Accessing files on a USB drive attached to a second router from devices connected to the first requires configuring network routing and file sharing protocols. By ensuring both routers are on the same subnet or properly routed, you can use SMB for Windows/macOS or SFTP/SSHFS for Linux to mount the remote storage as a local drive.
Network Topology and IP Configuration
The most common reason for failure is that the two routers are operating on different subnets with no route between them. To fix this, you must decide whether to use Access Point Mode or Router Mode. If your goal is simple file access across all devices, Access Point mode is often easier because it places all devices on the same LAN segment.
If you keep both routers in Router Mode (NAT), you must ensure the second router's WAN port connects to a LAN port of the first router. This creates a double NAT scenario. While this works, it complicates discovery services like NetBIOS. You need to verify the IP ranges. For example, if the main router is at 192.168.1.1, the second router should ideally be set to 192.168.1.2 with DHCP disabled, or configured with a static IP outside the DHCP pool of the main router but within the same subnet.
For more complex setups involving multiple networks, see Isolating TP-Link Network from Home Network Maintaining Internet Access to understand how traffic flows between isolated segments.
Configuring File Sharing on the Second Router
Before attempting to connect from any client OS, the source device (the second router) must expose the USB drive correctly. Most modern routers support SMB/CIFS (Server Message Block) which is compatible with Windows and macOS, and some support FTP or NFS.
- Enable SMB Sharing: Log into the admin panel of the second router. Navigate to the USB or Storage settings. Look for an option labeled "SMB," "File Sharing," or "Media Server." Enable it.
- Set Permissions: Create a username and password specifically for network access. Avoid using the admin password for the share. Note these credentials down.
- Check Firewall Settings: Some routers have a built-in firewall that blocks incoming SMB traffic (ports 445 and 139). Ensure that "Allow LAN access" or similar is checked for the USB share.
If your router supports advanced features, consider enabling UPnP or SSDP to help devices discover the share automatically. However, manual connection is often more reliable in mixed-router environments.
Connecting from Windows Devices
Windows uses the SMB protocol by default for network shares. Once the second router is configured, follow these steps on your Windows PC connected to the first router.
Open File Explorer and click on This PC. In the address bar, type the UNC path: \\[IP_OF_SECOND_ROUTER]\[SHARE_NAME]. Replace [IP_OF_SECOND_ROUTER] with the actual IP address (e.g., 192.168.1.2) and [SHARE_NAME] with the name of the folder or root directory exposed by the router.
If prompted, enter the username and password you created in the previous section. If the connection fails, ensure that Network Discovery and File and Printer Sharing are turned on in the Windows Control Panel under Network and Sharing Center. You may also need to enable SMB 1.0/CIFS in Windows Features if the router is very old, though this is a security risk and should be avoided if possible.
Connecting from macOS Devices
macOS handles network drives through the Finder. Open a new Finder window and select Go > Connect to Server (or press Cmd + K).
In the server address field, enter: smb://[IP_OF_SECOND_ROUTER]. Click Connect. You will be asked for credentials. Enter the username and password defined on the second router. Once connected, the drive will appear on your desktop and in the sidebar. To make it permanent, drag the mounted volume to the Locations sidebar or add it to Login Items in System Preferences.
Connecting from Linux Devices
Linux users have several options, ranging from GUI tools to command-line mounting. The most robust method is using cifs-utils.
First, install the necessary packages. On Debian/Ubuntu systems, run: sudo apt install cifs-utils. Create a mount point directory: sudo mkdir /mnt/usb_share.
To mount the share manually, use the following command: sudo mount -t cifs //[IP_OF_SECOND_ROUTER]/[SHARE_NAME] /mnt/usb_share -o username=[YOUR_USER],password=[YOUR_PASS]. For persistent access, add an entry to /etc/fstab using the //[IP]/[SHARE] /[MOUNT_POINT] cifs ... syntax.
Alternatively, many Linux distributions support mounting SMB shares directly via Nautilus (GNOME Files) or Dolphin (KDE) by selecting Other Locations and entering the server address. For secure shell-based access if the router supports SSH/SFTP, you can use sshfs to mount the filesystem over an encrypted tunnel, which is safer than plain SMB.
For insights on connecting devices within wireless local networks, refer to Connecting Two Devices on a Wireless Local Network.
Troubleshooting Common Issues
If you cannot reach the IP address, ping it from the client machine. If the ping fails, check the physical Ethernet cable and ensure the second router is receiving power. If the ping succeeds but the share fails, verify the SMB version compatibility. Modern Windows versions disable SMBv1 by default; ensure your router supports SMBv2 or SMBv3.
Firewall rules on the client machine can also block outbound connections to port 445. Check your antivirus or Windows Defender Firewall settings to ensure they are not blocking network discovery.
Frequently Asked Questions
Can I use FTP instead of SMB?
Yes, if your router supports FTP, you can connect using an FTP client like FileZilla or a web browser. However, FTP is less integrated with the OS than SMB, meaning you won't get seamless drag-and-drop access without third-party software mapping the drive.
Why do I get a "Network Path Not Found" error?
This usually indicates that the client cannot resolve the IP address or the specific share name. Verify the exact share name in the router's admin panel and ensure there are no typos in the UNC path. Also, confirm that the client and router are on the same subnet.
Is it safe to leave SMB enabled on my router?
SMB is generally safe if you use strong passwords and keep the router firmware updated. Avoid exposing SMB ports to the public internet. Restrict access to the local LAN only. Using WPA3 encryption for Wi-Fi adds another layer of security against eavesdropping.
How do I find the IP address of my second router?
You can find it by logging into the first router's admin page and checking the list of connected DHCP clients. Alternatively, look at the sticker on the bottom of the second router, or check the ARP table on your computer after pinging the broadcast address.
What if my router doesn't support SMB?
If the router only supports FTP or NFS, you will need to use corresponding clients. For NFS on Linux, use the mount -t nfs command. For FTP, use standard FTP clients. Some older routers may require installing custom firmware like DD-WRT or OpenWrt to enable SMB sharing.