What causes a packet RST,ASK between client and SMB server?

asked 2020-09-15 05:11:07 +0000

DZ gravatar image

updated 2020-09-15 06:16:00 +0000

Hi, I am currently trying to fix the following error in our network structure. There is following error: There is no SMB connection possible between a client Windows 10 and the servers 2012, 2019. -The local Windows Firewall is disabled

What I see when I try to connect to the Server 2012, 2019 on Windows Explorer, is the following

1. TCP 3-way handshake ([SYN],[SYN,ACK],[ACK])
2. Negotiate Protocol Request from PC to Server
3. Negotiate Protocol Response from Server to PC
4. Session Setup Request, NTLMSSP_NEGOTIATE 
6. Session Setup Request, NTLMSSP_AUTH, User:
7.Session Setup Response
8. [RST,ACK] Seq=734 Ack=6111 Win=0 Len=0

Steps 1-8 will then repeat twice (total 3x) before ultimately failing.

Has anyone ever had this problem?

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Who is sending the RST and how much delay is there between the last "Session Setup Response"?

Also, a pcap file really helps in understanding what is going on. If there is no sensitive data in it, could you share it on a public file-sharing platform like OneDrive, Dropbox, GoogleDrive etc.?

SYN-bit gravatar imageSYN-bit ( 2020-09-15 09:23:52 +0000 )edit