如下是拷貝的抓包描述，每次 10.254.251.74 發給 10.254.251.103 都會發 2 次然后才會有從 103 回包，wireshark 提示[TCP Out-Of-Order]（應該是因為 2 次的 seq 號一樣導致）
還有一個問題就是隔幾個包 10.254.251.103 會給 10.254.251.74 發送一次長度為 0 的包，然后才發送包含資料的報文。
10.254.251.103 是客戶端，和 10.254.251.74 長連接發送業務資料，10.254.251.74 會存盤收到的業務資料，10.254.251.74 收到業務資料后回“ 0004OK..”給 10.254.251.103 （如果回的時候 socket 寫不成功，則會嘗試重寫 3 次，連接不斷只重寫）
850 0.297317 10.254.251.103 10.254.251.74 TCP 52633 > 9978 [PSH, ACK] Seq=1 Ack=1 Win=115 Len=693 TSV=1983788074 TSER=3365181331
857 0.299894 10.254.251.74 10.254.251.103 TCP 9978 > 52633 [PSH, ACK] Seq=1 Ack=694 Win=670 Len=8 TSV=3365181648 TSER=1983788074
858 0.299919 10.254.251.74 10.254.251.103 TCP [TCP Out-Of-Order] 9978 > 52633 [PSH, ACK] Seq=1 Ack=694 Win=670 Len=8 TSV=3365181648 TSER=1983788074
859 0.300071 10.254.251.103 10.254.251.74 TCP 52633 > 9978 [ACK] Seq=694 Ack=9 Win=115 Len=0 TSV=1983788077 TSER=3365181648
868 0.303283 10.254.251.103 10.254.251.74 TCP 52633 > 9978 [PSH, ACK] Seq=694 Ack=9 Win=115 Len=689 TSV=1983788080 TSER=3365181648
871 0.303439 10.254.251.74 10.254.251.103 TCP 9978 > 52633 [PSH, ACK] Seq=9 Ack=1383 Win=670 Len=8 TSV=3365181651 TSER=1983788080
872 0.303441 10.254.251.74 10.254.251.103 TCP [TCP Out-Of-Order] 9978 > 52633 [PSH, ACK] Seq=9 Ack=1383 Win=670 Len=8 TSV=3365181651 TSER=1983788080
873 0.305156 10.254.251.103 10.254.251.74 TCP 52633 > 9978 [PSH, ACK] Seq=1383 Ack=17 Win=115 Len=689 TSV=1983788082 TSER=3365181651
875 0.305851 10.254.251.74 10.254.251.103 TCP 9978 > 52633 [PSH, ACK] Seq=17 Ack=2072 Win=670 Len=8 TSV=3365181654 TSER=1983788082
876 0.305929 10.254.251.74 10.254.251.103 TCP [TCP Out-Of-Order] 9978 > 52633 [PSH, ACK] Seq=17 Ack=2072 Win=670 Len=8 TSV=3365181654 TSER=1983788082
881 0.307979 10.254.251.103 10.254.251.74 TCP 52633 > 9978 [PSH, ACK] Seq=2072 Ack=25 Win=115 Len=748 TSV=1983788084 TSER=3365181654
888 0.309467 10.254.251.74 10.254.251.103 TCP 9978 > 52633 [PSH, ACK] Seq=25 Ack=2820 Win=670 Len=8 TSV=3365181657 TSER=1983788084
889 0.309472 10.254.251.74 10.254.251.103 TCP [TCP Out-Of-Order] 9978 > 52633 [PSH, ACK] Seq=25 Ack=2820 Win=670 Len=8 TSV=3365181657 TSER=1983788084
對端的抓包記錄（截取了一段），TCP Out-Of-Order 在客戶端也是每次發送都會出現，但多一個 TCP Dup ACK，TCP Dup ACK 大概每 15 個包會出現一次，先謝謝幫忙的各位：
1 0.000000 10.254.251.74 10.254.251.103 TCP 9978 > 39934 [PSH, ACK] Seq=1 Ack=1 Win=817 Len=8 TSV=132194778 TSER=3044963545
4 0.019092 10.254.251.103 10.254.251.74 TCP 39934 > 9978 [PSH, ACK] Seq=1 Ack=9 Win=115 Len=672 TSV=3044963566 TSER=132194778
5 0.019111 10.254.251.103 10.254.251.74 TCP [TCP Out-Of-Order] 39934 > 9978 [PSH, ACK] Seq=1 Ack=9 Win=115 Len=672 TSV=3044963566 TSER=132194778
6 0.020369 10.254.251.74 10.254.251.103 TCP 9978 > 39934 [PSH, ACK] Seq=9 Ack=673 Win=817 Len=8 TSV=132194799 TSER=3044963566
7 0.023970 10.254.251.103 10.254.251.74 TCP 39934 > 9978 [PSH, ACK] Seq=673 Ack=17 Win=115 Len=786 TSV=3044963571 TSER=132194799
8 0.023976 10.254.251.103 10.254.251.74 TCP [TCP Out-Of-Order] 39934 > 9978 [PSH, ACK] Seq=673 Ack=17 Win=115 Len=786 TSV=3044963571 TSER=132194799
9 0.024614 10.254.251.74 10.254.251.103 TCP 9978 > 39934 [PSH, ACK] Seq=17 Ack=1459 Win=817 Len=8 TSV=132194803 TSER=3044963571
10 0.027786 10.254.251.103 10.254.251.74 TCP 39934 > 9978 [PSH, ACK] Seq=1459 Ack=25 Win=115 Len=692 TSV=3044963575 TSER=132194803
11 0.027791 10.254.251.103 10.254.251.74 TCP [TCP Out-Of-Order] 39934 > 9978 [PSH, ACK] Seq=1459 Ack=25 Win=115 Len=692 TSV=3044963575 TSER=132194803
12 0.028712 10.254.251.74 10.254.251.103 TCP 9978 > 39934 [PSH, ACK] Seq=25 Ack=2151 Win=817 Len=8 TSV=132194807 TSER=3044963575
13 0.036293 10.254.251.103 10.254.251.74 TCP 39934 > 9978 [PSH, ACK] Seq=2151 Ack=33 Win=115 Len=843 TSV=3044963584 TSER=132194807
14 0.036300 10.254.251.103 10.254.251.74 TCP [TCP Out-Of-Order] 39934 > 9978 [PSH, ACK] Seq=2151 Ack=33 Win=115 Len=843 TSV=3044963584 TSER=132194807
15 0.036581 10.254.251.74 10.254.251.103 TCP 9978 > 39934 [PSH, ACK] Seq=33 Ack=2994 Win=817 Len=8 TSV=132194815 TSER=3044963584
16 0.040643 10.254.251.103 10.254.251.74 TCP 39934 > 9978 [PSH, ACK] Seq=2994 Ack=41 Win=115 Len=691 TSV=3044963588 TSER=132194815
17 0.040651 10.254.251.103 10.254.251.74 TCP [TCP Out-Of-Order] 39934 > 9978 [PSH, ACK] Seq=2994 Ack=41 Win=115 Len=691 TSV=3044963588 TSER=132194815
18 0.041855 10.254.251.74 10.254.251.103 TCP 9978 > 39934 [PSH, ACK] Seq=41 Ack=3685 Win=817 Len=8 TSV=132194820 TSER=3044963588
33 0.081157 10.254.251.103 10.254.251.74 TCP 39934 > 9978 [ACK] Seq=3685 Ack=49 Win=115 Len=0 TSV=3044963629 TSER=132194820
34 0.081162 10.254.251.103 10.254.251.74 TCP [TCP Dup ACK 33#1] 39934 > 9978 [ACK] Seq=3685 Ack=49 Win=115 Len=0 TSV=3044963629 TSER=132194820
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