The QNAP TS-251D
Intel Dual-Core Multimedia NAS with a PCIe Slot for Extending NAS Functionality
The TS-251D integrates secure data storage and multimedia entertainment into one device. Featuring a PCIe slot, the TS-251D allows you to flexibly extend NAS functionality and potential applications. You can enhance overall system performance by installing a QNAP QM2 card for M.2 SSD caching/10GbE connectivity combined with Qtier auto-tiering storage and installing a 10GbE/5GbE/2.5GbE network expansion card. In addition, TS-251D can be used with QNAP's smart AI photo management application, QuMagie, which integrates AI image recognition to group similar photos together in album "People", "Things" and "Places". The TS-251D features an HDMI slot to stream multimedia throughout your home. The TS-251D supports dual-channel hardware decoding and transcoding, allowing you to view NAS media files smoothly across various devices.
Intel® Celeron® J4005 Dual-Core Processor and AES-NI Hardware Encryption
Powered by Intel® Celeron® J4005 dual-core 2.0 GHz processor (burst up to 2.7 GHz), DDR4 RAM (up to 8 GB), one Gigabit LAN port, and supports SATA 6Gb/s hard drives, the TS-251D combines network expansion cards to create dependable read/write performance. The TS-251D features Intel® AES-NI 256 hardware-accelerated encryption for both full NAS volumes and shared folders, boosting system performance while securing sensitive data stored in the TS-251D.
Smart AI Photo Management
QuMagie integrates QuMagie Core AI image recognition technology for facial recognition, subject identification, and geotagging photos. Similar photos are categorized into People, Places, and Things albums. Moreover, QuMagie features a built-in timeline scroll, customizable folder covers, iOS® Live Photo display and a powerful search tool, to provide you with the ultimate photo management and image sharing solution.
Learn More: QuMagie
Real-Time 4K Video Transcoding
Featuring advanced Intel® UHD Graphics, the TS-251D supports dual-channel 4K hardware decoding and real-time transcoding, allowing you to convert videos to universal file formats that can be smoothly played across various devices*. You can also watch high-quality 4K media files on an HDTV using the HDMI output or with Plex® Media Server to stream media files to mobile devices and media streaming devices (including DLNA®, Roku®, Apple TV® (via Qmedia), Amazon Fire TV® and Chromecast™). The QNAP RM-IR004 remote control (sold separately) can be configured using QButton to customize individual button actions, providing a more user-friendly NAS experience.
Learn More: Plex Media Server
Multiple Ways To Enjoy Your Multimedia
QNAP provides a wide range of multimedia applications for you to easily enjoy photos, music, and videos.
- Multimedia Console consolidates all QTS multimedia applications into one app for easier and centralized multimedia app management.
- Cinema28 enables single-interface management of all media files and can stream files to every connected device throughout your home.
- Qmedia allows music, photos and videos to be effortlessly streamed to Android TV™, Apple TV® (via Qmedia), and Amazon Fire TV or set-top boxes.
Easy and Secure File Management
File Station centralizes files stored on your TS-251D and in the cloud. You can easily upload files from your computer, drag and drop files between folders, rename files, delete files, and configure file and folder permissions to prevent unauthorized access. Moreover, with Microsoft Office Online you can open and modify Microsoft Office documents stored on the TS-251D, without having to download Word documents, Excel worksheets, and PowerPoint presentations from your NAS to the PC. When it comes to sharing sensitive or confidential files on the TS-251D, you can use File Station to enhance data security effectively by encrypting files into a .qenc file, set a password, and then have file recipients use QENC Decrypter to decrypt the sent file.
Multi-Point File Backup, Access, and Sync
The TS-251D stores data and files centrally, and supports file sharing protocols, including SMB/CIFS, AFP and NFS for Windows®, Mac®, and Linux®/UNIX® devices. Coupled with Qsync (a utility that transforms a QNAP NAS into a secure, high-capacity data center for file synchronization) any file uploaded to the TS-251D becomes available for all linked devices, such as computers, laptops, and mobile devices. Hybrid Backup Sync helps you easily backup or synchronize data on the TS-251D to another QNAP NAS, remote servers, or cloud storage for disaster recovery. Additionally, QuDedup technology greatly improves the efficiency of multi-version backup to the destination storage, while optimizing storage utilization. You can install the QuDedup Extract Tool on your computer and restore deduplicated files to their normal status.
Protect Important Data With Snapshots
Snapshots help protect your data by fully recording the NAS system state and metadata. You can use snapshots to quickly restore files to a previously-recorded state when files are accidentally deleted or modified, or when the system is compromised by ransomware. QNAP snapshots are block-based and only record modified data. Not only does this save storage space, but also reduces the time required to back up and restore data.
Learn More: Volume & LUN Snapshots
Extend NAS Functionality With The PCIe Slot
With a PCIe expansion Gen 2.0 x 4 slot, the TS-251D provides flexibility in extending NAS functionality and potential applications. To optimize system performance, install a QNAP QM2 card for M.2 SSD caching/10GbE connectivity and use with Qtier tiered storage for optimal system performance. You can also use the TS-251D as a wireless access point by installing a compatible QNAP QWA-AC2600 wireless network card to create a wireless media streaming environment. Moreover, by configuring the QXG-10GbE/5GbE network expansion cards, you can upgrade your network to high-speed connectivity with an existing CAT 5e cable. Alternatively, you can add an affordable QNAP QNA-UC5G1T USB 3.2 Gen 1 to 5GbE adapter to your TS-251D and laptop to enjoy higher network speeds, or boost the USB connectivity of the TS-251D by installing a USB 3.2 Gen 2 (10Gbps) card.
QVR Pro Safeguards Your Environment
QNAP's QVR Pro surveillance solution allows you to arrange dedicated, independent storage space for surveillance data on the TS-251D and leverages scalable storage advantages. With QVR Pro, camera management, storage space allocation, camera live view, and playback is greatly simplified. You can also use USB webcams as network cameras with the QUSBCam2 app, and remotely monitor surveillance feeds anytime with QVR Pro Client mobile app.
Notes: 1. QVR Pro is available for the QNAP NAS models with a least 4GB RAM, QNAP NAS with 2GB RAM please use Surveillance Station. 2. The maximum number of channels supported varies by NAS model, network configuration, and camera settings. For more information, visit https://www.qnap.com/go/qvr-nas-selector.
Multiply Your Productivity
The app-driven QTS operating system provides solutions for simplifying file backup, management, search, and more.
- Centrally manage and switch between different email accounts, back up emails to the NAS, and safeguard email security and personal privacy. Learn More: QmailAgent
- Notes Station 3 can bring the advantages of collaborative note-taking with improved productivity to provide higher efficiency for your workgroup. Learn More: Notes Station 3
- Qfiling automates file organization. Files are automatically archived into folders based on your settings. Learn More: Qfiling
- Qsirch quickly finds images, music, videos, documents, emails, and other files. Learn More: Qsirch
Flexible and Economical Storage Expansion
QNAP provides an easy and flexible solution for increasing storage capacity before you run out of storage space. Here are the following ways you can expand NAS storage for accommodating data and business growth
- Hot-swap lower-capacity drives with larger-capacity drives for your QNAP NAS to grow with your business. Learn More: Online RAID Capacity Upgrade
- Use Virtual JBOD (VJBOD) to expand storage capacity by using unused storage in other QNAP NAS. Up to 8 QNAP NAS can be mounted as local disks on the TS-251D.Learn More: VJBOD
- Easily expand NAS capacity by connecting two TR-002, TR-004 USB hardware RAID external enclosures with QNAP's Storage & Snapshots Manager application. Learn More: TR-002 , TR-004
Extend hardware warranty up to 5 years
The TS-251D is backed by a 2-year warranty at no additional costs. You can purchase a warranty extension that extends your warranty coverage up to 5 years.
Learn More: QNAP warranty services
- The PCIe port supports the installation of a 10GbE/5GbE/2.5GbE/ network expansion card, a QM2 card, a USB 3.2 Gen 2 (10Gbps) card, or a wireless network card.
- Provide 4K media playback and online transcoding, while enabling cross-device multimedia viewing via HDMI output or streaming applications.
- Snapshots fully record the system status and data. If files are accidentally deleted or modified, you can quickly restore previously-recorded data.
- QNAP provides a wide range of multimedia applications. You can manage all apps through the Multimedia Console to simplify management.
- HBS backs up and synchronizes NAS data to other remote servers or cloud storage, while QuDedup deduplicates data at the source to reduce network bandwidth and storage space.
- Use VJBOD (Virtual JBOD) to expand your storage capacity by using the unused storage of other QNAP NAS. Connect up to two TR series USB storage enclosure.
|Make and Model||Qnap TS-251D 2-Bay NAS|
|CPU||Intel® Celeron® J4005 dual-core 2.0 GHz processor ( Burst up to 2.7 GHz )|
|CPU Architecture||64-bit x86|
|Graphic Processors||Intel® HD Graphics 600|
|Floating Point Unit||Yes|
|System Memory||2 GB SO-DIMM DDR4 (1 x 2 GB)|
|Maximum Memory||8 GB (2 x 4GB)|
|Memory Slot||2 x SO-DIMM DDR4 (For dual-DIMM configuration, you must use a pair of identical DDR4 modules.)|
|Flash Memory||4GB (Dual boot OS protection)|
|Drive Bay||2 x 3.5-inch SATA 6Gb/s, 3Gb/s ( The system is shipped without HDD. For the HDD compatibility list, please visit https://www.qnap.com/compatibility /)|
|Drive Compatibility||3.5-inch SATA hard disk drives
2.5-inch SATA hard disk drives
2.5-inch SATA solid state drives
|M.2 SSD Slot||Optional via a QM2 PCIe adapter|
|SSD Cache Acceleration Support||Yes|
|Gigabit Ethernet Port (RJ45)||1 ( Expandable with an optional PCIe adapter)|
|5 Gigabit Ethernet Port||( Expandable with an optional PCIe adapter)|
|10 Gigabit Ethernet Port||( Expandable with an optional PCIe adapter)|
|PCIe Slot||1 (Slot 1: PCIe Gen 2 x4) Note:PCIe bandwidth limitations will restrict the NAS 10GbE performance.|
|USB 2.0 port||3|
|USB 3.2 Gen 1 port||2|
|USB 3.2 Gen 2 (10Gbps) Port||Optional via a PCIe expansion card|
|IR Sensor||Yes (Optional QNAP RM-IR004 remote control)|
|HDMI Output||1, HDMI 2.0|
|Operating System||QTS 4.4.1 (embedded Linux)|
|Supported Client Operating Systems||
Apple Mac OS 10.7 or later
Linux and UNIX
Microsoft Windows 7, 8, and 10
Microsoft Windows Server 2003, 2008 R2, 2012, 2012 R2 and 2016, 2019
Apple Safari 7 or later
Microsoft Internet Explorer 10 or later
|Supported Languages||Chinese (traditional and simplified), Czech, Danish, Dutch, English, Finnish, French, German, Greek, Hungarian, Italian, Japanese, Korean, Norwegian, Polish, Portuguese (Brazil), Romanian, Russian, Spanish, Swedish, Thai, and Turkish|
|Supported File Systems||
Internal hard drive (EXT4) External hard drive (EXT3, EXT4, NTFS, FAT32, HFS+, and exFAT)
Note: To use exFat you must purchase an exFAT driver license from License Center.
|Network & Virtual Switch||
TCP/IP: Dual stack (IPv4 and IPv6)
Port trunking（Link aggregation）
DHCP server and client
USB Wi-Fi adapter
Note: This feature does not support ad hoc networks because of security considerations.
NCSI (Network Connectivity Status Indicator)
DDNS settings (Customize & Multiple Service)
|Web Server||HTTP/HTTPS Connections (TLS 1.0/1.1/1.2)
Supports WebDAV Connection
Supports Virtual Host (Max: 32)
Importable SSL Certificate
|Security||Network access protection with auto-blocking (SSH, Telnet, HTTP(S), FTP, CIFS/SMB, and AFP)
Host access control for shared folders (CIFS/SMB)
AES 256-bit folder-based and volume-based encryptions which are validated by FIPS 140-2 CAVP (Cryptographic Algorithm Validation Program) 256-bit external drive encryption (AES)
|Storage Management||Supported RAID types: RAID 0, 1, JBOD, Single
RAID Hot Spare and Global Hot Spare
RAID Rebuild Speed Customization
Online RAID capacity expansion
|iSCSI (IP SAN)||iSCSI targets with multiple LUNs per target Note: The maximum number of targets + LUN is 256.
LUN mapping (LUN can be moved between iSCSI and FC if supported)
LUN masking Online LUN capacity expansion
|VJBOD Cloud||VJBOD Cloud now supports cloud Volume/LUNs.
VJBOD Cloud now supports one-to-one pairing between cloud volumes/LUNs and local stored spaces.
VJBOD Cloud now supports Amazon S3 Azure, BackBlaze, HuaWei Cloud, Alibaba Cloud, HKT, Google Cloud, OpenStack, RackSpace, Wasabi cloud, IBM cloud object storage service.
VJBOD Cloud now supports local stored mode, which means that data can be stored on the NAS and the data can be backed up to the cloud.
|Notification Center||Added support for sending notifications via SMS center (SMSC) or providers, including Nexmo, Twilio, and Clickatell.
Added Outlook as an SMTP service option.
Added support for sending notifications via instant messaging applications, including Skype and Facebook Messenger.
Added support for Overview and History in Notification Center.
|Power Management||Wake-on-LAN (WoL)
Standby mode for internal drives
Scheduled power on and off
Automatic power on after power recovery
|Access Rights Management||Multiple user creation
User data importing and exporting
User quota management
Local user access control (AFP, CIFS/SMB, FTP, and WebDAV)
|Domain Authentication||Microsoft Active Directory (AD) and domain controller support
LDAP server and client
Domain user login (AFP, CIFS/SMB, FTP, and File Station)
|myQNAPcloud||Free host name registration (DDNS)
Optional myQNAPcloud SSL certificates (DDNS)
Auto router configuration using UPnP
Web-based file manager with HTTPS 2048-bit encryption
|Qsync||File syncing across multiple devices with SSL secure connection
Selective synchronization for specific folders or subfolders
Team folders as file center for better collaboration
File sharing using email links
|Resource Monitor||Monitoring of NAS system resources such as CPU, memory and network
Monitoring of NAS storage resources such as volumes, RAID, and disk activity Monitoring of NAS application resource use
Creation of extra swap space when SSDs are installed
|Helpdesk||Reporting of issues to the QNAP support team, with automatic collection of system information
Remote connection between QNAP support engineers and NAS for issue resolution (with user permission)
|Web Desktop Administration||Multi-window, multitasking system management
Smart toolbar and dashboard for system status display
SNMP versions 2 and 3
|File Server||File sharing across Windows, Mac, and Linux/UNIX
Microsoft networking (CIFS/SMB)
Apple networking (AFP)
NFS version 3/4 services
|FTP Server||FTP, SFTP
FTP over SSL/TLS (explicit FTPS)
|File Station||Integrate with HybridMount which supports File
Cloud Gateway and File Station Mount mode. File Station Mount mode supports: Cloud drive mounting for Google Drive, Dropbox, Microsoft OneDrive, Microsoft OneDrive for Business, HiDrive, Amazon Cloud Drive, Yandex Disk and Box
Remote shared folder mounting (CIFS/SMB, FTP, and WebDAV)
Restore QDFF files and folders with HBS 3
Archiving through iSCSI, USB, DVD and remote NAS
|HBS (Hybrid Backup Sync)||Integrating indexing, transcoding, thumbnail generation, and content management.
New content management design, configuring content sources for QTS multimedia applications.
View the status of multimedia apps and services all on the same screen.
Video transcoding (240p, 360p, 480p, 720p and 1080p resolution)
|QuMagie||Browse photos in timeline view or folder view.
Virtual albums and smart albums.
AI-assisted photo management, classifying people, things, places, etc. Note: QuMagie Core is necessary for AI recognition. Supported on NAS models with 4GB RAM.
|Photo Station||Photo organization by thumbnail, list, timeline, or folder
Virtual and smart albums
Validity control for album sharing
Photo tagging with text, colors, and ratings
|Music Station||Music playing and sharing through web browsers
Music streaming to multiple devices
Changing of album covers through Google search or by uploading photos
Internet radio (MP3)
|Video Station||Video organization by thumbnail, list, timeline, or folder
Virtual and smart collections
Video tagging with text, colors, and ratings
Video link sharing through social media and email
|Virtualization Station||Virtual machine creation (Windows, Linux, Unix, and Android)
Virtual machine importing, exporting, cloning, snapshot capturing, backup, and restoration
Console display using HDMI output (QVM)
HTML5-based shared remote console
|Container Station||Support for LXC and Docker
Application downloading from the built-in Docker Hub Registry
Container importing and exporting
Data distribution using a bar chart
Previews for photos, music, videos, PDFs, Gmail, and others
Advanced search operators and search scope
|QVR Pro||Instant switch between Live and Playback modes
Dynamic and adjustable layouts for camera and E-map views
Qdewarp technique for dewarping fisheye and 360-degree cameras
Region of interest for each channel
|QVR Pro Client (Mobile)||Instant switch between Live and Playback modes
Cross-platform support: Android and iOS
Various advanced monitoring options, including sequential mode, PTZ control, auto cruising, and preset point control
Support for receiving Instant push notifications
|QVR Center||Support for managing up to 128 QVR Pro servers (QVR Pro Gold license required)
Statistical graphics for visualizing event data
Log management for all added servers
Integration with QVR Pro Client for central monitoring across multiple servers
|QVR Guard|| Support for more camera manufacturers and models
Note: To download the Camera Package, go to QVR Pro Plug-in Center.
|QUSBCam2||Support for configuring USB webcams as ONVIF IP cameras (remotely manageable)
Support for monitoring live views (no other apps required)
Support for RTSP
|Surveillance Station||Support for up to 5,000 IP cameras
2 free camera licenses Note: To add more camera channels, you need to purchase licenses from the QNAP License Store.
Instant playback for recent surveillance events
Visual options for e-maps
|QVPN Service||VPN server
Friendly graphical overview page.
Secure remote access with PPTP, L2TP/IPSec, OpenVPN, QBelt(QNAP proprietary) protocol.
Support for a maximum of 100 clients.
|DLNA Server||Support for DLNA/UPnP TVs and players such as PlayStation 4 and Xbox One
Support for CUE indexing file for APE and FLAC
|Q'center (NAS CMS)||Monitoring of multiple NAS devices
Utilization history reports
Unified configuration management
Monitoring of NAS devices behind NAT routers with Connect to Q'center
|Qfinder Pro||QNAP NAS location on the same local network
NAS shared folder mounting
Basic setting configuration (firmware, SMTP server, and network settings)
Storage Plug & Connect (Windows only)
|Chromecast||Video, photo and music streaming to Apple TV (via Qmedia) or Chromecast using the following:
NAS applications: File Station, Music Station, Photo Station, and Video Station
Mobile applications: Qfile, Qmusic, Qphoto, and Qvideo Note: You must install the Media Streaming add-on from App Center
PC-less downloads (BitTorrent, FlashGet, FTP/FTPS, HTTP/HTTPS, QQDL, and Thunder)
BitTorrent: Support for search, magnet links, private trackers, and proxy
|Notes Station 3||Insert Evernote Notes in Notes Station 3
Enable Embedding YouTube video into Notes
Table creation using the insert table editor
|HD (HybridDesk) Station||Photo, video, and music playback on TV through HDMI
Support for Chrome and Firefox
Support for international keyboards and mouse input
User login permissions Note: The decoding capability of the CPU and graphics card may affect playback of some video files.
|Linux Station||Usage of the NAS as a Linux-based computer
Support for Ubuntu 14.04, Ubuntu 16.04 and Ubuntu Kylin 16.04
Application downloading and usage from the Ubuntu Software Center
Remote desktop for remote monitoring and accessing of Ubuntu
|Qcontactz||One-way scheduled sync of contacts from multiple Google accounts
Contact importing from CSV or vCard 3.0 files
Contact exporting to CSV or vCard 3.0 files
Duplicate contact searching and merging
|IFTTT Agent||Daily task automation
Social media data archiving
File synchronization between the NAS and various cloud services
System event notifications on Line, Skype, Gmail, and mobile phones
|Qmiix Agent:||File synchronization between the NAS and various cloud services
View miixes made using the Qmiix web portal that include triggers and actions involving QNAP apps.
Create miixes for web-based and NAS-related apps.
Create miixes on the Qmiix web portal that include File Station, a QNAP app
Multiple Security Policies (Basic/Intermediate/Advanced/Custom).
.Integrates with the Security Advisory service.
Detects and removes malware from your QNAP NAS.
Note: To ensure the security of your NAS, update this app when new versions become available.
|App Center||Official and community software add-ons
Automatic updates and notifications for new versions
Repository for imported third-party content
User-specified volume for storing applications
|General Notes||Designs and specifications are subject to change without notice.
Some features may vary by model.
QTS does not support DRM content and some IPv6 services.
Some data encryption features may be unavailable because of country-specific legislative restrictions.
|Deprecated Features||The following features are deprecated but will continue to function until completely removed in a future release. QNAP recommends planning now for the future removal of support.
Support for wireless ad hoc networks
|LED Indicators||Power/Status, LAN, USB, HDD1-2|
|Buttons||Power, USB copy, Reset|
|Operating temperature||0 - 40 °C (32°F - 104°F)|
|Relative Humidity||5-95% RH non-condensing, wet bulb: 27˚C (80.6˚F)|
|Power Supply Unit||External Power Adapter, 65W, 100-240V|
|Power Consumption: HDD Sleep Mode||8.08 W|
|Power Consumption: Operating Mode, Typical||15.25 W|
|Fan||1 x 70mm|
|Sound Level||16.7 db(A)|
|Kensington Security Slot||Yes|
|Max. Number of Concurrent Connections (CIFS)||800|
|Dimensions (HxWxD)||168 × 105 × 226 mm|
- Ethernet Cable x 1
- AC Adapter
- Power Cord
- Flat head screw (for 3.5" HDD) x8
- Flat head screw (for 2.5" HDD) x6
- Quick Installation Guide (QIG)