TCP 接続が予期しない RST(リセット) で終了することがある

Issue

• Red Hat システムは、不明な理由で RST パケットを送信しています。

$ tshark -t dd -r capture.pcap "tcp.stream == 0"
51780 21:13:37.129318   0.000000 192.168.100.10 10.20.30.40 TCP 74 64085 > 22501 [SYN] Seq=2466982502 Win=14600 Len=0 MSS=1460 SACK_PERM=1 TSval=3311535022 TSecr=0 WS=128 
51793 21:13:37.131359   0.002041 10.20.30.40 192.168.100.10 TCP 60 22501 > 64085 [SYN, ACK] Seq=2556619282 Ack=2466982503 Win=65535 Len=0 MSS=1380 
51794 21:13:37.131382   0.000023 192.168.100.10 10.20.30.40 TCP 54 64085 > 22501 [ACK] Seq=2466982503 Ack=2556619283 Win=14600 Len=0 
51799 21:13:37.131875   0.000493 192.168.100.10 10.20.30.40 HTTP 223 GET /XmasServlet/XmasServlet?info=PIN&msisdn=306981323262 HTTP/1.1  
51803 21:13:37.133872   0.001997 10.20.30.40 192.168.100.10 HTTP 166 HTTP/1.1 200 OK  
51804 21:13:37.133881   0.000009 192.168.100.10 10.20.30.40 TCP 54 64085 > 22501 [ACK] Seq=2466982672 Ack=2556619395 Win=14600 Len=0 
51805 21:13:37.134021   0.000140 10.20.30.40 192.168.100.10 HTTP 173 Continuation or non-HTTP traffic 
51806 21:13:37.134028   0.000007 192.168.100.10 10.20.30.40 TCP 54 64085 > 22501 [ACK] Seq=2466982672 Ack=2556619514 Win=14600 Len=0 
51810 21:13:37.134381   0.000353 192.168.100.10 10.20.30.40 TCP 54 64085 > 22501 [RST, ACK] Seq=2466982672 Ack=2556619514 Win=14600 Len=0 

• ほとんどの場合、接続は FIN パケットの通常の通過で終了します。

$ tshark -t dd -r capture.pcap "tcp.stream == 1"
48545 21:13:35.827904   0.000000 192.168.100.10 10.20.30.40 TCP 74 64072 > 22501 [SYN] Seq=1723152983 Win=14600 Len=0 MSS=1460 SACK_PERM=1 TSval=3311533721 TSecr=0 WS=128 
48568 21:13:35.829935   0.002031 10.20.30.40 192.168.100.10 TCP 60 22501 > 64072 [SYN, ACK] Seq=1170803760 Ack=1723152984 Win=65535 Len=0 MSS=1380 
48569 21:13:35.829945   0.000010 192.168.100.10 10.20.30.40 TCP 54 64072 > 22501 [ACK] Seq=1723152984 Ack=1170803761 Win=14600 Len=0 
48576 21:13:35.830509   0.000564 192.168.100.10 10.20.30.40 HTTP 223 GET /XmasServlet/XmasServlet?info=PIN&msisdn=306981323262 HTTP/1.1  
48599 21:13:35.832546   0.002037 10.20.30.40 192.168.100.10 HTTP 166 HTTP/1.1 200 OK  
48600 21:13:35.832559   0.000013 192.168.100.10 10.20.30.40 TCP 54 64072 > 22501 [ACK] Seq=1723153153 Ack=1170803873 Win=14600 Len=0 
48601 21:13:35.832568   0.000009 10.20.30.40 192.168.100.10 HTTP 173 Continuation or non-HTTP traffic 
48602 21:13:35.832573   0.000005 192.168.100.10 10.20.30.40 TCP 54 64072 > 22501 [ACK] Seq=1723153153 Ack=1170803992 Win=14600 Len=0 
48611 21:13:35.834868   0.002295 192.168.100.10 10.20.30.40 TCP 54 64072 > 22501 [FIN, ACK] Seq=1723153153 Ack=1170803992 Win=14600 Len=0 
48612 21:13:35.836636   0.001768 10.20.30.40 192.168.100.10 TCP 60 22501 > 64072 [ACK] Seq=1170803992 Ack=1723153154 Win=65535 Len=0 
48613 21:13:35.836665   0.000029 10.20.30.40 192.168.100.10 TCP 60 22501 > 64072 [FIN, ACK] Seq=1170803992 Ack=1723153154 Win=65535 Len=0 
48614 21:13:35.836676   0.000011 192.168.100.10 10.20.30.40 TCP 54 64072 > 22501 [ACK] Seq=1723153154 Ack=1170803993 Win=14600 Len=0