Setting up SMB/CIFS shares and mounting them on macOS/Windows

SMB (also called CIFS) is the network protocol behind “Map network drive” on Windows or “Connect to Server” in the Mac Finder. On a Synology, a few clicks give you shared folders that feel like local drives from the outside.

Important note up front: SMB straight over the open internet is a well-known security risk, and many internet providers block port 445 anyway. We recommend SMB only inside a VPN or on the same network as the Synology. If you want to access it over the internet without a VPN, use Synology Drive or WebDAV instead.

Enabling SMB on the Synology

In most setups, SMB is already active. If not:

1. Control Panel → File Services → SMB/AFP/NFS.
2. SMB tab → check Enable SMB service.
3. Minimum version: SMB 2 (SMB 1 is obsolete, don’t turn it on).
4. Maximum version: SMB 3.
5. Save.

Creating a shared folder

If you don’t have one yet:

1. Control Panel → Shared Folder → Create.
2. Pick a name — say Documents or Family.
3. Select a volume — if there’s more than one.
4. Check Enable Recycle Bin (deleted files land in the recycle bin first).
5. Permissions: which users may read/write.
6. Optional: encryption for sensitive data.

Mounting on macOS

In the Finder:

1. Keyboard shortcut Cmd+K or menu Go → Connect to Server.
2. Enter the URL: smb://<deine-synology-ip-oder-domain>/<freigabename>
   • Example: smb://12345.nas.xaweho.de/Documents
3. Click Connect.
4. Log in with your DSM user and password.
5. Optional: “Remember this password in my keychain” for automatic login.

The folder shows up in the Finder under “Locations”. You can read and write there like on a local drive.

Mounting on Windows

In Windows 10/11:

1. Open File Explorer.
2. This PC → right-click → Map network drive.
3. Pick a drive letter (e.g. Z:).
4. Folder: \\<deine-synology-ip-oder-domain>\<freigabename>
   • Example: \\12345.nas.xaweho.de\Documents
5. Check Connect using different credentials.
6. Finish.
7. Log in with your DSM user and password.

Mounting on Linux

Via CLI:

# One-time: install cifs-utils
sudo apt install cifs-utils

# Mount
sudo mount -t cifs //12345.nas.xaweho.de/Documents /mnt/synology \
  -o username=DEIN-USER,password=DEIN-PASSWORT,vers=3.0,uid=$(id -u),gid=$(id -g)

For a persistent mount: add an entry to /etc/fstab.

SMB over the internet — what you need to know

If your Synology sits with us and you want to use SMB from home, the traffic goes over the internet. Three problems:

1. Provider blocking: many DSL providers (Telekom, Vodafone, etc.) block outgoing port 445. You can try port-forwarding tricks on your home router, but most of the time SMB over DSL simply doesn’t work.

2. SMB security wasn’t built for open networks. Even SMB 3 with encryption is not the standard you want on the open internet. Brute-force bots actively scan for SMB endpoints.

3. No meaningful auth hardening at the SMB level. No 2FA, no auto-block for SMB logins (only for DSM logins).

Solutions:

• Enable a VPN on the Synology and route SMB through the VPN tunnel. Install the VPN Server package, set up the client on your Mac/Windows machine, and the Synology appears local — SMB works without internet exposure.
• WebDAV instead of SMB — works directly in Finder/Explorer without a VPN, is HTTPS-based and safe over the internet. See Enabling and using WebDAV.
• Synology Drive client — if file sync is your main goal, Drive is the better route.

In practice, our customers use SMB mainly when they have a Synology at home and run it on the home network, or when the Synology sits with us and they connect via VPN.

Best practices

One shared folder per use case. Don’t dump everything into /data. Better: Documents, Family, Movies, Backup — separated, with separate permissions.

Create users with minimal rights. Family members and colleagues often don’t need admin. One user per person, with only the required shares enabled.

Enable the recycle bin on every shared folder. Accidental deletions land there and stay until you empty the bin — there is no automatic emptying by default. If you want one: set it up in Task Scheduler, e.g. delete files older than 30 days. Without the recycle bin, files are gone instantly.

Check the SMB logs. In the Log Center, filter for “SMB” — you’ll see connect/disconnect events and can spot suspicious activity.

Frequently asked questions

What’s the difference between SMB and CIFS? Historical baggage. CIFS was the older name (developed by IBM/Microsoft), SMB the new one (modernized). In practice: today you mean the same thing. SMB 1 = old CIFS, SMB 2 and 3 = modern versions.

Do I have to enable SMB 1 for old devices? We strongly recommend no. SMB 1 has known security holes (the WannaCry exploit). If you really have an old device (Windows XP, an aging printer) that only speaks SMB 1, replace the device rather than opening up SMB 1.

How do I see who’s currently connected via SMB? Resource Monitor → Connected Users in DSM. Per user, you can see which files they currently have open.

Does Time Machine work over SMB? Yes. In Control Panel → File Services → Advanced you can mark a shared folder as a Time Machine target. In our experience, very stable with DSM 7 — DSM 6 occasionally had sync problems.

Can I set permissions per file? On Btrfs: yes, with ACLs. Control Panel → Shared Folder → edit the folder → Advanced Share Permissions. Detailed read/write/delete rights per user.

What if the connection is “gone”? In the Mac Finder, the share disappears after inactivity. The next click reconnects it. If the connection is genuinely broken: log out and reconnect.

How many parallel SMB connections can the NAS handle? Synology Plus models (DS225+, DS925+, DS1625+) go up to 200–500 parallel sessions. For private customers with a handful of devices, a non-issue.

What’s next

• Enabling and using WebDAV
• Setting up Synology Drive for file sharing and sync
• Securing the admin account on your Synology