Question Trouble accessing Synology DS218J NAS from Windows 10 (SMB traffic ends at Negotiate Protocol Response, doesn't proceed to Session Setup Request)

[Goi]

Hi,

I have a Synology DS218J on SMB. I have been able to access it via Windows Explorer with \\hostname just fine, but I just tried today and it no longer works. I get the following error message when I try to access a folder within the NAS

I get the following error message when I try to access the NAS hostname/IP address directly

When I try to map a new network drive, it doesn't detect anything on my network.

The Synology web portal works fine. I'm able to access it on my web browser. I'm also able to ping it just fine. I'm also able to access it on my Android device using the DS file app. However, I can't access it via Windows Explorer either via \\hostname or \\ipaddress.

I tried net use * /delete and then manually add the NAS root or the shared folders. Here are the results:
"net use X: \\hostname or IP address" - The network path was not found.

"net use X: \\hostname or IP address\SharedFolder" - System error 1790 has occurred. The network logon failed.

If I try the above net use command again, I'll get "System error 59 has occurred. An unexpected network error occurred."

I also tried the following:
"pushd \\hostname or IP address\SharedFolder" - I get either "The operation being requested was not performed because the user has not been authenticated." or "A device attached to the system is not functioning."

I've tried rebooting both my PC and the NAS, disabling(then re-enabling) SMBv1, disabling IPv6, turning on network discovery and file and printer sharing (though this should only affect my sharing of my PC right?)

What's wrong?

 

[mxnerd]

As I said earlier, before anything else, you should at least set any Windows PC or laptop' s network profile to Private.

You only use Public profile at cafe/fast food chain. or any public network/wifi.

 

[mxnerd]

Follow the steps here.

My Synology NAS doesn't show up in Windows File Explorer. What can I do? - Synology Knowledge Center

Synology Knowledge Center offers comprehensive support, providing answers to frequently asked questions, troubleshooting steps, software tutorials, and all the technical documentation you may need.

www.synology.com

Make sure your NAS has local master browser enabled.

Then power down everything. Wait a few minutes. And then power up your NAS first, then your PC and your laptop.

 

[Goi]

Problem solved! It was a problem with my desktop's outgoing NTLM authentication being denied in secpol.msc. ApparenEnabled it, and it works.

 

[mxnerd]

This one?

Network Security: Restrict NTLM: Outgoing NTLM traffic to remote servers

docs.microsoft.com

according to MS's doc, "Not Defined" should be the same as "Allow all"

==

My PC settings.

 

[Goi]

Yup, for some reason it was set to Deny All, and my NAS is configured to accept only NTLM authentication, hence my desktop reset the connection after the Negotiate Protocol Response packet. Funny thing is I don't even remember setting this...also, performing a network reset also apparently didn't reset this to its default setting.