What is SSH and how does it work in the context of network security?

SSH, or Secure Shell, is a cryptographic network protocol that provides a secure way to access and manage remote devices or systems over an unsecured network. It is commonly used for secure remote administration of servers and other network devices.In terms of network security, SSH plays a crucial role by providing the following features:Encryption: SSH uses encryption algorithms to secure the communication between the client and the server. It ensures that the data transmitted over the network cannot be intercepted or read by unauthorized parties.Authentication: SSH supports various authentication methods, including passwords, public key cryptography, and two-factor authentication. This ensures that only authenticated users can access the remote system, preventing unauthorized access.Integrity: SSH uses cryptographic hash functions to ensure the integrity of data during transmission. It detects any modifications or tampering with the data, which helps in preventing attacks like data manipulation or injection.Port Forwarding: SSH allows secure port forwarding, also known as SSH tunneling. It enables users to securely access services on a remote network by forwarding the traffic through an encrypted SSH connection. This helps protect sensitive services that are not directly exposed to the internet.Secure File Transfer: SSH includes a secure file transfer protocol (SFTP) that allows secure file transfer between the client and the server. It ensures that files are transferred securely, protecting them from unauthorized access or interception.Overall, SSH enhances network security by providing secure remote access and secure data transmission, protecting against eavesdropping, unauthorized access, and data tampering.

How does the NAS QNAP IS-400 Pro utilize SSH protocol for remote access and secure file transfers?

The NAS QNAP IS-400 Pro utilizes the SSH (Secure Shell) protocol for remote access and secure file transfers in the following ways:Remote Access: SSH allows users to remotely access the NAS device through a secure encrypted connection. By enabling SSH on the NAS, users can establish a command-line interface (CLI) session with the device from a remote computer. This enables them to execute various commands and manage the NAS remotely.Secure File Transfers: SSH provides a secure method for transferring files between the NAS and remote computers. The NAS supports the Secure File Transfer Protocol (SFTP) and Secure Copy (SCP), both of which utilize SSH for secure file transfers. Users can use SFTP clients or SCP commands to securely transfer files to and from the NAS over an encrypted SSH connection.Encryption and Authentication: SSH ensures the confidentiality and integrity of data transferred between the NAS and remote computers. It encrypts the data using strong encryption algorithms, preventing unauthorized access or interception. Additionally, SSH provides authentication mechanisms, such as password-based authentication or public key authentication, to ensure only authorized users can access the NAS.Port Forwarding: QNAP NAS devices often support SSH port forwarding, which allows users to securely access other services running on the NAS through an encrypted SSH tunnel. This feature enables users to access services like web servers, databases, or other applications hosted on the NAS remotely, without exposing them directly to the internet.Overall, the NAS QNAP IS-400 Pro leverages the SSH protocol to provide secure remote access and file transfers, ensuring data confidentiality, integrity, and authentication.

Can you explain the benefits and potential risks associated with using SSH on the QNAP IS-400 Pro NAS device?

Using SSH (Secure Shell) on the QNAP IS-400 Pro NAS device offers several benefits and potential risks:Benefits:Secure remote access: SSH provides a secure encrypted connection between the client and the NAS device, ensuring data confidentiality and integrity during remote access.Command-line access: SSH allows users to access the NAS device's command-line interface, providing more advanced control and configuration options compared to graphical user interfaces.File transfer: SSH supports secure file transfer between the client and the NAS device using tools like SCP (Secure Copy) or SFTP (SSH File Transfer Protocol).Secure administration: SSH can be used for secure administration tasks, such as configuring network settings, managing user accounts, and performing system maintenance.Potential Risks:Misconfiguration: Incorrectly configuring SSH settings may expose the NAS device to security vulnerabilities, allowing unauthorized access or compromising data.Weak passwords: Weak or easily guessable passwords for SSH authentication can make the NAS device susceptible to brute-force attacks.Exploitable vulnerabilities: If the SSH implementation on the NAS device has any security vulnerabilities, attackers may exploit them to gain unauthorized access or execute malicious commands.Unauthorized access: If SSH access is enabled without proper access controls, unauthorized users may gain access to the NAS device, potentially leading to data breaches or unauthorized actions.To mitigate these risks, it is important to follow best practices:Use strong passwords or consider using SSH key-based authentication instead of passwords.Regularly update the firmware of the NAS device to ensure any SSH vulnerabilities are patched.Disable SSH access when not in use to minimize the attack surface.Implement network-level security measures, such as firewalls, to restrict SSH access to trusted IP addresses or networks.Monitor SSH logs for any suspicious activity or unauthorized access attempts.It is also recommended to consult the QNAP IS-400 Pro NAS device's documentation and security guidelines for specific recommendations and best practices related to SSH usage.

Distinguishing Between Mechanical and Logical Failures in NAS QNAP IS-400 Pro RAID Arrays: Recovery Guide

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 IS-400 Pro 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?

Distinguishing Between Mechanical and Logical Failures in NAS QNAP IS-400 Pro RAID Arrays: Recovery Guide

Data Recovery Tool

QNAP IS-400 Pro 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 IS-400 Pro. 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 IS-400 Pro
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.

How can data fragmentation impact the read and write speeds, and potential data loss on NAS QNAP IS-400 Pro devices?

Data fragmentation can have several impacts on the read and write speeds, as well as potential data loss, on NAS QNAP IS-400 Pro devices:

Reduced read and write speeds: Fragmentation occurs when files are split into multiple fragments and stored in non-contiguous locations on the storage medium. This can lead to slower read and write speeds as the system needs to access multiple fragmented pieces of data instead of a single continuous block. The fragmented data requires additional seek time, which can significantly impact the overall performance of the NAS device.
Increased disk I/O operations: Fragmented data requires more disk I/O operations to access and retrieve the scattered fragments. This increased disk activity can result in slower read and write speeds, as the system needs to perform additional operations to gather all the fragments of a file.
Higher disk wear and tear: Fragmentation can cause excessive disk head movement, leading to increased wear and tear on the hard drives. This can reduce the lifespan of the drives and increase the chances of disk failures, potentially resulting in data loss.
Increased risk of data loss: Fragmentation increases the risk of data loss because fragmented files are more susceptible to corruption or data loss due to disk errors. If a single fragment becomes corrupted or lost, it can render the entire file inaccessible or unusable.

To mitigate these impacts, it is recommended to regularly defragment the data on NAS QNAP IS-400 Pro devices. Defragmentation rearranges the fragmented data into contiguous blocks, improving read and write speeds and reducing the risk of data loss. Additionally, ensuring sufficient free space on the NAS device and regularly monitoring disk health can help minimize the impact of fragmentation and improve overall system performance and data integrity.

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

Although the NAS IS-400 Pro 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 IS-400 Pro. 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

IS-400 Pro has 4 HDD slots, and it supports the following array types:

RAID 6;
RAID 5;
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 IS-400 Pro 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 IS-400 Pro, feel free to leave a comment!

Reply
Eli Brunton 18.09.2023 08:43 #

Is it possible to recover data from a NAS QNAP IS-400 Pro device that has undergone a system update or software upgrade?

Reply
- Hetman Software 18.09.2023 08:59 #
  Yes, it is possible to recover data from a NAS QNAP IS-400 Pro device that has undergone a system update or software upgrade. However, it is important to note that there are certain precautions and steps that need to be followed to ensure successful data recovery.
  Here are some general steps to recover data from a NAS QNAP IS-400 Pro device:
  Stop using the NAS immediately: When you realize that data has been lost or deleted, it is important to stop using the NAS device to prevent any further overwriting of data.
  Contact a professional data recovery service: It is recommended to seek the assistance of a professional data recovery service that specializes in NAS devices. They have the expertise and tools to handle data recovery from NAS devices effectively.
  Provide detailed information: When contacting the data recovery service, provide them with detailed information about the NAS device, the system update or software upgrade that was performed, and any other relevant information. This will help them understand the situation better and provide appropriate solutions.
  Follow the advice of the data recovery service: The data recovery service will guide you through the necessary steps to recover the data. They may ask you to send the NAS device to their facility for analysis and recovery.
  It is important to note that the success of data recovery depends on various factors such as the extent of data loss, the condition of the NAS device, and the actions taken after the data loss. Therefore, it is always recommended to have a backup of important data to avoid such situations.
  Reply

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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 how does it work in the context of network security?
SSH, or Secure Shell, is a cryptographic network protocol that provides a secure way to access and manage remote devices or systems over an unsecured network. It is commonly used for secure remote administration of servers and other network devices.
In terms of network security, SSH plays a crucial role by providing the following features:
1. Encryption: SSH uses encryption algorithms to secure the communication between the client and the server. It ensures that the data transmitted over the network cannot be intercepted or read by unauthorized parties.
2. Authentication: SSH supports various authentication methods, including passwords, public key cryptography, and two-factor authentication. This ensures that only authenticated users can access the remote system, preventing unauthorized access.
3. Integrity: SSH uses cryptographic hash functions to ensure the integrity of data during transmission. It detects any modifications or tampering with the data, which helps in preventing attacks like data manipulation or injection.
4. Port Forwarding: SSH allows secure port forwarding, also known as SSH tunneling. It enables users to securely access services on a remote network by forwarding the traffic through an encrypted SSH connection. This helps protect sensitive services that are not directly exposed to the internet.
5. Secure File Transfer: SSH includes a secure file transfer protocol (SFTP) that allows secure file transfer between the client and the server. It ensures that files are transferred securely, protecting them from unauthorized access or interception.
Overall, SSH enhances network security by providing secure remote access and secure data transmission, protecting against eavesdropping, unauthorized access, and data tampering.
How does the NAS QNAP IS-400 Pro utilize SSH protocol for remote access and secure file transfers?
The NAS QNAP IS-400 Pro utilizes the SSH (Secure Shell) protocol for remote access and secure file transfers in the following ways:
1. Remote Access: SSH allows users to remotely access the NAS device through a secure encrypted connection. By enabling SSH on the NAS, users can establish a command-line interface (CLI) session with the device from a remote computer. This enables them to execute various commands and manage the NAS remotely.
2. Secure File Transfers: SSH provides a secure method for transferring files between the NAS and remote computers. The NAS supports the Secure File Transfer Protocol (SFTP) and Secure Copy (SCP), both of which utilize SSH for secure file transfers. Users can use SFTP clients or SCP commands to securely transfer files to and from the NAS over an encrypted SSH connection.
3. Encryption and Authentication: SSH ensures the confidentiality and integrity of data transferred between the NAS and remote computers. It encrypts the data using strong encryption algorithms, preventing unauthorized access or interception. Additionally, SSH provides authentication mechanisms, such as password-based authentication or public key authentication, to ensure only authorized users can access the NAS.
4. Port Forwarding: QNAP NAS devices often support SSH port forwarding, which allows users to securely access other services running on the NAS through an encrypted SSH tunnel. This feature enables users to access services like web servers, databases, or other applications hosted on the NAS remotely, without exposing them directly to the internet.
Overall, the NAS QNAP IS-400 Pro leverages the SSH protocol to provide secure remote access and file transfers, ensuring data confidentiality, integrity, and authentication.
Can you explain the benefits and potential risks associated with using SSH on the QNAP IS-400 Pro NAS device?
Using SSH (Secure Shell) on the QNAP IS-400 Pro NAS device offers several benefits and potential risks:
Benefits:
1. Secure remote access: SSH provides a secure encrypted connection between the client and the NAS device, ensuring data confidentiality and integrity during remote access.
2. Command-line access: SSH allows users to access the NAS device's command-line interface, providing more advanced control and configuration options compared to graphical user interfaces.
3. File transfer: SSH supports secure file transfer between the client and the NAS device using tools like SCP (Secure Copy) or SFTP (SSH File Transfer Protocol).
4. Secure administration: SSH can be used for secure administration tasks, such as configuring network settings, managing user accounts, and performing system maintenance.
Potential Risks:
1. Misconfiguration: Incorrectly configuring SSH settings may expose the NAS device to security vulnerabilities, allowing unauthorized access or compromising data.
2. Weak passwords: Weak or easily guessable passwords for SSH authentication can make the NAS device susceptible to brute-force attacks.
3. Exploitable vulnerabilities: If the SSH implementation on the NAS device has any security vulnerabilities, attackers may exploit them to gain unauthorized access or execute malicious commands.
4. Unauthorized access: If SSH access is enabled without proper access controls, unauthorized users may gain access to the NAS device, potentially leading to data breaches or unauthorized actions.
To mitigate these risks, it is important to follow best practices:
1. Use strong passwords or consider using SSH key-based authentication instead of passwords.
2. Regularly update the firmware of the NAS device to ensure any SSH vulnerabilities are patched.
3. Disable SSH access when not in use to minimize the attack surface.
4. Implement network-level security measures, such as firewalls, to restrict SSH access to trusted IP addresses or networks.
5. Monitor SSH logs for any suspicious activity or unauthorized access attempts.
It is also recommended to consult the QNAP IS-400 Pro NAS device's documentation and security guidelines for specific recommendations and best practices related to SSH usage.