Connection goes FIN,ACK after PSH, ACK

asked 2021-11-29 20:07:10 +0000

UnnamedF gravatar image

updated 2021-11-30 13:48:13 +0000

Hi, i need help to identify what could be the problem that causes this issue, i've tried a lot stuff but nothing helped, the rare thing is that one computer that i don't have has connected to the device witch is a KT400 but the server from were i tried can't, so i think it could be the SO or some configuration in it.

Windows server 2016.

4842    10.762676   10.100.57.27    10.100.57.100   TCP 60  51960 → 18802 [RST] Seq=2 Win=0 Len=0

4843    10.763309   10.100.57.27    10.100.57.100   TCP 62  51961 → 18802 [SYN] Seq=0 Win=32768 Len=0 MSS=1460 SACK_PERM=1

4844    10.763396   10.100.57.100   10.100.57.27    TCP 62  18802 → 51961 [SYN, ACK] Seq=0 Ack=1 Win=8192 Len=0 MSS=1460 SACK_PERM=1

4845    10.763840   10.100.57.27    10.100.57.100   TCP 60  51961 → 18802 [ACK] Seq=1 Ack=1 Win=33580 Len=0

4846    10.764501   10.100.57.27    10.100.57.100   TCP 95  51961 → 18802 [PSH, ACK] Seq=1 Ack=1 Win=33580 Len=41

4935    10.819760   10.100.57.100   10.100.57.27    TCP 54  18802 → 51961 [ACK] Seq=1 Ack=42 Win=64240 Len=0

12100   26.804255   10.100.57.100   10.100.57.27    TCP 54  18802 → 51961 [FIN, ACK] Seq=1 Ack=42 Win=64240 Len=0

12101   26.804834   10.100.57.27    10.100.57.100   TCP 60  51961 → 18802 [ACK] Seq=42 Ack=2 Win=33580 Len=0

12542   27.784711   10.100.57.27    10.100.57.100   TCP 60  51961 → 18802 [FIN, ACK] Seq=42 Ack=2 Win=33580 Len=0

12543   27.784783   10.100.57.100   10.100.57.27    TCP 54  18802 → 51961 [ACK] Seq=2 Ack=43 Win=64240 Len=0

12544   27.785242   10.100.57.27    10.100.57.100   TCP 60  51961 → 18802 [RST] Seq=43 Win=0 Len=0
edit retag flag offensive close merge delete

Comments

After frame 4935, there isn't any more data until 16s later when 10.100.57.100 sends a FIN. I wonder if 10.100. 57.27, received the ACK in frame 4935. Is it possible to do simultaneous capture in the path that is close to 10.100.57.27?

BigFatCat gravatar imageBigFatCat ( 2021-11-29 23:27:20 +0000 )edit

its a door controller so theres no way to do that :(

UnnamedF gravatar imageUnnamedF ( 2021-11-30 14:27:33 +0000 )edit

There is an install guide on the kantech training page.
Do you know which diagram in the manual looks like your config?
Maybe the issue is between the server and the controller (port 18810 according to the manual).

Chuckc gravatar imageChuckc ( 2021-11-30 20:10:19 +0000 )edit