What is SSH and why is it important in network security?

SSH stands for Secure Shell. It is a network protocol that allows secure remote access and control of a computer or server over an unsecured network. SSH provides a secure channel for communication by encrypting all data transmitted between the client and server, including passwords and commands.SSH is important in network security for several reasons:Encryption: SSH uses strong encryption algorithms to protect data from unauthorized access or interception. This ensures the confidentiality and integrity of sensitive information transmitted over the network.Authentication: SSH provides various authentication methods, such as passwords, public-key cryptography, and two-factor authentication. These mechanisms ensure that only authorized users can access the remote system, preventing unauthorized access and potential security breaches.Secure Remote Administration: SSH allows system administrators to securely manage and administer remote systems, even over untrusted networks like the internet. It enables secure remote access to servers, routers, switches, and other network devices, reducing the risk of unauthorized access and potential attacks.Port Forwarding: SSH supports port forwarding, which allows secure tunneling of network connections over an SSH session. This feature is crucial for securely accessing services or resources on remote networks, especially when dealing with sensitive data or accessing internal systems from outside the network.Secure File Transfer: SSH includes secure file transfer capabilities, commonly known as SFTP (SSH File Transfer Protocol) or SCP (Secure Copy). These protocols enable secure file transfer between systems, ensuring the confidentiality and integrity of files during transit.Overall, SSH plays a vital role in network security by providing secure remote access, encrypted communication, and secure file transfer capabilities, helping to protect sensitive data and prevent unauthorized access to systems and networks.

How does SSH work and what are its key features in terms of authentication and encryption?

SSH, which stands for Secure Shell, is a network protocol that provides a secure and encrypted way to access and communicate with remote systems over an unsecured network. It is commonly used for remote administration of servers and secure file transfers.Authentication:Public Key Authentication: SSH uses public key cryptography for authentication. The client generates a key pair consisting of a public key and a private key. The client's public key is stored on the remote server, while the private key remains with the client. When the client connects to the server, it proves its identity by signing a challenge with its private key, and the server verifies it using the stored public key.Password Authentication: SSH also supports traditional password-based authentication. The client provides a username and password to authenticate with the server. However, this method is less secure and susceptible to brute-force attacks.Encryption:SSH ensures confidentiality and integrity of data through encryption. It encrypts all communication between the client and server, protecting it from eavesdropping and tampering. The key features of encryption in SSH include:Symmetric Encryption: SSH uses a symmetric encryption algorithm, such as AES (Advanced Encryption Standard), to encrypt the actual data being transmitted. A shared session key is established during the initial connection setup, and this key is used for encrypting and decrypting the data.Asymmetric Encryption: As mentioned earlier, SSH uses public key cryptography for authentication. It also employs asymmetric encryption algorithms, such as RSA or DSA, to securely exchange the session key between the client and server during the connection setup.Integrity Checks: SSH uses cryptographic hash functions, such as SHA-2, to ensure the integrity of transmitted data. Hash functions generate a unique hash value for each piece of data, which is sent along with the data. The recipient can verify the integrity by recalculating the hash value and comparing it with the received value.Forward Secrecy: SSH provides forward secrecy, which means that even if an attacker obtains the server's private key in the future, they cannot decrypt past sessions. Each session in SSH uses a unique session key that is generated for that session only.Overall, SSH provides strong authentication mechanisms and robust encryption techniques to ensure secure and private communication between the client and server.

In what ways does the NAS QNAP Turbo Station TS-877 / TS-877XU utilize SSH protocol to enhance its functionality and secure remote access?

The NAS QNAP Turbo Station TS-877 / TS-877XU utilizes the SSH (Secure Shell) protocol in several ways to enhance its functionality and secure remote access. Here are some of the ways:Secure Remote Access: The SSH protocol allows for secure remote access to the NAS. Users can remotely connect to the NAS using SSH, which encrypts the data transmission, ensuring that sensitive information remains secure.Command Line Interface (CLI): SSH provides a command-line interface to access the NAS. This allows advanced users to execute various commands and perform administrative tasks remotely, providing more flexibility and control over the NAS.Secure File Transfer: SSH protocol supports SFTP (SSH File Transfer Protocol), which enables secure file transfer between the NAS and remote devices. SFTP encrypts the data during transmission, ensuring that files transferred to and from the NAS remain protected.Secure Shell Access: The NAS supports SSH access for authorized users, allowing them to securely access the NAS's operating system. This enables advanced users to perform system-level configurations, troubleshoot issues, and run custom scripts, enhancing the NAS's functionality.Secure Backup and Replication: The NAS can utilize SSH for secure backup and replication. By using SSH, data can be securely transferred between the NAS and remote backup servers or other QNAP NAS devices, ensuring the integrity and confidentiality of the backup data.Secure Remote Management: SSH protocol enables secure remote management of the NAS. Administrators can remotely manage the NAS's settings, services, and applications using SSH, enhancing the convenience and security of managing the device.Overall, the utilization of the SSH protocol in the NAS QNAP Turbo Station TS-877 / TS-877XU enhances its functionality by providing secure remote access, secure file transfer, command-line interface, secure backup and replication, and secure remote management capabilities.

Data Recovery After RAID Array Format on NAS QNAP Turbo Station TS-877 / TS-877XU: What to Do

Name: How to recover data from a QNAP
Uploaded: 2025-10-16T08:53:56+03:00
Description: How to recover data from a QNAP

Has your NAS QNAP Turbo Station TS-877 / TS-877XU suddenly lost its network drive and you’re unsure what to do next? Did the RAID array collapse, making your files inaccessible? Is the device throwing errors during startup? Perhaps you accidentally rebuilt the RAID array or several hard drives failed at the same time?

Data Recovery After RAID Array Format on NAS QNAP Turbo Station TS-877 / TS-877XU: What to Do

Data Recovery Tool

QNAP Turbo Station TS-877 / TS-877XU NAS Data Recovery in 2025

In this step-by-step tutorial, we’ll show you how to rebuild your RAID and recover data from an Turbo Station TS-877 / TS-877XU. We’ll walk through the most common causes of failure and demonstrate proven methods to restore files from a lost or degraded RAID array.

Contents

Why Regular Data Recovery Tools Can’t Restore Files from RAID
Key Information About the NAS QNAP Turbo Station TS-877 / TS-877XU
How to Remove Hard Disks from Your NAS and Connect Them to a PC

RAID Recovery™ 2.8

Recover data from damaged RAID arrays inaccessible from a computer.

Download

Why Regular Data Recovery Tools Can’t Restore Files from RAID

Conventional hard drives store user data by writing it sequentially across the disk surface, which means an entire file is typically located on a single drive. In contrast, when data is written to a RAID array, each file is split into multiple fragments. These fragments are then distributed and written in sequence across all the drives in the array. Depending on the configuration, fragment sizes can range from 2 KB to 2 MB, so every file is physically stored across several disks at once.

This approach significantly increases read and write performance — after all, writing two halves of a 1 GB file to two drives simultaneously is much faster than writing the full 1 GB to a single disk. However, this same mechanism makes file recovery far more complex.

Different RAID levels use different methods to distribute and protect data. On top of that, manufacturers like QNAP often add their own proprietary structures and variations. As a result, data can be written to disks in many different formats, and each requires a specific approach during recovery.

Are there any common mistakes or oversights made by users that can lead to data loss on NAS QNAP Turbo Station TS-877 / TS-877XU devices?

Yes, there are several common mistakes or oversights made by users that can lead to data loss on NAS QNAP Turbo Station TS-877 / TS-877XU devices. Some of these include:

Lack of regular backups: Users often overlook the importance of regular backups, assuming that their data is safe on the NAS device. However, hardware failures, accidental deletions, or other issues can still result in data loss. It is crucial to have a proper backup strategy in place to ensure data protection.
Failure to update firmware: QNAP regularly releases firmware updates that include bug fixes, security patches, and performance improvements. Neglecting to update the firmware can leave the device vulnerable to security threats or software bugs that may result in data loss.
Inadequate RAID configuration: The TS-877 / TS-877XU devices support various RAID configurations for data redundancy and protection. Users may incorrectly configure or set up RAID, leading to data loss in case of a hard drive failure. It is essential to understand the RAID options and choose the appropriate configuration based on your needs.
Improper shutdown or power loss: Abruptly powering off the NAS device or experiencing a power outage while data is being written or accessed can result in data corruption or loss. Users should ensure a proper shutdown procedure and consider using battery backup solutions to prevent sudden power loss.
Insufficient security measures: Weak or easily guessable passwords, lack of two-factor authentication, or failure to implement proper network security measures can make the NAS device vulnerable to unauthorized access or data breaches. It is crucial to use strong passwords, enable two-factor authentication, and regularly review and update security settings.
Neglecting hard drive health monitoring: The NAS device provides tools to monitor the health and status of hard drives. Ignoring these monitoring tools can lead to undetected drive failures or errors, potentially resulting in data loss. Regularly check the health of your hard drives and replace any failing drives promptly.

To minimize the risk of data loss, it is recommended to follow best practices such as regular backups, firmware updates, proper RAID configuration, secure authentication, and monitoring hardware health.

How to Remove Hard Disks from Your NAS and Connect Them to a PC

Although the NAS Turbo Station TS-877 / TS-877XU can be accessed over the network, you still need to remove its hard disks and connect them directly to a Windows PC. Only then can the recovery software properly scan and analyze the drives. Follow these steps:

Power off the NAS and disconnect it from the power source.

WARNING! Before removing any drives, carefully read the device manual. Improper actions may damage both the NAS enclosure and the hard disks in the RAID array.
Remove the hard disks one by one, gently sliding each drive out of its slot. Remember that hard disks are highly sensitive: any impact or drop can cause serious physical damage.
Label each hard disk according to its position inside the NAS. The order of the drives is crucial for correct RAID reconstruction.
Connect the drives to your computer. In this video, we explain which ports you can use to connect hard disks and what to do if your PC does not have enough free connectors.

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How to Order Remote Data Recovery

Step-by-Step Data Recovery with Hetman RAID Recovery

This program restores data from damaged RAID arrays and is fully compatible with QNAP Turbo Station TS-877 / TS-877XU. Each hard disk in the array contains technical metadata describing how files were written. When launched, Hetman RAID Recovery analyzes this metadata, automatically reconstructs the damaged array, and provides access to its contents. After that, you can browse the recovered disk and save your files. The program can also restore files that were accidentally deleted from the network drive.

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How to recover data from a QNAP

Turbo Station TS-877 / TS-877XU has 8 HDD slots, and it supports the following array types:

RAID 50;
RAID 60;
RAID 5;
RAID 6;
RAID 10;
RAID 0;
RAID 1;
JBOD;

NAS supports:

ZFS;
EXT4;
EXT3;
exFAT;
FAT32 (External Disk Only);
NTFS (External Disk Only);
HFS+ (External Disk Read Only);

How to Safely Recover Data from Disk Images

This utility allows you to create a complete copy of a disk and work with the disk image instead of the physical drive. This approach helps protect your data from:

Overwriting during the recovery process;
Additional data loss caused by bad sectors;
User errors.

To create a disk image, follow these steps:

Ensure you have enough free space to store the image. Its size will typically match the size of the original disk.
In the main window, select the target disk and choose Tools - Save Disk. You can also select multiple disks if needed.
When the Image Creation Wizard opens, select whether you want to save the entire disk or only a specific region. Adjust the settings and click Next.
Choose the directory where the image will be saved. You may select any available disk connected to your PC or upload the image via FTP.

Where Are the User’s Files Actually Stored?

The QNAP Turbo Station TS-877 / TS-877XU network-attached storage keeps QTS (QuTS hero) operating system files on a separate RAID 1 (mirrored) array. Usually, all NAS systems create several volumes on every hard disk, and the first of them takes up to 2 Gb of space. This is where operating system files are stored. Other volumes are united into a RAID array where user’s data is written.

RAID Recovery Software: Detailed Comparison

Product	Operating system	RAID controller support	Supported file systems	Virtual RAID controller support	Data recovery from damaged RAID	File preview
Hetman RAID Recovery	Windows, Linux, MacOS	Yes, over 100 controllers	FAT, exFAT, NTFS, ReFS, APFS, HFS+, Ext4, Ext3, Ext2, ReiserFS, Btrfs, VMFS, Hikvision, XFS, UFS, ZFS	Yes	Yes	Yes
DiskInternals RAID Recovery	Windows	Yes, over 10 controllers	FAT, NTFS, Ext2/3/4, HFS+	No	Yes	Yes
R-Studio	Windows, Mac, Linux	Yes, over 20 controllers	FAT, NTFS, Ext2/3/4, HFS+	Yes	Yes	Yes
UFS Explorer RAID Recovery	Windows, Mac, Linux	Yes, over 100 controllers	FAT, NTFS, Ext2/3/4, HFS+	Yes	Yes	Yes
EaseUS Data Recovery	Windows	Yes, over 20 controllers	FAT, NTFS, Ext2/3/4, HFS+	No	Yes	Yes
ReclaiMe Free RAID Recovery	Windows	Yes, over 100 controllers	FAT, NTFS, Ext2/3/4, HFS+	Yes	Yes	Yes

Feedback

We will be happy to answer your questions!

Comments (3)

Hetman Software: Data Recovery 9.08.2022 12:31 #

If you want to ask a question about data recovery, from NAS Turbo Station TS-877 / TS-877XU, feel free to leave a comment!

Reply
Frederick Pitt 17.09.2023 20:54 #

Are there any specific firmware updates or patches recommended for data recovery from NAS QNAP Turbo Station TS-877 / TS-877XU devices?

Reply
- Hetman Software 17.09.2023 22:12 #
  
  Yes, there are firmware updates and patches recommended for data recovery from QNAP Turbo Station TS-877 / TS-877XU devices. QNAP regularly releases firmware updates to address security vulnerabilities, improve performance, and add new features. It is always recommended to keep your NAS firmware up to date to ensure the best possible data recovery experience.
  To check for and download the latest firmware updates for your QNAP Turbo Station TS-877 / TS-877XU, you can visit the QNAP website or use the QTS firmware update feature within the NAS administration interface.
  In addition to firmware updates, QNAP also provides data recovery tools and services. If you encounter any data recovery issues, it is recommended to contact QNAP support for assistance. They can guide you through the recovery process and provide specific patches or tools if needed.
  
  Reply

Post comment

Updated:
16.10.2025 8:53

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Author: Vladimir Artiukh, Technical Writer

Vladimir Artiukh is a technical writer for Hetman Software, as well as the voice and face of their English-speaking YouTube channel, Hetman Software: Data Recovery for Windows. He handles tutorials, how-tos, and detailed reviews on how the company’s tools work with all kinds of data storage devices.

Editor: Oleg Afonin, Technical Writer

Oleg Afonin is an expert in mobile forensics, data recovery and computer systems. He often attends large data security conferences, and writes several blogs for such resources as xaker.ru, Elcomsoft and Habr. In addition to his online activities, Oleg’s articles are also published in professional magazines. Also, Oleg Afonin is the co-author of a well-known book, Mobile Forensics - Advanced Investigative Strategies.

Questions and answers

What is SSH and why is it important in network security?
SSH stands for Secure Shell. It is a network protocol that allows secure remote access and control of a computer or server over an unsecured network. SSH provides a secure channel for communication by encrypting all data transmitted between the client and server, including passwords and commands.
SSH is important in network security for several reasons:
1. Encryption: SSH uses strong encryption algorithms to protect data from unauthorized access or interception. This ensures the confidentiality and integrity of sensitive information transmitted over the network.
2. Authentication: SSH provides various authentication methods, such as passwords, public-key cryptography, and two-factor authentication. These mechanisms ensure that only authorized users can access the remote system, preventing unauthorized access and potential security breaches.
3. Secure Remote Administration: SSH allows system administrators to securely manage and administer remote systems, even over untrusted networks like the internet. It enables secure remote access to servers, routers, switches, and other network devices, reducing the risk of unauthorized access and potential attacks.
4. Port Forwarding: SSH supports port forwarding, which allows secure tunneling of network connections over an SSH session. This feature is crucial for securely accessing services or resources on remote networks, especially when dealing with sensitive data or accessing internal systems from outside the network.
5. Secure File Transfer: SSH includes secure file transfer capabilities, commonly known as SFTP (SSH File Transfer Protocol) or SCP (Secure Copy). These protocols enable secure file transfer between systems, ensuring the confidentiality and integrity of files during transit.
Overall, SSH plays a vital role in network security by providing secure remote access, encrypted communication, and secure file transfer capabilities, helping to protect sensitive data and prevent unauthorized access to systems and networks.
How does SSH work and what are its key features in terms of authentication and encryption?
SSH, which stands for Secure Shell, is a network protocol that provides a secure and encrypted way to access and communicate with remote systems over an unsecured network. It is commonly used for remote administration of servers and secure file transfers.
Authentication:
1. Public Key Authentication: SSH uses public key cryptography for authentication. The client generates a key pair consisting of a public key and a private key. The client's public key is stored on the remote server, while the private key remains with the client. When the client connects to the server, it proves its identity by signing a challenge with its private key, and the server verifies it using the stored public key.
2. Password Authentication: SSH also supports traditional password-based authentication. The client provides a username and password to authenticate with the server. However, this method is less secure and susceptible to brute-force attacks.
Encryption:
SSH ensures confidentiality and integrity of data through encryption. It encrypts all communication between the client and server, protecting it from eavesdropping and tampering. The key features of encryption in SSH include:
1. Symmetric Encryption: SSH uses a symmetric encryption algorithm, such as AES (Advanced Encryption Standard), to encrypt the actual data being transmitted. A shared session key is established during the initial connection setup, and this key is used for encrypting and decrypting the data.
2. Asymmetric Encryption: As mentioned earlier, SSH uses public key cryptography for authentication. It also employs asymmetric encryption algorithms, such as RSA or DSA, to securely exchange the session key between the client and server during the connection setup.
3. Integrity Checks: SSH uses cryptographic hash functions, such as SHA-2, to ensure the integrity of transmitted data. Hash functions generate a unique hash value for each piece of data, which is sent along with the data. The recipient can verify the integrity by recalculating the hash value and comparing it with the received value.
4. Forward Secrecy: SSH provides forward secrecy, which means that even if an attacker obtains the server's private key in the future, they cannot decrypt past sessions. Each session in SSH uses a unique session key that is generated for that session only.
Overall, SSH provides strong authentication mechanisms and robust encryption techniques to ensure secure and private communication between the client and server.
In what ways does the NAS QNAP Turbo Station TS-877 / TS-877XU utilize SSH protocol to enhance its functionality and secure remote access?
The NAS QNAP Turbo Station TS-877 / TS-877XU utilizes the SSH (Secure Shell) protocol in several ways to enhance its functionality and secure remote access. Here are some of the ways:
1. Secure Remote Access: The SSH protocol allows for secure remote access to the NAS. Users can remotely connect to the NAS using SSH, which encrypts the data transmission, ensuring that sensitive information remains secure.
2. Command Line Interface (CLI): SSH provides a command-line interface to access the NAS. This allows advanced users to execute various commands and perform administrative tasks remotely, providing more flexibility and control over the NAS.
3. Secure File Transfer: SSH protocol supports SFTP (SSH File Transfer Protocol), which enables secure file transfer between the NAS and remote devices. SFTP encrypts the data during transmission, ensuring that files transferred to and from the NAS remain protected.
4. Secure Shell Access: The NAS supports SSH access for authorized users, allowing them to securely access the NAS's operating system. This enables advanced users to perform system-level configurations, troubleshoot issues, and run custom scripts, enhancing the NAS's functionality.
5. Secure Backup and Replication: The NAS can utilize SSH for secure backup and replication. By using SSH, data can be securely transferred between the NAS and remote backup servers or other QNAP NAS devices, ensuring the integrity and confidentiality of the backup data.
6. Secure Remote Management: SSH protocol enables secure remote management of the NAS. Administrators can remotely manage the NAS's settings, services, and applications using SSH, enhancing the convenience and security of managing the device.
Overall, the utilization of the SSH protocol in the NAS QNAP Turbo Station TS-877 / TS-877XU enhances its functionality by providing secure remote access, secure file transfer, command-line interface, secure backup and replication, and secure remote management capabilities.