IT Toolbox

Computer guides

Tutoriels pratiques

How to

Short, practical guides to complete an IT task without wasting time.

WordPress

How to activate WordPress debug logs

Save WordPress errors to a log file without showing them to visitors.

Intermediate • 5 min
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Microsoft 365 & Cloud

How to analyze a policy Conditional Access

This BAOI guide provides a structured method for analyzing an access policy without multiplying unnecessary changes.

Intermediate • 15-30 min
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WordPress

How to analyze a WordPress redirect loop

The redirect loops often come from a disagreement between WordPress, proxy, HTTPS and cache.

Intermediate • 20 min
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Microsoft 365 & Cloud

How to analyze an Auto-Divd problem

Auto SQL is often at the heart of Outlook or d profile creation problems, old Exchange environments.

Intermediate • 20 min
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Cybersecurity

How to analyze an Event ID 4625

L,Event ID 4625 contains several fields useful for finding the source of,failure of authentication.

Intermediate • 15 min
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Cybersecurity

How to analyze S Channel 36874 and 36888

This guide provides a structured method for analyzing s Channel 36874 and 36888.

Intermediate • 15-30 min
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Backup & PRA

How to analyze VSS 813 and 12289

This BAOI guide provides a structured method for analyzing vss 813 and 12289.

Intermediate • 15-30 min
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Guide

How to calculate downtime allowed by an SLA

Turn an availability percentage into understandable downtime and verify contractual exclusions.

Intermédiaire • 10–20 min
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Cybersecurity

How to check a 802.1X Wi-Fi configuration

A diagnosis 802.1X must follow the path supposing → point of access → RADIUS → identity/certificate.

Advanced • 25 min
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DNS & Email

How to check a DMARC record

Control the presence and policy of a field.

Intermediate • 5 min
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DNS & Email

How to check a DNS AXFR zone transfer

This BAOI guide provides a structured method for checking a zone transfer dns axfr without multiplying unnecessary changes.

Intermediate • 15-30 min
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Storage, NAS & SAN

How to check a LACP aggregate

This BAOI guide provides a structured method for checking a lacp aggregate without multiplying unnecessary changes.

Intermediate • 15-30 min
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DNS & Email

How to check a SPF record

Control the FPS published in the DNS of a mail domain.

Intermediate • 5 min
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Backup & PRA

How to check a synthetic full backup

A synthetic full primarily stresses the backup repository, so we must distinguish source, chain and target storage.

Advanced • 20 min
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Cybersecurity

How to check a TLS certificate with OpenSSL

OpenSSL allows you to quickly control TLS certificate, string and trading from a command line.

Intermediate • 15 min
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Windows Server & Active Directory

How to check Active Directory replication

Failure to perform Active Directory can cause inconsistent GPOs, different accounts depending on DCs or errors of authentication.

Advanced • 15 min
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Windows Server & Active Directory

How to check Active Directory Sites and Services

This BAOI guide provides a structured method for checking active sites and services, without multiplying unnecessary changes.

Intermediate • 15-30 min
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Guide

How to check an LDAPS certificate on Active Directory

Check the certificate presented by a domain controller, its trust chain, name, and expiration before troubleshooting LDAPS.

Intermédiaire • 10–20 min
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Windows Server & Active Directory

How to check if a PC is attached to a domain

Quickly determine whether a Windows computer is a member of an Active Directory domain….

Beginner • 2 min
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Cybersecurity

How to check if Windows firewall is enabled

Control the Windows firewall status on Domain, Private and Public profiles.

Beginner • 3 min
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Linux

How to check the disk space of, Linux server

Quickly display the use file systems on Linux.

Beginner • 3 min
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DNS & Email

How to check MX records of a domain

Identify servers that receive emails from a domain.

Beginner • 3 min
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Networking & Wi‑Fi

How to check ports listening on Windows

Identify locally listening ports/UDPs and associated processes.

Intermediate • 5 min
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Windows Server & Active Directory

How to check SMB Signing

This BAOI guide provides a structured method for checking smbsign without multiplying unnecessary changes.

Intermediate • 15-30 min
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DNS & Email

How to check SPF, DKIM and DMARC records together

The delivability depends on the actual behaviour of the sender and not only the presence of three DNS records.

Intermediate • 20 min
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Cybersecurity

How to check the of expiration of an HTTPS certificate

Check the validity period of the TLS certificate submitted by a site.

Intermediate • 5 min
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Windows Server & Active Directory

How to check the disk space of a Windows server

Quickly display the space used and available on volumes of a Windows server…

Beginner • 3 min
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Networking & Wi‑Fi

How to check the route used to a server

Observer the different network jumps borrowed by packages to a destination…

Beginner • 4 min
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FortiGate & VPN

How to check the state of an IPsec FortiGate tunnel

Quickly check the state of the IPsec tunnels since the FortiGate LTC….

Advanced • 8 min
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Cybersecurity

How to check the string of an HTTPS certificate with OpenSSL

s_client allows to see the certificate actually presented by a server and the intermediate certificates sent to the client.

Intermediate • 10 min
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Cybersecurity

How to check the, state of BitLocker

Check if Windows volumes are encrypted with BitLocker and know their status.

Intermediate • 3 min
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Backup & PRA

How to check VSSKyr backups

Control the Windows VSS Writers status when a backup using VSS fails….

Intermediate • 5 min
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Microsoft 365 & Cloud

How to clean an old Auto SQL Exchange

This BAOI guide provides a structured method for cleaning an old auto-Catch exchange without multiplying unnecessary changes.

Intermediate • 15-30 min
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DNS & Email

How to correct Sender mismatch with an authenticated SMTP

The name of the user is given in the form of the name of the user.

Intermediate • 10 min
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Windows Server & Active Directory

How to create an Active Directory user with PowerShell

Create a new AD user properly using the Active 1992ry module….

Intermediate • 8 min
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Guide

How to create and check a DNS CAA record

Restrict authorized certificate authorities without breaking automated renewals.

Intermédiaire • 10–20 min
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Guide

How to decode a JWT locally without exposing the token

Read a JWT header and payload for troubleshooting while remembering that decoding never validates the signature.

Intermédiaire • 10–20 min
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DNS & Email

How to deploy DMARC gradually without blocking legitimate emails

A DMARC policy must be gradually deployed to identify all legitimate sources before moving to the quarantine or the mundane.

Intermediate • 30 min
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FortiGate & VPN

How to diagnose a connected VPN without access to the LAN

The tunnel can be established while routing, policies or DNS still prevent access to resources.

Intermediate • 20 min
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Linux

How to diagnose a docker container that restarts

The first error of application is often masked by aggressive ROUND policy.

Intermediate • 15 min
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Windows Server & Active Directory

How to diagnose a gMSA

This BAOI guide provides a structured method for diagnosing a gmsa without multiplying unnecessary changes.

Intermediate • 15-30 min
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Linux

How to diagnose a Linux filesystem read-only

Reading-only editing can be a protective measure after a storage error or filesystem.

Advanced • 20 min
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FortiGate & VPN

How to diagnose a Phase 2 IPsec FortiGate

When Phase 1 is up but traffic does not pass, the selectors and Phase 2 parameters are the first items to compare.

Advanced • 25 min
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Networking & Wi‑Fi

How to diagnose a position in 169.254.x.x

This guide allows you to quickly identify why a Windows station does not get a DHCP lease.

Beginner • 10 min
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Virtualisation

How to diagnose a Proxmox cluster without quorum

This BAOI guide provides a structured method for diagnosing a proxmox cluster without quorum.

Intermediate • 15-30 min
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Linux

How to diagnose a systemd timer

This BAOI guide provides a structured method for diagnosing a systemd timer without multiplying unnecessary changes.

Intermediate • 15-30 min
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Storage, NAS & SAN

How to diagnose a WPA3 connection

This BAOI guide provides a structured method for diagnosing a wpa3 connection without multiplying unnecessary changes.

Intermediate • 15-30 min
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Virtualisation

How to diagnose an AVHDX Hyper-V

This BAOI guide provides a structured method for diagnosing a hyper-v avhdx chain.

Intermediate • 15-30 min
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Storage, NAS & SAN

How to diagnose an HTTP 504 error

A 504 must be broken down between the proxy network and backend processing time.

Intermediate • 20 min
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Microsoft 365 & Cloud

How to diagnose an Intune device that does not conform

This BAOI guide provides a structured method for diagnosing an intune device that is not compliant without multiplying unnecessary changes.

Intermediate • 15-30 min
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WordPress

How to diagnose cURL 28 in WordPress

This guide provides a structured method for diagnosing the 28 in wordpress.

Intermediate • 15-30 min
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Networking & Wi‑Fi

How to diagnose DHCP Snooping

This BAOI guide provides a structured method for diagnosing dhcp snooping without multiplying unnecessary changes.

Intermediate • 15-30 min
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Storage, NAS & SAN

How to diagnose DNSSEC and a SERVFAIL

This BAOI guide provides a structured method for diagnosing dnssec and a serfail without multiplying unnecessary changes.

Intermediate • 15-30 min
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Storage, NAS & SAN

How to diagnose Event ID 129 and 153

This guide provides a structured method for diagnostics ID 129 and 153.

Intermediate • 15-30 min
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Windows Server & Active Directory

How to diagnose FSRM and File Screening

This BAOI guide provides a structured method for diagnosing fsrm and file screen without multiplying unnecessary changes.

Intermediate • 15-30 min
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Storage, NAS & SAN

How to diagnose HTTP 429 and the limiting spleen

This guide provides a structured method for diagnosing http 429 and the limiting spleen without multiplying unnecessary changes.

Intermediate • 15-30 min
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Windows Server & Active Directory

How to diagnose inaccessible SMB sharing

An inaccessible SMB sharing can come from DNS, port 445, the sharing name or permissions. These layers must be tested in this order.

Intermediate • 10 min
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FortiGate & VPN

How to diagnose IPsec Phase 1 error on FortiGate

A Phase 1 error means that IPsec peers fail to properly establish the IKE before even negotiating the Phase 2 selectors.

Advanced • 20 min
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Bases de data & SQL

How to diagnose MySQL 1213 Paullock

This BAOI guide provides a structured method for diagnosing mysql 1213-2.

Intermediate • 15-30 min
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Microsoft 365 & Cloud

How to diagnose OneDrive stuck syncing

Start by identifying the specific file in error before any re-uploading of the client.

Beginner • 15 min
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Microsoft 365 & Cloud

How to diagnose Outlook blocked on Loading Profile

A short method allows to distinguish add-in, local profile and Microsoft 365 problem.

Beginner • 15 min
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Storage, NAS & SAN

How to diagnose SD-WAN rule

This BAOI guide provides a structured method for diagnosing a sd-wan rule without multiplying unnecessary changes.

Intermediate • 15-30 min
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Virtualisation

How to diagnose vMotion failure

This BAOI guide provides a structured method for diagnosing vmotion failure without multiplying unnecessary changes.

Intermediate • 15-30 min
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Virtualisation

How to diagnose VMware C BT

This BAOI guide provides a structured method for diagnosing vmware cbt without multiplying unnecessary changes.

Intermediate • 15-30 min
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Backup & PRA

How to diagnose VSS Writers before backup

Before modifying VSS, you must identify precisely which of the following year, and which service or application it belongs to, is not.

Intermediate • 10 min
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Windows & Poste client

How to diagnose Windows Update 0x800F0922

This BAOI guide provides a structured method for diagnosing Windows update 0x800f0922.

Intermediate • 15-30 min
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Backup & PRA

How to dimension an immutable backup

This BAOI guide provides a structured method for how to dimension an immutable backup without multiplying unnecessary changes.

Intermediate • 15-30 min
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WordPress

How to disable a WordPress plugin without access to wp-admin

Quickly disable an extension that causes a fatal error when the WordPress administration is not more accessible.

Intermediate • 5 min
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DNS & Email

How to empty and test DNS cache on Windows

When the DNS has just been modified or a post keeps an old answer, emptying the local cache and comparing resolutions allows quickly to isolate the problem.

Beginner • 5 min
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DNS & Email

How to empty DNS cache under Windows

Clear locally stored DNS entries when a site or server points to a wrong address….

Beginner • 2 min
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Networking & Wi‑Fi

How to find a STP loop on a network

This BAOI guide provides a structured method for finding a loop on a network without multiplying unnecessary changes.

Intermediate • 15-30 min
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Networking & Wi‑Fi

How to find the address Mac of a Windows computer

Identify the physical address of an Ethernet card or Wi-Fi….

Beginner • 2 min
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Windows Server & Active Directory

How to find the source of a Active Directory lock

This method allows you to trace the locked account back to the post, service or equipment using an old password.

Intermediate • 20 min
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Linux

How to find what fills a Linux drive

It is necessary to distinguish space saturation, saturation in inodes and deleted files still open before cleaning a Linux server.

Intermediate • 10 min
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Networking & Wi‑Fi

How to find your IP address on Windows

Quickly display the IPv4 address, gateway and DNS servers used by a Windows workstation…

Beginner • 2 min
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Windows Server & Active Directory

How to force GPO update

Force a Windows station to reapply user group and computer strategies….

Beginner • 3 min
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Guide

How to format and validate a JSON document

Validate JSON syntax, make it readable, and locate errors before an import or API call.

Intermédiaire • 10–20 min
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Windows Server & Active Directory

How to generate a Gp Report for a GPO in the year 2002

gp 2002 shows which GPOs are applied, refused or filtered for a position and user.

Beginner • 5 min
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Virtualisation

How to identify a VMware datastore that is filling

The growth of a data store must be attributed to VM,Producers, ISO or temporary files before cleaning.

Intermediate • 20 min
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Linux

How to identify what fills Docker

This BAOI guide provides a structured method for identifying what fills docker without multiplying unnecessary changes.

Intermediate • 15-30 min
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DNS & Email

How to identify your SMTP server

backover the SMTP server to use to send emails from an application.

Beginner • 5 min
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WordPress

How to Increase WordPress PHP Memory

Reasonably add the memory limit available for WordPress when, a memory error the requires.

Intermediate • 7 min
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DNS & Email

How to know the DNS servers used on Windows

Identify DNS solvers actually configured on a Windows desktop.

Beginner • 3 min
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Windows & Poste client

How to open Task Manager quickly

Quickly open Task Manager to scan CPU, memory, disk and applications.

Beginner • 1 min
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FortiGate & VPN

How to ping from a FortiGate

Test the reachability of a destination directly from the FortiGate….

Intermediate • 3 min
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WordPress

How to put WordPress in maintenance mode without plugin

Understand the.maintenance file used by WordPress during some updates.

Intermediate • 5 min
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Guide

How to read and verify Prometheus metrics

Verify that a target exposes consistent metrics and that Prometheus collects them successfully.

Intermédiaire • 10–20 min
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WordPress

How to recover WordPress after a plugin critical error

When wp-admin is inaccessible after the, activation or update of a plugin, the safest way is to disable only the suspicious plugin via the file system.

Intermediate • 15 min
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Networking & Wi‑Fi

How to renew an IP address DHCP under Windows

Force Windows to abandon and then re-demand an IP address to a DHCP server.

Beginner • 3 min
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Windows Server & Active Directory

How to Repair a Secure Active Directory Channel

This BAOI guide provides a structured method for repairing an activeway of security(16) without multiplying unnecessary changes.

Intermediate • 15-30 min
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Windows & Poste client

How to Repair Windows Update 0x80073712

This BAOI guide provides a structured method for repairing Windows update 0x80073712.

Intermediate • 15-30 min
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Windows & Poste client

How to repair Windows with DISM and SFC

Control and repair Windows components and then system files protected.

Intermediate • 15 à 45 min
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Windows Server & Active Directory

How to repair WinRM and PowerShell Remoting

This BAOI guide provides a structured method for how to repair winrm and powershell remoting without multiplying unnecessary changes.

Intermediate • 15-30 min
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Microsoft 365 & Cloud

How to resolve overly long OneDrive paths

This BAOI guide provides a structured method for solving the paths too long a Mount without multiplying unnecessary changes.

Intermediate • 15-30 min
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DNS & Email

How to restart DNS Client service on Windows

Relaunch DNS Client service when required by a specific troubleshooting.

Intermediate • 3 min
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Linux

How to scan a systemd service that does not start

systemctl gives the immediate state of the service while journalctl often explains why the main process has stopped.

Intermediate • 10 min
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Guide

How to size a switch PoE budget

Add maximum device power draw and retain suitable headroom for startup and expansion.

Intermédiaire • 10–20 min
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Guide

How to size usable RAID capacity

Compare raw capacity, usable capacity, fault tolerance, and smallest-disk impact before purchasing storage.

Intermédiaire • 10–20 min
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Microsoft 365 & Cloud

How to solve SMTP 550 5.7.60 Send As

This BAOI guide provides a structured method for solving smtp 550 5.7.60 sendl as.

Intermediate • 15-30 min
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Imprimantes & Scan

How to test a scan to SMB folder

The diagnosis must separate network, authentication and SMB compatibility.

Beginner • 15 min
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DNS & Email

How to test a SMTP server with OpenSSL

OpenSSL allows you to check the connection to the server, the borough and the certificate presented by a SMTP server before even testing the authentication.

Intermediate • 10 min
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Networking & Wi‑Fi

How to test a TCP port with PowerShell

Test-NetConnection allows you to quickly check if a station can reach a server on a specific TCP port, without installing any additional tool.

Beginner • 5 min
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Networking & Wi‑Fi

How to test a VLAN

A structured approach avoids looking for the way in when the VLAN does not already reach it.

Intermediate • 15 min
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Networking & Wi‑Fi

How to test a Windows port

Check if a service is responding to a specific port with Power Shell.

Beginner • 3 min
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DNS & Email

How to test DNS resolution of a domain

Check which DNS records are returned for a domain….

Beginner • 4 min
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Guide

How to test EAP-TLS authentication

Troubleshoot certificate-based 802.1X authentication by separating client, RADIUS, PKI, and network causes.

Intermédiaire • 10–20 min
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Cybersecurity

How to test if a site responds to HTTPS

Check that a web server responds to HTTPS and observe the returned HTTP code.

Beginner • 3 min
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Storage, NAS & SAN

How to test IPv6 without breaking IPv4

This BAOI guide provides a structured method for testing ipv6 without breaking ipv4 without multiplying unnecessary changes.

Intermediate • 15-30 min
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Storage, NAS & SAN

How to test RADIUS authentication

This BAOI guide provides a structured method for testing an authentication XXVI without multiplying unnecessary changes.

Intermediate • 15-30 min
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Guide

How to troubleshoot a Kubernetes Pod in CrashLoopBackOff

Identify why a container repeatedly starts and exits without hiding the cause with manual restarts.

Intermédiaire • 10–20 min
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Guide

How to troubleshoot AADSTS53003 in Microsoft Entra ID

Identify the exact Conditional Access policy blocking a sign-in without creating a broad exclusion.

Intermédiaire • 10–20 min
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Guide

How to troubleshoot SIP 488 Not Acceptable Here

Compare SDP offers, codecs, and media settings when a trunk or endpoint rejects a call.

Intermédiaire • 10–20 min
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Windows & Poste client

How to view installed software with PowerShell

Build an inventory of the software declared in Windows uninstall keys….

Intermediate • 5 min
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