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SFTP connection issue RST sent intead of ACK

Dear All,

I am trying to set up an SFTP connection in one of my software, but it keeps throwing error unable to connect. If I try to set up a different SFTP site, it works without an error. If running wireshark I get the following:

2600 30.950722 10.50.2.11 52.220.123.79 TCP 66 64410 → 22 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 MSS=1460 WS=256 SACK_PERM=1

2647 31.213991 52.220.123.79 10.50.2.11 TCP 66 22 → 64410 [SYN, ACK] Seq=0 Ack=1 Win=26883 Len=0 MSS=1460 SACK_PERM=1 WS=128

2648 31.214009 10.50.2.11 52.220.123.79 TCP 54 64410 → 22 [RST] Seq=1 Win=0 Len=0

The other site gives me the following: 35938 211.569592 10.50.2.11 195.144.107.198 TCP 66 64431 → 22 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 MSS=1460 WS=256 SACK_PERM=1

35983 211.588596 195.144.107.198 10.50.2.11 TCP 66 22 → 64431 [SYN, ACK] Seq=0 Ack=1 Win=8192 Len=0 MSS=1460 WS=256 SACK_PERM=1

35984 211.588626 10.50.2.11 195.144.107.198 TCP 54 64431 → 22 [ACK] Seq=1 Ack=1 Win=65536 Len=0

I can see that the client is dropping the connection, but I am unable to find why. The only difference I can se is that WS and WIN has different values. The full packet log can be found here: https://pastebin.com/YWNqvC5H

From this I cannot find the problem. Can anyone see what could be the problem?

Thank you,

SFTP connection issue RST sent intead of ACK

Dear All,

I am trying to set up an SFTP connection in one of my software, but it keeps throwing error unable to connect. If I try to set up a different SFTP site, it works without an error. If running wireshark I get the following:

2600 30.950722      10.50.2.11            52.220.123.79         TCP      66     64410 → 22 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 MSS=1460 WS=256 SACK_PERM=1

SACK_PERM=1 2647 31.213991 52.220.123.79 10.50.2.11 TCP 66 22 → 64410 [SYN, ACK] Seq=0 Ack=1 Win=26883 Len=0 MSS=1460 SACK_PERM=1 WS=128

WS=128 2648 31.214009 10.50.2.11 52.220.123.79 TCP 54 64410 → 22 [RST] Seq=1 Win=0 Len=0

Len=0

The other site gives me the following:

35938 211.569592     10.50.2.11            195.144.107.198       TCP      66     64431 → 22 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 MSS=1460 WS=256 SACK_PERM=1

SACK_PERM=1 35983 211.588596 195.144.107.198 10.50.2.11 TCP 66 22 → 64431 [SYN, ACK] Seq=0 Ack=1 Win=8192 Len=0 MSS=1460 WS=256 SACK_PERM=1

SACK_PERM=1 35984 211.588626 10.50.2.11 195.144.107.198 TCP 54 64431 → 22 [ACK] Seq=1 Ack=1 Win=65536 Len=0

Len=0

I can see that the client is dropping the connection, but I am unable to find why. The only difference I can se is that WS and WIN has different values. The full packet log can be found here: https://pastebin.com/YWNqvC5H

From this I cannot find the problem. Can anyone see what could be the problem?

Thank you,