SMB works on one interface not another

I have a TS451+, Dual 1Gb NICs, running QTS 5.2.7.3297. It is not a domain controller or a member of AD/LDAP and does authentication locally

I’ve been running it on my LAN for a few years with great service. I recently added a new firewall and want to connect the 2nd interface to another port of the firewall (DMZ) for VPN access to keep VPN traffic off my LAN.

If I connect a PC (tried both Win 10 & 11) to the DMZ network and connect to \\QNap-DMZ\ via windows explorer I can see all shared folders. If I click on one of the folders or type in \\QNap-DMZ\Multimedia, I get prompted for a user/PW then it just re-prompts me again. Access Denied. I can access the admin interface and SSH via DMZ.

If I connect a PC (Win11) to the LAN network and connect to \\QNap-LAN\ via windows explorer I can see all shared folders. If I click on one of the folders or type in \\QNap-LAN\Multimedia, I get prompted for a user/PW and then have access to the folder’s contents.

I’ve tried…

Interfaces are both up

Interface getting IP addresses via DHCP then set with static IPs

Disabling Service Binding (That I want to use)

In windows networking I have SMB versions (highest = 3, lowest = 1)

Reset all file and folder permissions on the Multimedia folder.

Checked the SMB Access log. Each attempt shows the host connecting and a “Logged In” action.

I’ve set up Kodi on one of the Win 11 laptops with the \\QNap-DMZ\Multimedia\Video resource and get prompted for a new password when I try to connect from the DMZ network.

/mnt/HDA_ROOT/.config/smb.conf and /etc/smb.conf match (they might be symbolic link?)

I’d love to get some help here. I’ve been fighting with this for a few days.

Make sure the NAS is not ACTUALLY connected to a DMZ (very bad idea), if it’s a additional VPN network subnet, sure.

What are the subnets involved in either network ?

I just call the interface DMZ4. It’s an interface on the firewall that has no external exposure. It is reached via a VPN tunnel into my OPNSense firewall.

LAN is 10.10.20.0/24 (QNap is 10.10.20.205) and DMZ4 is 10.10.40.0/24 (QNap is 10.10.40.205)

VPN Subnet is 10.10.70.0/24. But SMB doesn;t even work when I have a laptop on the 10.10.40.x network

One hunch was that it could be a saved credential issue on your clients, but if there is different subnets it’s should not matter. Can you try a non Windows client to test?

I don’t have any non-windows machines. But I have a work laptop (Win 10) that’s never been connected to either Qnap interface before today. I get the same behavior. I’ve also used the Windows Credential manager to delete saved credentials.

If it had saved credentials and it prompted me for new ones and I entered those, would the new credentials not be used at that point for that \\IP\share?

All of this works flawlessly on the 10.10.20.0/24 subnet

If the SMB service was blocked on that 10.10.40.0/24 subnet, you would not get a directory listing though (just a timeout)

The PC I’m connecting with is on the .40 subnet. Nothing to block it. I can ping, telnet, and log into the web interface of the Qnap machine from that network. It isn’t a timeout. It comes back pretty quick with an Access Denied message and a re-prompt for credentials.

Interesting…

PC on LAN (10.10.20.0/24), Windows explorer to \\10.10.20.205\Multimedia. Connects

PC on LAN, Explorer to \\10.10.40.205\Multimedia. Connects

PC on DMZ4, Explorer to \\10.10.40.205\Multimedia. Prompt for credentials, instant reply for new PW and Access Denied message.

It’s like it doesn’t like anything from the .40 network.

So you have a route from 10.10.20.0 to 10.10.40.0 ?
QuFirewall is not active ?

QuFirewall is not installed.

My firewall is currently allowing all/any/anywhere for LAN and the same for DMZ. For testing purposes. Once this is straightened out I’ll clamp down the firewall rules for DMZ from the other interfaces

I completely disconnected the interface for 10.10.20. Switched the default gateway to interface 2.

Connected to the Web UI on 40.205. No problems.

Still having the same SMB issues on \\10.10.40.205\Multimedia

I think I’ll swap IP addresses on the 2 interfaces and swap cables and see what happens. But that’s a job for tomorrow.

OK. I swapped MAC assignments on my firewall and swapped cables in the ethernet ports.

Now Interface 1 is on the 40 network and Interface 2 is on the 20 network.

Same problem. SMB works perfectly on 20.205. But keeps asking for user/PW on the 40.205 interface. This is from a PC connected to the 40 network. If I just connect the PC to the 20 network, it can connect to 40.205\multimedia just fine.

I’m going to start a ticket with the SMB 4.15.004 and point to this thread.

I was contacted regarding my ticket and shown how to download logs.

looking at the smb.conf file I see

hosts allow = 10.10.20.*

To add networks for shared folders… Under Shared folder permissions. It defaults to user group permissions, but there’s also microsoft networking host access.

I added the 10.10.40.* network.

It works like a charm now.