.98.74 IP-192.168.43.1 70 0.000434 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707678 W=32768" TCP 39 IP-192.168.43.1 IP-172.16.98.74 140 4.118404 "Src=55523 Dst=11015 .AP... S=4139707678 L= 70 A=2970345660 W= 8192" TCP 40 IP-172.16.98.74 IP-192.168.43.1 70 0.068311 "Src=11015 Dst=55523 .A.... S=2970345730 L= 0 A=4139707748 W=32768" TCP 42 IP-172.16.98.74 IP-192.168.43.1 140 10.473988 "Src=11015 Dst=55523 .AP... S=2970345660 L= 70 A=4139707748 W=32768" TCP 43 IP-192.168.43.1 IP-172.16.98.74 142 0.073491 "Src=55523 Dst=11015 .AP... S=4139707748 L= 72 A=2970345730 W= 8192" TCP 44 IP-172.16.98.74 IP-192.168.43.1 1138 0.000018 "Src=11015 Dst=55523 .AP... S=2970345730 L= 1068 A=4139707820 W=32768" TCP 46 IP-172.16.98.74 IP-192.168.43.1 1138 12.669083 "Src=11015 Dst=55523 .AP... S=2970345730 L= 1068 A=4139707820 W=32768" TCP 47 IP-192.168.43.1 IP-172.16.98.74 142 0.207162 "Src=55523 Dst=11015 .AP... S=4139707820 L= 72 A=2970346798 W= 7336" TCP 48 IP-172.16.98.74 IP-192.168.43.1 70 0.062315 "Src=11015 Dst=55523 .A.... S=2970346798 L= 0 A=4139707892 W=32768" TCP 50 IP-192.168.43.1 IP-172.16.98.74 502 29.332371 "Src=55523 Dst=11015 .AP... S=4139707820 L= 432 A=2970346798 W= 8192" TCP 51 IP-172.16.98.74 IP-192.168.43.1 70 0.069737 "Src=11015 Dst=55523 .A.... S=2970346798 L= 0 A=4139708252 W=32768" TCP 52 IP-172.16.98.74 IP-192.168.43.1 140 17.282767 "Src=11015 Dst=55523 .AP... S=2970346798 L= 70 A=4139708252 W=32768" TCP 54 IP-172.16.98.74 IP-192.168.43.1 140 12.836219 "Src=11015 Dst=55523 .AP... S=2970346798 L= 70 A=4139708252 W=32768" TCP 55 IP-192.168.43.1 IP-172.16.98.74 142 0.070238 "Src=55523 Dst=11015 .AP... S=4139708252 L= 72 A=2970346868 W= 8192" TCP 56 IP-172.16.98.74 IP-192.168.43.1 70 0.069377 "Src=11015 Dst=55523 .A.... S=2970346868 L= 0 A=4139708324 W=32768" TCP
The above trace was filtered to eliminate "unrelated" packets. But when you look at an unfiltered trace it is easy to see what is happening. Note that before every drop there is an ICMP destination unreachable message from 192.168.43.253.
1 IP-192.168.43.1 IP-172.16.98.74 350 "Src=55523 Dst=11015 .AP... S=4139707118 L= 280 A=2970345660 W= 8192" TCP 2 IP-172.16.98.74 IP-192.168.43.1 70 0.061628 "Src=11015 Dst=55523 .A.... S=2970345730 L= 0 A=4139707398 W=32768" TCP 3 IP-192.168.43.1 IP-172.16.98.74 140 4.442807 "Src=55523 Dst=11015 .AP... S=4139707398 L= 70 A=2970345660 W= 8192" TCP 4 IP-172.16.98.74 IP-192.168.43.1 70 0.066472 "Src=11015 Dst=55523 .A.... S=2970345730 L= 0 A=4139707468 W=32768" TCP 5 IP-192.168.43.253 IP-172.16.98.74 74 0.026837 Destination unreachable: 192.168.43.1 ICMP DestUnreach 6 IP-192.168.43.1 IP-172.16.98.74 140 1.414085 "Src=55523 Dst=11015 .AP... S=4139707398 L= 70 A=2970345660 W= 8192" TCP 7 IP-172.16.98.74 IP-192.168.43.1 70 0.000551 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707468 W=32768" TCP 8 IP-172.16.98.74 IP-192.168.43.1 140 11.298757 "Src=11015 Dst=55523 .AP... S=2970345660 L= 70 A=4139707468 W=32768" TCP 9 IP-192.168.43.253 IP-172.16.98.74 74 0.035309 Destination unreachable: 192.168.43.1 ICMP DestUnreach 10 IP-192.168.43.1 IP-172.16.98.74 64 34.029950 "Src=55523 Dst=11015 .A.... S=4139707467 L= 1 A=2970345659 W= 8192" TCP 11 IP-172.16.98.74 IP-192.168.43.1 70 0.000538 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707468 W=32768" TCP 12 IP-192.168.43.1 IP-172.16.98.74 140 13.867582 "Src=55523 Dst=11015 .AP... S=4139707468 L= 70 A=2970345660 W= 8192" TCP 13 IP-172.16.98.74 IP-192.168.43.1 70 0.069607 "Src=11015 Dst=55523 .A.... S=2970345730 L= 0 A=4139707538 W=32768" TCP 14 IP-192.168.43.253 IP-172.16.98.74 74 0.027064 Destination unreachable: 192.168.43.1 ICMP DestUnreach 15 IP-192.168.43.1 IP-172.16.98.74 140 2.844203 "Src=55523 Dst=11015 .AP... S=4139707468 L= 70 A=2970345660 W= 8192" TCP 16 IP-172.16.98.74 IP-192.168.43.1 70 0.000292 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707538 W=32768" TCP 17 IP-172.16.98.74 IP-192.168.43.1 140 9.313404 "Src=11015 Dst=55523 .AP... S=2970345660 L= 70 A=4139707538 W=32768" TCP 18 IP-192.168.43.253 IP-172.16.98.74 74 0.035213 Destination unreachable: 192.168.43.1 ICMP DestUnreach 19 IP-192.168.43.1 IP-172.16.98.74 64 35.834717 "Src=55523 Dst=11015 .A.... S=4139707537 L= 1 A=2970345659 W= 8192" TCP 20 IP-172.16.98.74 IP-192.168.43.1 70 0.000496 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707538 W=32768" TCP 21 IP-192.168.43.1 IP-172.16.98.74 140 12.614147 "Src=55523 Dst=11015 .AP... S=4139707538 L= 70 A=2970345660 W= 8192" TCP 22 IP-172.16.98.74 IP-192.168.43.1 70 0.068548 "Src=11015 Dst=55523 .A.... S=2970345730 L= 0 A=4139707608 W=32768" TCP 23 IP-192.168.43.253 IP-172.16.98.74 74 0.026574 Destination unreachable: 192.168.43.1 ICMP DestUnreach 24 IP-192.168.43.1 IP-172.16.98.74 140 5.445152 "Src=55523 Dst=11015 .AP... S=4139707538 L= 70 A=2970345660 W= 8192" TCP 25 IP-172.16.98.74 IP-192.168.43.1 70 0.000396 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707608 W=32768" TCP 26 IP-172.16.98.74 IP-192.168.43.1 140 6.168950 "Src=11015 Dst=55523 .AP... S=2970345660 L= 70 A=4139707608 W=32768" TCP 27 IP-192.168.43.253 IP-172.16.98.74 74 0.034882 Destination unreachable: 192.168.43.1 ICMP DestUnreach 28 IP-192.168.43.1 IP-172.16.98.74 64 39.631839 "Src=55523 Dst=11015 .A.... S=4139707607 L= 1 A=2970345659 W= 8192" TCP 29 IP-172.16.98.74 IP-192.168.43.1 70 0.000541 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707608 W=32768" TCP 30 IP-192.168.43.1 IP-172.16.98.74 140 9.364319 "Src=55523 Dst=11015 .AP... S=4139707608 L= 70 A=2970345660 W= 8192" TCP 31 IP-172.16.98.74 IP-192.168.43.1 70 0.070426 "Src=11015 Dst=55523 .A.... S=2970345730 L= 0 A=4139707678 W=32768" TCP 32 IP-192.168.43.253 IP-172.16.98.74 74 0.026788 Destination unreachable: 192.168.43.1 ICMP DestUnreach 33 IP-192.168.43.1 IP-172.16.98.74 140 9.905233 "Src=55523 Dst=11015 .AP... S=4139707608 L= 70 A=2970345660 W= 8192" TCP 34 IP-172.16.98.74 IP-192.168.43.1 70 0.000525 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707678 W=32768" TCP 35 IP-172.16.98.74 IP-192.168.43.1 140 1.137104 "Src=11015 Dst=55523 .AP... S=2970345660 L= 70 A=4139707678 W=32768" TCP 36 IP-192.168.43.253 IP-172.16.98.74 74 0.035826 Destination unreachable: 192.168.43.1 ICMP DestUnreach 37 IP-192.168.43.1 IP-172.16.98.74 64 45.450462 "Src=55523 Dst=11015 .A.... S=4139707677 L= 1 A=2970345659 W= 8192" TCP 38 IP-172.16.98.74 IP-192.168.43.1 70 0.000434 "Src=11015 Dst=55523 .A.... S=2970345660 L= 0 A=4139707678 W=32768" TCP 39 IP-192.168.43.1 IP-172.16.98.74 140 4.118404 "Src=55523 Dst=11015 .AP... S=4139707678 L= 70 A=2970345660 W= 8192" TCP 40 IP-172.16.98.74 IP-192.168.43.1 70 0.068311 "Src=11015 Dst=55523 .A.... S=2970345730 L= 0 A=4139707748 W=32768" TCP 41 IP-192.168.43.253 IP-172.16.98.74 74 0.026792 Destination unreachable: 192.168.43.1 ICMP DestUnreach 42 IP-172.16.98.74 IP-192.168.43.1 140 10.473988 "Src=11015 Dst=55523 .AP... S=2970345660 L= 70 A=4139707748 W=32768" TCP 43 IP-192.168.43.1 IP-172.16.98.74 142 0.073491 "Src=55523 Dst=11015 .AP... S=4139707748 L= 72 A=2970345730 W= 8192" TCP 44 IP-172.16.98.74 IP-192.168.43.1 1138 0.000018 "Src=11015 Dst=55523 .AP... S=2970345730 L= 1068 A=4139707820 W=32768" TCP 45 IP-192.168.43.253 IP-172.16.98.74 74 0.161432 Destination unreachable: 192.168.43.1 ICMP DestUnreach 46 IP-172.16.98.74 IP-192.168.43.1 1138 12.669083 "Src=11015 Dst=55523 .AP... S=2970345730 L= 1068 A=4139707820 W=32768" TCP 47 IP-192.168.43.1 IP-172.16.98.74 142 0.207162 "Src=55523 Dst=11015 .AP... S=4139707820 L= 72 A=2970346798 W= 7336" TCP 48 IP-172.16.98.74 IP-192.168.43.1 70 0.062315 "Src=11015 Dst=55523 .A.... S=2970346798 L= 0 A=4139707892 W=32768" TCP 49 IP-192.168.43.253 IP-172.16.98.74 74 0.026991 Destination unreachable: 192.168.43.1 ICMP DestUnreach 50 IP-192.168.43.1 IP-172.16.98.74 502 29.332371 "Src=55523 Dst=11015 .AP... S=4139707820 L= 432 A=2970346798 W= 8192" TCP 51 IP-172.16.98.74 IP-192.168.43.1 70 0.069737 "Src=11015 Dst=55523 .A.... S=2970346798 L= 0 A=4139708252 W=32768" TCP 52 IP-172.16.98.74 IP-192.168.43.1 140 17.282767 "Src=11015 Dst=55523 .AP... S=2970346798 L= 70 A=4139708252 W=32768" TCP 53 IP-192.168.43.253 IP-172.16.98.74 74 0.035411 Destination unreachable: 192.168.43.1 ICMP DestUnreach 54 IP-172.16.98.74 IP-192.168.43.1 140 12.836219 "Src=11015 Dst=55523 .AP... S=2970346798 L= 70 A=4139708252 W=32768" TCP 55 IP-192.168.43.1 IP-172.16.98.74 142 0.070238 "Src=55523 Dst=11015 .AP... S=4139708252 L= 72 A=2970346868 W= 8192" TCP 56 IP-172.16.98.74 IP-192.168.43.1 70 0.069377 "Src=11015 Dst=55523 .A.... S=2970346868 L= 0 A=4139708324 W=32768" TCP 57 IP-192.168.43.253 IP-172.16.98.74 74 0.026787 Destination unreachable: 192.168.43.1 ICMP DestUnreach
So now we know why the packets are being dropped. It still seemed strange that the router or firewall would let every other packet through. I conjectured that there are two routers/firewalls and some kind of load balacing software is alternately sending packets to them. One of them is allowing packets through while the other is not. I never did hear from the customer if this was the case or not but after discussing this with their customer (the people on the remote network) network performance improved significantly, so I assume that this is indeed what was happening.