Cannot browse shares through a mobile phone/SMB
Have you ever had the problem of suddenly not being able to browse your Windows computer from your smart phone, using a file explorer like ES File Explorer?
The answer lies within your security settings of the computer rather than your phone. What affects the SMB connection to your computer is the windows firewall, third party firewalls like Anti-Virus software firewalls, external firewalls, nonpaged pool or local security settings of your computer. Also have in mind that the corresponding Windows Services that are responsible for the SMB protocol are “Server Service” and “Workstation Service“.
Windows Services – First thing is to make sure that the Server and Workstation services are running. Click Start -> Run -> type services.msc. Once the window is up, navigate to the above services and make sure they are “Started’. If not right-click them and start them if stopped. If the process of starting hangs it means that you have a problem with the service. Reboot the computer and check if the service has started normally. If it doesn’t start on it’s own or if it starts but at some point it goes unresponsive you will have to troubleshoot it. Search Google and use keywords like “Server/Workstation Service hanging” and etc.
Windows Firewall – First thing you want to try is turning your windows firewall off. If that doesn’t fix your problem and your computer is still unavailable from your smart phone through SMB, that means the problem might be somewhere else. Just informational the SMB TCP port is 445. For SMB via NetBIOS API UDP 137,138 and TCP 137 and 139.
Third Party AV Firewalls – Every Anti Virus software has a “Real-time Protection” on its own. This is a firewall similar to the windows firewall and can many times be the cause of unsuccessful connections to the computer by many applications. Browse your AV and try to make a filter or exception rule for the SMB protocol knowing its ports from above. Ultimately you can try turning it off for a brief moment just to confirm that it is the one blocking the SMB connections.
External Firewalls – External firewalls won’t be the problem if you are connecting to a VPN and then browsing your shares at home or if you are already into the local network via your wireless connection. But if you use any other method to connect to your SMB shares the external firewall like a router might block the SMB connection. Perhaps looking at the router’s settings and port forward the SMB ports can help you.
Non Paged Pool in Windows 7 – If you have noticed not only that you cannot browse successfully through SMB but your Computer browser service starts but if you refresh your Services screen just 1 sec later you will notice that the service stops. Checking the Event Viewer and its System logs will reveal that every time you try an event is logged which is :
Event ID: 2017
The server was unable to allocate from the system nonpaged pool because the server reached the configured limit for nonpaged pool allocations.
Apparently you need to tell Windows that you want to use the machine as a file server and that it should allocate resources accordingly. Set the following registry key to ’1′:
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache
and set the following registry key to ’3′:
After making these changes and restarting it will take effect.
Local Security Settings – This has to be the most significant and the most hidden purpose of why your shares are unavailable. File explorers like ES File Explorer do not support encryption of the passwords sent over the network to authenticate the SMB connection. It rather uses plain text which may cause conflict with the internal security settings of the computer.
Windows XP – Start -> Settings -> Control Panel -> Administrative Tools – > Local Security Settings
Windows 7 – Click Start and type Local Security Policy. Open it.
Reboot the computer.
If for some reason you can’t do it with the above, it can also be done by editing the registry responsible for it –
– Browse to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanWorkStation\parameters]
– Set “EnablePlainTextPassword”=dword:00000001