cPanel Disk Space Issues can disrupt your website’s normal operation by preventing file uploads, email delivery, backups, and other essential hosting tasks. One common cause is the “Other Usage” section in cPanel, which may show a significant amount of storage being used without clearly indicating what is consuming the space. This often makes it difficult for website owners to identify the root cause of the problem.

The “Other Usage” category typically includes hidden files, log files, temporary cache, system-generated files, and items stored in the Trash that may not be immediately visible through the File Manager. Understanding what contributes to this storage usage is the first step toward managing your hosting account more effectively. In this guide, we’ll explain what “Other Usage” means, explore the common reasons behind cPanel Disk Space Issues, and discuss what to look for before making any changes to your hosting environment.

Common Signs of cPanel Disk Space Issues

Explain symptoms like:

• Unable to upload files
• Emails not being delivered
• Backup failures
• WordPress update errors
• “Disk quota exceeded” messages
• Website performance issues

Prerequisites

Before you begin, make sure you have:

• Access to your cPanel account to review storage usage.
• A recent backup to prevent accidental data loss.
• SSH access (if provided by your hosting provider) for advanced investigation.
• Appropriate permissions to manage hosting files.

What Causes “Other Usage”?

The Other Usage section may include:

• Large log files generated by applications or websites.
• Files stored in the Trash folder.
• Temporary application files
• Failed backup archives
• Website migration files
• Session files
• Cache generated by CMS applications
• Large archived log files
• Hidden files (also known as dotfiles).
• Temporary cache files.
• System-managed user files located in directories such as /var and /usr (depending on your hosting environment).
• Old backup files that are no longer needed.

Since these files are not always visible in the Disk Usage interface, they can consume a significant amount of storage without user noticing.

Steps to Resolve Disk Space Issues

Step 1: Clear Unnecessary Log Files

Log files can grow over time and occupy a large amount of storage. Review old or unnecessary logs and remove them if they are no longer required for troubleshooting.

Step 2: Empty the Trash

Files moved to the Trash still consume disk space until they are permanently deleted. Open the File Manager, review the Trash folder, and empty it to free up storage.

Step 3: Check Hidden Files

Enable Show Hidden Files (dotfiles) in File Manager. Review hidden files carefully and remove only those that are safe to delete.

Step 4: Review System-Managed User Files

Some hosting environments store user-related files in directories such as /var and /usr. If you have the required permissions, review these locations and remove unnecessary files with caution. If you don’t have necessary permissions then ask your hosting provider to do it. Avoid deleting system files unless you are certain they are no longer needed.

Step 5: Remove Old Backups and Cache Files

Delete outdated backup archives and clear unnecessary cache files created by your applications. This can free a significant amount of disk space.

Step 6: Verify Disk Usage

After cleaning up, revisit the Disk Usage page in cPanel to confirm that the available storage has increased and the “Other Usage” value has decreased.

Conclusion

The “Other Usage” section in cPanel can sometimes hide the actual cause of high disk consumption, but resolving the issue is usually straightforward. Clearing old logs, emptying the Trash, checking hidden files, removing outdated backups, and reviewing system-managed files can help reclaim valuable storage space. Regularly monitoring disk usage and cleaning unnecessary files will help keep your hosting account running smoothly and prevent future storage-related problems.

Need Help Resolving cPanel Disk Space Issues?

If your hosting account continues to experience storage issues or the “Other Usage” category keeps growing without a clear reason, our experienced engineers can help identify the underlying cause and recommend the right solution. From ongoing server monitoring to complete cPanel Infrastructure Management, Skynats provides 24/7 expert support to keep your hosting environment running smoothly.

👉 Explore our Professional cPanel Management or Contact Us to speak with our server management experts.

The post How to Resolve cPanel Disk Space Issues: Understanding “Other Usage” appeared first on Server Management Services | Cloud Management | Skynats.

Quick Answer

AWS CloudFormation Setup is the process of creating, deploying, and managing AWS infrastructure using reusable YAML or JSON templates.CloudFormation is widely used by organizations offering managed cloud infrastructure services to automate scalable and repeatable cloud deployments. Instead of manually configuring AWS resources, CloudFormation automates provisioning, updates, and deletions while maintaining consistency, reducing human error, and simplifying infrastructure management.

What Is AWS CloudFormation?

AWS CloudFormation is Amazon Web Services’ Infrastructure as Code (IaC) service that automates cloud infrastructure deployment. Organizations using AWS cloud management can leverage CloudFormation to standardize, provision, and manage AWS resources efficiently.. It enables developers and system administrators to define cloud infrastructure using code rather than configuring resources manually through the AWS Management Console.

A CloudFormation template acts as a blueprint that describes the AWS resources your application requires. When you deploy the template, AWS automatically creates the resources in the correct order while resolving dependencies between them.

This approach makes deployments:

• Faster
• Consistent
• Repeatable
• Version-controlled
• Easier to scale

Whether you’re deploying a single Amazon S3 bucket or an entire production environment, CloudFormation helps automate the entire process.

Why Use AWS CloudFormation?

Managing AWS infrastructure manually becomes increasingly difficult as environments grow.

CloudFormation simplifies infrastructure management by offering:

• Infrastructure as Code (IaC)
• Automated resource provisioning
• Consistent deployments across environments
• Easy rollback during failures
• Version-controlled infrastructure
• Simplified disaster recovery
• Reduced operational errors

For organizations managing multiple AWS environments, CloudFormation significantly improves operational efficiency and deployment reliability.

How AWS CloudFormation Works

CloudFormation follows a simple workflow:

1. Write a YAML or JSON template.
2. Upload the template to AWS.
3. Create a CloudFormation Stack.
4. AWS provisions resources automatically.
5. Monitor deployment progress.
6. Update infrastructure when needed.
7. Delete the stack when resources are no longer required.

This workflow ensures infrastructure remains reproducible and easy to manage throughout its lifecycle.

Step 1: Sign In to the AWS Management Console

Log in to your AWS account.

1. Open the AWS Management Console.
2. Enter your credentials.
3. In the search bar, type CloudFormation.
4. Select AWS CloudFormation from the services list.

You’ll be redirected to the CloudFormation dashboard, where you can create and manage infrastructure stacks.

Step 2: Create a CloudFormation Template

A template defines the infrastructure you want AWS to deploy.

Create a file named:

s3-bucket.yaml

AWSTemplateFormatVersion: '2010-09-09'
Description: Create an Amazon S3 Bucket

Resources:
  DemoBucket:
    Type: AWS::S3::Bucket

Save the file locally.

Understanding the Template

This template contains:

• AWSTemplateFormatVersion – Specifies the template version.
• Description – Explains the purpose of the template.
• Resources – Lists the AWS resources to create.
• AWS::S3::Bucket – Creates a new Amazon S3 bucket.

Although simple, this demonstrates the core concept of Infrastructure as Code.

Step 3: Create a CloudFormation Stack

A Stack is a collection of AWS resources managed together.

To create one:

1. Open the CloudFormation console.
2. Click Create Stack.
3. Choose With new resources (Standard).
4. Under Specify template, select Upload a template file.
5. Upload s3-bucket.yaml.
6. Click Next.

For beginners, uploading a template file is the easiest approach.

Step 4: Specify Stack Details

Provide the required configuration.

Example:

Leave the remaining options unchanged for this tutorial.

Click Next.

Step 5: Configure Stack Options

CloudFormation offers several optional settings, including:

• Tags
• IAM permissions
• Rollback configuration
• Notifications
• Stack policies
• Monitoring options

For a basic deployment, you can keep the default values.

Click Next.

Step 6: Review and Create the Stack

Review all configuration settings carefully before deployment.

Once verified:

1. Review the template.
2. Confirm the stack settings.
3. Click Submit.

CloudFormation immediately begins provisioning your infrastructure.

Step 7: Monitor Stack Creation

You can monitor deployment progress from the Stacks page.

Select your stack to view:

• Events
• Resources
• Outputs
• Template
• Parameters

The Events tab displays every action CloudFormation performs during deployment.

Deployment completes successfully when the status changes to:

CREATE_COMPLETE

After deployment:

1. Open the Resources tab.
2. Locate the Amazon S3 bucket.
3. Open the Amazon S3 Console.
4. Verify that the bucket has been created successfully.

This confirms that CloudFormation deployed the infrastructure defined in your template.

Updating a CloudFormation Stack

One of CloudFormation’s biggest advantages is that infrastructure updates are automated.

To update a stack:

1. Modify your template.
2. Select the existing stack.
3. Click Update.
4. Upload the revised template.
5. Review the proposed changes.
6. Submit the update.

CloudFormation only modifies the resources that require changes, minimizing downtime and reducing unnecessary updates.

Deleting a CloudFormation Stack

When infrastructure is no longer needed, CloudFormation can clean it up automatically.

Steps:

1. Select the stack.
2. Click Delete.
3. Confirm deletion.

CloudFormation removes all associated resources unless a resource has a retention policy configured.

Automatic cleanup helps prevent unused resources from generating unnecessary AWS costs.

CloudFormation Best Practices

To build reliable and maintainable infrastructure, follow these best practices:

Use Version Control

Store CloudFormation templates in Git to track changes and collaborate effectively.

Organize Templates

Break large deployments into nested stacks or reusable modules for easier management.

Validate Templates

Use AWS template validation tools before deployment to detect syntax issues early.

Implement Change Sets

Review infrastructure changes before applying them to production environments.

Apply Least Privilege Access

Grant only the IAM permissions required to deploy and manage CloudFormation stacks.

Add Parameters and Outputs

Parameters make templates reusable, while Outputs simplify integration with other AWS services.

Monitor Stack Events

Regularly review deployment events to identify errors and troubleshoot failed deployments quickly.

Common CloudFormation Issues and Troubleshooting

Understanding these common issues can significantly reduce deployment time and improve operational reliability.

Real-World Example

Imagine your development team needs identical environments for development, testing, and production.

Instead of manually configuring hundreds of AWS resources each time, you create one CloudFormation template and deploy it across all environments. This ensures consistency, reduces configuration drift, and allows infrastructure changes to be version-controlled alongside application code.

This Infrastructure as Code approach is widely adopted by DevOps teams to improve scalability and operational efficiency.

Conclusion

AWS CloudFormation Setup provides a reliable and repeatable way to deploy AWS infrastructure using Infrastructure as Code. By defining resources in YAML or JSON templates, organizations can automate deployments, maintain consistent environments, reduce manual errors, and simplify ongoing infrastructure management.

Whether you’re provisioning a single Amazon S3 bucket or deploying a complex cloud architecture, CloudFormation helps standardize deployments and supports modern DevOps practices through automation and version control.

The post AWS CloudFormation Setup Guide: Create & Manage Stacks appeared first on Server Management Services | Cloud Management | Skynats.

In this guide, you’ll learn how to install Dokploy on Ubuntu Server, configure the dashboard, and secure your deployment environment for production use.

Quick Answer

Dokploy can be installed on an Ubuntu server using a single installation script. The installer automatically sets up Docker, Docker Swarm, and Traefik, allowing you to manage and deploy applications through an easy-to-use web dashb

Installation command:

curl -sSL https://dokploy.com/install.sh | sh

http://YOUR_SERVER_IP:3000

Dokploy is an open-source application deployment platform designed for developers and DevOps teams who want complete control over their infrastructure.

It simplifies application deployment by providing a web-based interface that integrates with:

• Docker
• Docker Swarm
• Traefik
• Git repositories
• SSL certificate automation

Many developers consider Dokploy a self-hosted alternative to:

• Heroku
• Vercel
• Netlify

Unlike managed platforms, Dokploy allows you to host applications on your own VPS while maintaining full infrastructure control.

Why Use Dokploy?

Dokploy offers several advantages for developers and businesses:

Benefits of Dokploy

• Simple installation process
• Open-source and self-hosted
• Docker-native deployment
• Built-in reverse proxy management
• Automated SSL certificate support
• Multi-application management
• Resource-efficient architecture
• Beginner-friendly dashboard

For teams looking to reduce hosting costs while maintaining deployment flexibility, Dokploy can be an excellent choice.

Prerequisites

Before installing Dokploy, make sure you have the following:

• A Linux VPS server (Ubuntu, Debian, Fedora, or CentOS)
• Minimum 2GB RAM and 30GB storage recommended
• Root or sudo access
• Open ports:
  • 80 (HTTP)
  • 443 (HTTPS)
  • 3000 (Dokploy dashboard)
• Basic knowledge of Linux terminal commands

Dokploy supports several Linux distributions, here we are using Ubuntu 24 for installing.

How to Install Dokploy on Ubuntu Server

Step 1: Connect to Your Server

Log in to your Ubuntu VPS using SSH.

ssh root@your-server-ip

your-server-ip

with your actual server IP address.

Step 2: Update the Server

Before installing any software, update your system packages.

apt update && apt upgrade -y

curl -sSL https://dokploy.com/install.sh | sh

http://your-server-ip:3000

docker ps

http://your-server-ip:3000

systemctl status docker

ss -tulpn

docker --version

http://your-server-ip:3000

https://deploy.example.com

The post How to Install Dokploy on Ubuntu Server appeared first on Server Management Services | Cloud Management | Skynats.

This happens because CentOS 7 End of Life (EOL) was reached on July 1, 2024. The good news is that the issue can still be fixed temporarily by switching to the CentOS Vault repositories.

Quick Answer

The error occurs because CentOS 7 reached End of Life (EOL) on July 1, 2024, and the official mirror repositories are no longer maintained. To restore package management functionality, update your repository configuration to use CentOS Vault repositories hosted on vault.centos.org.

While this solution allows yum to function again, it is only a temporary workaround. Migrating to a supported operating system such as AlmaLinux or Rocky Linux is strongly recommended.
If your applications are hosted on dedicated infrastructure, a managed dedicated server environment can simplify migration and long-term maintenance.

What Is the CentOS 7 Mirrorlist Error?

The CentOS 7 mirrorlist error occurs when the system attempts to retrieve package information from the official CentOS mirror network.

Since CentOS 7 is now EOL, the standard repositories hosted through mirrorlist.centos.org are no longer available, causing package installation and update operations to fail.

Common symptoms include:

• yum update failures
• Package installation errors
• cPanel update issues
• MultiPHP Manager repository errors
• Failed dependency checks

Why This Error Happens

CentOS 7 repositories are no longer hosted on mirrorlist.centos.org. Since the operating system is now unsupported, package updates and validations stop working unless the repository configuration is changed to use vault.centos.org.
Unsupported operating systems often require additional monitoring, patch management, and server optimization to maintain stability.

Expert Insight

In managed server environments, this issue has become one of the most common support requests for legacy CentOS 7 systems. While switching to Vault repositories restores package access, it does not provide new security patches. Organizations running production workloads should plan a migration strategy immediately.

Prerequisites

Before starting, make sure you have:

• Root or sudo access to the server
• A CentOS 7 system
• Basic knowledge of Linux commands
• Internet connectivity

Step-by-Step Fix

Step 1: Backup the Existing Repository File

Run the following command to create a backup:

This allows you to restore the original configuration if needed.

Step 2: Edit the Repository File

Open the repository file using a text editor:

Replace the existing content with the following:

Save the file and exit.

Step 3: Clean and Rebuild Yum Cache

Run:

This refreshes the repository cache and allows yum to work again.

Verify the Repository

Test whether the fix worked:

If no mirrorlist errors appear, the repository issue has been resolved successfully.

Common Issues After Applying the Fix

Repository Still Not Working

Check DNS connectivity:

ping vault.centos.org

Update CA certificates:

yum update ca-certificates

Run:

scripts/upcp --force

Best Practices for Servers Still Running CentOS 7

Although Vault repositories restore package availability, they should only be considered a short-term solution.

Recommended actions:

1. Audit all CentOS 7 servers.
2. Identify critical applications and dependencies.
3. Create full system backups.
4. Test migration in a staging environment.
5. Migrate to a supported operating system.

Popular alternatives include:

• AlmaLinux
• Rocky Linux
• CloudLinux
• Enterprise Linux distributions

Should You Continue Using CentOS 7?

Only temporarily.
Because CentOS 7 no longer receives security updates, running it in production increases security and compliance risks.

Recommended Approach

Use the Vault repository fix to regain package management functionality, then schedule a migration to a supported operating system as soon as possible.

Conclusion

The CentOS 7 mirrorlist error occurs because CentOS 7 has reached End of Life and the standard repositories are no longer available through mirrorlist.centos.org.

By updating your repository configuration to use vault.centos.org, you can restore yum update functionality and continue managing packages. However, this is only a temporary workaround. For long-term security, stability, and compliance, migrating from CentOS 7 to a supported operating system such as AlmaLinux or Rocky Linux should be your next priority.

The post How to Fix “Could not retrieve mirrorlist” Error on CentOS 7 appeared first on Server Management Services | Cloud Management | Skynats.

That gap between “I clicked save” and “everyone on the internet sees the new record” is DNS propagation, and the only way to truly know where you stand is to query DNS servers across the globe and compare what each one is returning.

That’s exactly why we built KnowDNS — a free, fast, and visually clean global DNS propagation checker. In this guide, we’ll walk through what DNS propagation actually is, why a propagation checker is non-negotiable for anyone running a website, and how KnowDNS helps you verify DNS changes across dozens of locations in seconds.

What Is DNS Propagation?

DNS propagation is the time it takes for changes to a domain’s DNS records to be updated and reflected across DNS servers worldwide. When you modify a record — say, change your A record to a new server IP — that change doesn’t reach the entire internet instantly. Every resolver, ISP, and recursive DNS server has its own cache, and each cache only refreshes after its TTL (Time To Live) expires.

The result: for a window of time, different users in different countries may resolve your domain to different IP addresses. Some see the new server, some still see the old one.

Globally, DNS propagation typically takes anywhere from a few minutes to 48 hours, depending on:

• The TTL value set on the record
• The caching behavior of upstream resolvers (Google DNS, Cloudflare, ISP resolvers)
• Whether you changed nameservers at the registrar level or just records at the DNS host
• Geographic distribution of resolvers

Until propagation completes, you can’t be sure that every visitor is hitting your new infrastructure — which is why a DNS propagation checker is the single most useful tool a sysadmin, developer, or website owner can keep bookmarked.

Why You Need a DNS Propagation Checker

Manually querying DNS from your own machine only tells you what your resolver is returning. It says nothing about what someone in Tokyo, Frankfurt, or São Paulo is seeing. To diagnose propagation issues, you need lookups from multiple geographic locations at once.

A good DNS propagation checker like KnowDNS solves that by:

• Querying public and regional DNS resolvers from dozens of locations in parallel
• Showing you exactly which servers have picked up the new record and which haven’t
• Letting you check every major record type — A, AAAA, CNAME, MX, NS, TXT, SOA, and more
• Returning results in real time, with no caching from previous queries

Whether you’re migrating a website, configuring email (SPF, DKIM, DMARC TXT records), launching a new domain, or troubleshooting why “the site is down for some users,” a propagation checker tells you whether DNS is the culprit — or whether you can rule it out and look elsewhere.

Introducing KnowDNS — Your Free Global DNS Propagation Checker

KnowDNS is a free, browser-based DNS propagation checker built for speed, accuracy, and clarity. No login required, no rate limits for casual use, no clutter. Just type in a domain, pick a record type, and get a clear, side-by-side view of how DNS resolves from locations around the world.

Key Features of KnowDNS

• Global lookup coverage — Query DNS resolvers from multiple continents in a single check, so you see propagation status across North America, Europe, Asia, South America, Africa, and Oceania.
• Support for all major DNS record types — A, AAAA, CNAME, MX, NS, TXT, SOA, PTR, and more. Verify everything from your website’s IP address to your email’s SPF and DKIM records.
• Real-time results — Every lookup is performed live against the resolver, not pulled from a stale cache, so you see exactly what each location is returning right now.
• Clean, scannable interface — Results are presented in a layout designed for quick visual scanning, making it easy to spot a single outlier resolver that hasn’t yet updated.
• No registration, no paywall — KnowDNS is free to use, with no account required for the standard propagation check.
• Mobile-friendly — Check DNS on the go, straight from your phone, when something breaks at 2 AM and you’re not at your desk.

How Long Does DNS Propagation Take?

The short answer: usually 1 to 4 hours for most changes, up to 48 hours in worst-case scenarios. The longer answer depends on a few variables.

TTL (Time To Live) is the single biggest factor. TTL is set on each DNS record and tells resolvers how long to cache the answer. If your TTL was 3600 seconds (1 hour) before you made the change, resolvers around the world will hold onto the old value for up to an hour after you change it. If your TTL was 86400 (24 hours), you’re potentially looking at a full day.

Pro tip: If you know a DNS change is coming, lower the TTL on the affected records to 300 seconds (5 minutes) at least 24 hours before the change. This shortens the cache window and dramatically reduces propagation delay when the actual change goes live.

Nameserver (NS record) changes at the registrar level tend to propagate more slowly than record changes within an already-active DNS zone, because they involve TLD-level updates.

ISP-level caching can occasionally extend propagation beyond the TTL, especially for residential ISPs that aggressively cache to reduce upstream load. This is rare but real, and it’s exactly the kind of thing a global checker like KnowDNS surfaces — you’ll see one or two resolvers stubbornly returning the old value while everyone else has updated.

Why Choose KnowDNS Over Other DNS Checkers?

There are several DNS propagation checkers floating around the web, and most of them work. KnowDNS was built with three priorities that we felt were missing or poorly executed elsewhere:

1. Speed. Lookups complete in a few seconds, not 30+ seconds with a spinning wheel.
2. A clean interface that doesn’t fight you. No interstitial ads in the middle of results, no popups, no upsells. Just the answer.
3. Accuracy via live queries. Some checkers cache their own results to reduce backend load. KnowDNS performs fresh lookups every time, so what you see is what’s resolving right now.

Whether you’re a developer, a sysadmin, a hosting reseller, or a small business owner who just wants to know whether your domain change has finished propagating, KnowDNS is built to give you a straight, fast, accurate answer.

Bookmark it now: https://www.knowdns.com/

DNS is one of those quiet pieces of internet plumbing that nobody thinks about — until it breaks, and then it’s the only thing anyone thinks about. A reliable DNS propagation checker is one of the lowest-effort, highest-leverage tools you can keep in your back pocket.

Whether you’re rolling out a new website, migrating servers, fixing email deliverability, or just confirming a quick A record change, KnowDNS gives you a clear, global, real-time view of where your DNS stands.

Try it out the next time you make a DNS change. Bookmark it. Share it with your team. And if your DNS looks healthy but your servers still aren’t behaving the way you expect them to, Skynats’ server management team is just a click away.

Check your DNS propagation now → https://www.knowdns.com/

The post How to Check DNS Propagation Worldwide in Real Time appeared first on Server Management Services | Cloud Management | Skynats.

If you operate Linux servers — and especially if you run multi-tenant hosting, container build farms, CI/CD runners, or any environment where untrusted users can land a shell — this advisory is for you.

At Skynats, our server management and security operations teams are actively patching customer infrastructure against Dirty Frag right now. This article breaks down what the vulnerability is, who it affects, and exactly what you need to do today.

What Is the Dirty Frag Vulnerability?

Dirty Frag is the nickname given to a chain of two Linux kernel local privilege escalation (LPE) flaws discovered by security researcher Hyunwoo Kim (@v4bel) and disclosed on May 7, 2026:

• CVE-2026-43284 — xfrm-ESP Page-Cache Write (in the IPsec ESP subsystem)
• CVE-2026-43500 — RxRPC Page-Cache Write (in the RxRPC / Andrew File System protocol)

Both vulnerabilities allow an attacker to write into Linux kernel page-cache memory that the kernel does not exclusively own. By chaining the two primitives, an attacker can corrupt sensitive system files in memory and escalate from any unprivileged shell account to full root privileges on virtually every modern Linux distribution.

Dirty Frag is the spiritual successor to Copy Fail (CVE-2026-31431), which was disclosed just weeks earlier. Critically, the popular algif_aead blacklist mitigation that many teams deployed for Copy Fail does not stop Dirty Frag.

Severity and Impact

lsmod | grep -E "esp4|esp6|ipcomp4|ipcomp6|rxrpc"

uname -r

The post Dirty Frag Vulnerability: Critical Linux Kernel Flaw Hands Root Access to Local Attackers (CVE-2026-43284 & CVE-2026-43500) appeared first on Server Management Services | Cloud Management | Skynats.

The post Server Management Services | Why CVE-2026-41940 Proves You Need Skynats appeared first on Server Management Services | Cloud Management | Skynats.

To help system administrators, DevOps engineers, and security teams quickly determine whether their infrastructure is exposed, Skynats has released a free Copy Fail vulnerability scanner to help you confirm your exposure in seconds. In this post, we’ll break down what Copy Fail is, why it matters, and how our new tool helps you confirm — in seconds — whether your kernel is at risk.

What Is the Copy Fail Vulnerability?

Copy Fail is a logic flaw in the Linux kernel’s cryptographic subsystem, specifically inside the `algif_aead` module of the AF_ALG (userspace crypto) interface. The bug allows an unprivileged local user to perform a precise, controlled four-byte write into the kernel’s in-memory page cache of any readable file — including `setuid` binaries such as `/usr/bin/su`.

The implications are severe:

1. Reliable root escalation. Unlike past kernel exploits such as Dirty COW or Dirty Pipe, Copy Fail is not a race condition. It is a deterministic, straight-line logic bug that requires no retries and no timing tricks.
2. Tiny exploit surface. The published proof-of-concept is a 732-byte Python script that uses only standard library modules. There are no compiled payloads, no per-distribution offsets, and no dependency on specific kernel versions.
3. Universal impact. The same script works across Ubuntu, Amazon Linux, RHEL, SUSE, and any other distribution running an affected kernel — essentially every mainstream Linux build since 2017.
4. Container escape risk. In multi-tenant environments, Kubernetes clusters, and CI/CD runners, Copy Fail can be chained with container footholds to escape into the host.

The vulnerability has already been added to the CISA Known Exploited Vulnerabilities (KEV) catalog, and security researchers expect threat actor adoption to accelerate rapidly now that the PoC is public.

Why You Should Care — Even If You “Just Run a Web Server”

Many administrators dismiss local privilege escalation flaws as low priority because they require existing access. That assumption no longer holds. Modern attack chains routinely combine an initial foothold — a compromised SSH key, a vulnerable web application, a malicious npm package in CI, or a rogue container — with a kernel LPE to gain full root control.

Some scenarios where Copy Fail becomes catastrophic:

1. Shared hosting and VPS environments. Any tenant with shell access can elevate to root and read every other tenant’s data.
2. Kubernetes clusters. A single compromised pod can escape to the host node, then pivot across the cluster.
3. CI/CD runners. Untrusted pull requests executing build jobs can root the runner and steal secrets or sign malicious artifacts.
4. Bastion hosts and developer machines. Any low-privilege account becomes a gateway to total compromise.

Introducing the Skynats Copy Fail Vulnerability Scanner

We built the Skynats Copy Fail Scanner to give you an immediate, no-friction answer to the most important question right now:

Is the kernel I’m running today vulnerable to CVE-2026-31431?

The tool is browser-based, requires no installation, and does not collect or transmit any system data beyond the kernel version string you enter. Here’s how it works:

How to Use the Scanner

1. Get your kernel version. On the Linux server you want to check, run:
2. uname -r
3. This will output something like `5.15.0-105-generic` or `4.18.0-553.el8.x86_64`.
4. Open the scanner. Navigate to https://www.skynats.com/tools/copy-fail
5. Paste the kernel version into the input field and click Scan Server.
6. Review the result. The scanner cross-references your version against our continuously updated global vulnerability database, which tracks patched versions for every major distribution branch — Ubuntu, RHEL/CentOS/AlmaLinux/Rocky, SUSE/openSUSE, Debian, Amazon Linux, and upstream stable kernels. You’ll instantly see whether your kernel is vulnerable, partially mitigated, or already patched.

The tool also returns:

1. The safe patch version for your kernel branch.
2. A list of official vendor advisories with direct links.
3. Guided mitigation steps tailored to your distribution.
4. Information on KernelCare live patching for environments where rebooting is not an option.

Beyond the Scan — How Skynats Can Help

If your scan result returned a vulnerable verdict and you need help patching at scale, Skynats provides the engineering muscle to remediate quickly without disrupting production:

Our team is actively assisting clients across AWS, GCP, Azure, OVHcloud, Hetzner, and bare-metal environments with Copy Fail remediation right now. If you need a hand, we’re available 24/7.

Open the Scanner Now

Need urgent help with Copy Fail remediation? Book a free consultation or open a ticket and our engineers will respond within minutes.

The post Copy Fail Vulnerability Scanner: Check Your Linux Kernel for CVE-2026-31431 appeared first on Server Management Services | Cloud Management | Skynats.

Postfix is widely used to send and receive emails in Linux environments. One of the most common issues administrators face is queued mail in Linux servers, where emails get stuck and are not delivered on time.

Managing email servers effectively is crucial, and many businesses rely on Linux server management services to ensure smooth and secure mail delivery.

Queued mail issues in Linux servers usually occur due to high server load, network problems, or misconfigured Postfix settings. You can fix them by checking the mail queue using postqueue, flushing stuck emails, and verifying server configuration.

A queued email means the message has not yet been delivered and is waiting for processing. This can delay communication and affect system performance. Understanding how mail queues work and how to fix issues is essential for maintaining a healthy mail server.

What is a Mail Queue?

A mail queue in Linux is a temporary storage system where emails are held before delivery. In Postfix, emails pass through different queues such as:

• Incoming queue
• Active queue
• Deferred queue
• Hold queue

These queues help manage email delivery efficiently and retry sending messages if initial attempts fail.

Why Emails Get Queued

Emails may get queued due to several reasons:

• High server load
• Network connectivity issues
• Incorrect recipient address
• Temporary rejection from recipient server
• Misconfigured mail server settings

Security restrictions and firewall configurations, often covered in Linux server security best practices, can also impact email delivery.

Prerequisites

Before fixing queued mail issues, ensure you have:

• SSH access to the server
• Administrative or root privileges
• Postfix installed and running

Steps to Fix Queued Mail Problem

Step 1: Check the Mail Queue

Use the following command to view queued emails:

postqueue -p

This shows details like queue ID, sender, and recipient.

Step 2: Identify the Issue

Look for patterns such as:

• Repeated delivery failures
• Incorrect email addresses
• Delayed or deferred messages

Understanding the root cause helps prevent recurring issues.

Step 3: Flush the Mail Queue

To force delivery of queued emails, run:

postqueue -f

This command retries sending all emails in the queue. Use it carefully, as frequent use may impact performance.

Step 4: Remove Problematic Emails (Optional)

To delete a specific email:

postsuper -d <queue_id>

To delete all queued emails:

postsuper -d ALL

This helps clear stuck or unwanted messages.

Step 5: Verify Server Configuration

Check the following, including security layers like SELinux configuration in Linux:

• SMTP configuration
• DNS settings (MX records)
• Server connectivity

Misconfigurations are a common cause of persistent mail queue issues.

Real-World Insight

In production environments, queued mail problems often occur due to:

• Blacklisted IP addresses
• Reverse DNS misconfiguration
• Firewall restrictions blocking SMTP ports

Regular monitoring and log analysis (/var/log/maillog) can help detect issues early.

Key Takeaways

• Queued mail means emails are waiting for delivery
• Common causes include server load, DNS issues, and misconfiguration
• Use postqueue -p to check queue status
• Use postqueue -f to retry sending emails
• Use postsuper to remove problematic messages
• Proper configuration prevents most issues

Conclusion

Queued mail issues are common in Linux mail servers but can be resolved quickly with the right approach. By understanding how Postfix queues work and using commands like postqueue and postsuper, administrators can restore email flow efficiently.

Regular monitoring, proper DNS setup, and optimized server configuration are key to avoiding future mail delivery issues.

If you’re facing persistent email delivery issues or need expert help managing your Linux servers, professional server management services can ensure reliable and secure mail operations.

The post How to Fix Queued Mail Issues in Linux Servers (Postfix) appeared first on Server Management Services | Cloud Management | Skynats.

While working with FTP (such as FileZilla) on Linux servers, you may encounter a situation where:

• You can upload new files
• You can create directories
• But you cannot overwrite existing files, receiving a “permission denied” error

This issue usually occurs due to ACL (Access Control List) restrictions, where the ACL mask limits write permissions—even if standard Linux permissions (chmod/chown) appear correct.

At first glance, standard file permissions (chmod) and ownership (chown) may appear correct. However, the root cause in many such cases is related to Access Control Lists (ACL), which can override traditional permission settings.

If the issue is related to connectivity rather than permissions, you may encounter SFTP problems like SFTP connection refused error.

What is FTP Permission Denied Error?

The FTP “open for write: permission denied” error occurs when a user tries to modify or overwrite an existing file but lacks effective write permissions on the server.

Even when directory and file permissions seem correct, hidden permission layers like ACL can block write access—this is one of the most common FTP errors in Linux environments affecting file operations.

Problem Overview

In this case:

• The FTP user (developer) had access to the directory
• Directory permissions were set correctly (755 or 775)
• File permissions also looked normal

However, checking ACL revealed:

#getfacl controllers/

Output:

user:developer:rwx              #effective:r-x
mask::r-x

Even though the user had rwx, the effective permission was reduced to r-x due to the ACL mask.

This prevented the user from writing or overwriting files.

Why This Happens (Root Cause)

ACL introduces an additional permission layer, and in some environments, security mechanisms like SELinux configuration in Linux can further restrict file access beyond standard permissions:

• The mask defines the maximum allowed permissions
• If the mask is restrictive (e.g., r-x), it overrides user permissions

So even if:

user:developer:rwx

It becomes:

effective:r-x

No write access → FTP overwrite fails

How to Fix FTP Permission Denied Error (Step-by-Step)

Step 1: Check ACL Permissions

#getfacl /var/www/your-project-path

Look for:

mask::r-x
#effective:r-x

Step 2: Fix the ACL Mask

Update the mask to allow write access:

#setfacl -m mask:rwx /var/www/your-project-path

Step 3: Apply Permissions Recursively (if needed)

#setfacl -R -m u:developer:rwx /var/www/your-project-path
#setfacl -R -m mask:rwx /var/www/your-project-path

Step 4: (Optional) Remove ACL Completely

If ACL is not required in your setup, it’s better to remove it:

#setfacl -bR /var/www/your-project-path

This restores standard Linux permission behavior and removes the + sign from ls -l.

Important: ACL can silently block write access even when traditional permissions look correct.

Real-World Insight

In many production environments, this issue commonly appears when:

• Multiple users or deployment tools modify permissions
• Default ACLs are applied automatically on directories
• CI/CD pipelines override permission settings

Ignoring ACL can lead to repeated FTP failures even after fixing chmod/chown.

Key Takeaways

• FTP overwrite errors are often caused by ACL mask restrictions
• Standard permissions (chmod/chown) may not reflect actual access
• Always check ACL using getfacl
• Fix using setfacl -m mask:rwx or remove ACL entirely
• Understanding ACL ensures stable and predictable server behavior

Conclusion

FTP upload issues—especially when only overwriting fails—are often caused by hidden ACL restrictions rather than basic permission misconfigurations.

By identifying and correcting the ACL mask, or removing ACL entirely, you can restore proper file write access and ensure smooth FTP operations.

Understanding how ACL interacts with standard permissions is essential for maintaining stable and predictable server behavior in Linux environments.

If you’re facing persistent server permission issues or need expert assistance with Linux server management, consider professional support to ensure secure and error-free operations.

The post How to Fix FTP Permission Denied in Linux (ACL) appeared first on Server Management Services | Cloud Management | Skynats.