Technical notes on email (SPF, DKIM, DMARC), DNS, Microsoft 365 / Google Workspace migrations and the workstation.https://grichard.eu/en-GBhttps://grichard.eu/en/blog/ai-at-work-it-technician-assistants-comparison/https://grichard.eu/en/blog/ai-at-work-it-technician-assistants-comparison/How I pick an AI assistant for scripts, troubleshooting and documentation: ChatGPT, Claude, Gemini, Copilot, Mistral, DeepSeek and Perplexity compared.Fri, 06 Nov 2026 00:00:00 GMTAIChatGPTClaudeGeminiGDPRhttps://grichard.eu/en/blog/chatgpt-it-use-cases-pricing-privacy/https://grichard.eu/en/blog/chatgpt-it-use-cases-pricing-privacy/ChatGPT in an IT job: scripts, troubleshooting, documentation, what not to paste into it, and the Free, Go, Plus, Pro and Business plans.Fri, 06 Nov 2026 00:00:00 GMTChatGPTOpenAIAIGDPRhttps://grichard.eu/en/blog/claude-it-use-cases-pricing-privacy/https://grichard.eu/en/blog/claude-it-use-cases-pricing-privacy/Claude in an IT job: scripts, long documents, troubleshooting, privacy, and the Free, Pro, Max, Team and Enterprise plans as of 6 November 2026.Fri, 06 Nov 2026 00:00:00 GMTClaudeAnthropicAIGDPRhttps://grichard.eu/en/blog/credit-mutuel-arkea-cyberattack-november-2026/https://grichard.eu/en/blog/credit-mutuel-arkea-cyberattack-november-2026/Crédit Mutuel Arkéa lost around €100M in a cyberattack through a supplier: confirmed facts, open questions, and what customers and businesses should do.Fri, 06 Nov 2026 00:00:00 GMTCrédit Mutuel ArkéaCyberattackPhishingBankinghttps://grichard.eu/en/blog/deepseek-it-use-cases-privacy/https://grichard.eu/en/blog/deepseek-it-use-cases-privacy/DeepSeek in an IT job: its appeal through the API, European regulators’ concerns about data, and why I hand it no data.Fri, 06 Nov 2026 00:00:00 GMTDeepSeekAIGDPRPrivacyhttps://grichard.eu/en/blog/gemini-it-use-cases-pricing-privacy/https://grichard.eu/en/blog/gemini-it-use-cases-pricing-privacy/Gemini in an IT job: Google Workspace, scripts, documents, GDPR, and the Google AI Plus, Pro and Ultra plans in euros as of 6 November 2026.Fri, 06 Nov 2026 00:00:00 GMTGeminiGoogleAIGDPRhttps://grichard.eu/en/blog/microsoft-copilot-365-it-use-cases-pricing-privacy/https://grichard.eu/en/blog/microsoft-copilot-365-it-use-cases-pricing-privacy/Microsoft Copilot at work: free Copilot Chat, Copilot Business, access rights, privacy, and per-user prices excluding VAT as of 6 November 2026.Fri, 06 Nov 2026 00:00:00 GMTCopilotMicrosoft 365AIGDPRhttps://grichard.eu/en/blog/mistral-le-chat-vibe-it-use-cases-pricing-privacy/https://grichard.eu/en/blog/mistral-le-chat-vibe-it-use-cases-pricing-privacy/Mistral AI, a French provider: Le Chat now called Vibe, its use for scripts and development, and the Free, Pro and Team plans as of 6 November 2026.Fri, 06 Nov 2026 00:00:00 GMTMistralLe ChatAIGDPRhttps://grichard.eu/en/blog/openssh-symfony-vulnerabilities-november-2026/https://grichard.eu/en/blog/openssh-symfony-vulnerabilities-november-2026/OpenSSH flaw (CVE-2026-123158) on Linux systems without PAM such as Alpine, and Symfony security fixes of 4 November: who is affected and what to update.Fri, 06 Nov 2026 00:00:00 GMTOpenSSHSymfonyLinuxPatcheshttps://grichard.eu/en/blog/perplexity-search-sources-it-use-cases/https://grichard.eu/en/blog/perplexity-search-sources-it-use-cases/Perplexity in an IT job: a search that cites its sources, how to check it, what not to paste into it, and its plans in dollars.Fri, 06 Nov 2026 00:00:00 GMTPerplexityAISearchGDPRhttps://grichard.eu/en/blog/ram-ssd-shortage-prices-ai-2026/https://grichard.eu/en/blog/ram-ssd-shortage-prices-ai-2026/RAM and SSD prices are rising in 2026 as AI demand (HBM, servers) soaks up memory. What Samsung says, the impact on PCs, and when to buy.Fri, 06 Nov 2026 00:00:00 GMTRAMSSDHardwareSamsungAIhttps://grichard.eu/en/blog/cidr-subnet-mask-explained/https://grichard.eu/en/blog/cidr-subnet-mask-explained/CIDR notation (/24, /27), dotted-decimal masks, usable addresses and subnetting, with checked calculations and a free subnet calculator.Wed, 28 Oct 2026 00:00:00 GMTNetworkingCIDRSubnet maskSubnetIPv4RFC 1918https://grichard.eu/en/blog/dns-records-explained-a-mx-cname-txt/https://grichard.eu/en/blog/dns-records-explained-a-mx-cname-txt/What the A, AAAA, CNAME, MX, TXT, NS, SOA, CAA, PTR and SRV DNS records do: examples, classic pitfalls and basic dig and nslookup commands.Wed, 28 Oct 2026 00:00:00 GMTDNSMXCNAMETXTdignslookuphttps://grichard.eu/en/blog/exchange-online-smtp-auth-basic-authentication-end-2026/https://grichard.eu/en/blog/exchange-online-smtp-auth-basic-authentication-end-2026/Exchange Online turns off password-based SMTP AUTH by default at the end of December 2026: find the scanners, printers and apps that depend on it, then migrate.Wed, 28 Oct 2026 00:00:00 GMTExchange OnlineMicrosoft 365SMTPOAuthhttps://grichard.eu/en/blog/orange-mobile-outage-21-october-2026/https://grichard.eu/en/blog/orange-mobile-outage-21-october-2026/Ten hours without Orange and Sosh mobile service: timeline, announced cause, and concrete measures so an operator outage does not stop a small business.Wed, 28 Oct 2026 00:00:00 GMTOrangeOutageBusiness continuityhttps://grichard.eu/en/blog/patch-tuesday-october-2026-small-business/https://grichard.eu/en/blog/patch-tuesday-october-2026-small-business/October 2026 Patch Tuesday: an exploited Windows Shell flaw, a record number of fixes, two known issues and the end of Windows 11 24H2. The priorities.Wed, 28 Oct 2026 00:00:00 GMTPatch TuesdayWindows 11SecurityUpdateshttps://grichard.eu/en/blog/php-critical-flaws-cve-2026-109618-109619-what-to-do/https://grichard.eu/en/blog/php-critical-flaws-cve-2026-109618-109619-what-to-do/Two critical remote code execution flaws in PHP, fixed on 21 October 2026. Affected versions, a verified timeline, workarounds and an action plan.Wed, 28 Oct 2026 00:00:00 GMTPHPVulnerabilityHostinghttps://grichard.eu/en/blog/read-email-headers-received-spf-dkim-dmarc/https://grichard.eu/en/blog/read-email-headers-received-spf-dkim-dmarc/Where to find headers in Outlook, Gmail and Thunderbird, how to read Received, Authentication-Results and DKIM-Signature, and spot spam or spoofing.Wed, 28 Oct 2026 00:00:00 GMTHeadersSPFDKIMDMARCDeliverabilityhttps://grichard.eu/en/blog/secure-boot-2011-certificates-expiry-check/https://grichard.eu/en/blog/secure-boot-2011-certificates-expiry-check/The 2011 Secure Boot certificates expired in June and October 2026: how to check a PC or server, update firmware, and handle Linux, dual-boot and VMs.Wed, 28 Oct 2026 00:00:00 GMTSecure BootUEFIWindowsLinuxVirtualizationhttps://grichard.eu/en/blog/supermarket-fridge-cyberattack-refrigeration-controllers/https://grichard.eu/en/blog/supermarket-fridge-cyberattack-refrigeration-controllers/11 to 12 October 2026: refrigeration controllers hacked in hundreds of French supermarkets. Equipment, cause, losses and measures for any connected device.Wed, 28 Oct 2026 00:00:00 GMTCyberattackIoTEnd of lifehttps://grichard.eu/en/blog/tls-certificate-lifetimes-200-100-47-days/https://grichard.eu/en/blog/tls-certificate-lifetimes-200-100-47-days/Since 15 March 2026 a public TLS certificate lasts 200 days at most, then 100 days in 2027 and 47 days in 2029. The schedule and how to prepare.Wed, 28 Oct 2026 00:00:00 GMTTLSCertificatesACMELet's EncryptCAADNShttps://grichard.eu/en/blog/uefi-pxe-flaw-edk2-cve-2026-97631/https://grichard.eu/en/blog/uefi-pxe-flaw-edk2-cve-2026-97631/A critical EDK II firmware flaw allows code execution before Secure Boot during a PXE boot. Who is affected, what is fixed and how to reduce the risk.Wed, 28 Oct 2026 00:00:00 GMTUEFIPXEVulnerabilityhttps://grichard.eu/en/blog/windows-event-log-ids-to-know/https://grichard.eu/en/blog/windows-event-log-ids-to-know/The Windows event IDs to watch in a small business: logons (4624, 4625), accounts, groups, lockouts, Kerberos, with PowerShell filters.Wed, 28 Oct 2026 00:00:00 GMTWindowsLogsActive DirectoryAuditPowerShellhttps://grichard.eu/en/blog/windows-server-2016-end-of-support-january-2027/https://grichard.eu/en/blog/windows-server-2016-end-of-support-january-2027/Windows Server 2016 support ends on 12 January 2027: inventory, migrating to Server 2025 or 2022, ESU through Azure Arc, and Active Directory.Wed, 28 Oct 2026 00:00:00 GMTWindows ServerActive DirectoryMigrationESUhttps://grichard.eu/en/blog/dns-troubleshooting-dig-nslookup-propagation-ttl/https://grichard.eu/en/blog/dns-troubleshooting-dig-nslookup-propagation-ttl/Query the right server, understand DNS "propagation" and TTL, and spot the most common zone mistakes (apex CNAME, MX, TXT, delegation).Sat, 03 Oct 2026 00:00:00 GMTDNSdignslookupTTLhttps://grichard.eu/en/blog/email-deliverability-troubleshooting-spam-bounces/https://grichard.eu/en/blog/email-deliverability-troubleshooting-spam-bounces/Read a bounce message, analyze headers, check SPF/DKIM/DMARC, reputation and reverse DNS: a step-by-step approach to find the cause.Sat, 03 Oct 2026 00:00:00 GMTDeliverabilitySPFDKIMDMARChttps://grichard.eu/en/blog/email-migration-google-workspace-microsoft-365/https://grichard.eu/en/blog/email-migration-google-workspace-microsoft-365/Inventory, migration method, TTL, MX cutover and checks: the steps that prevent lost emails when you change mail providers.Sat, 03 Oct 2026 00:00:00 GMTMicrosoft 365Google WorkspaceIMAPhttps://grichard.eu/en/blog/secure-microsoft-365-google-workspace-baseline-settings/https://grichard.eu/en/blog/secure-microsoft-365-google-workspace-baseline-settings/MFA, admin accounts, legacy authentication, auto-forwarding, external sharing, backup and offboarding: the essential measures for a small business.Sat, 03 Oct 2026 00:00:00 GMTMicrosoft 365Google WorkspaceSecurityhttps://grichard.eu/en/blog/spf-dkim-dmarc-explained/https://grichard.eu/en/blog/spf-dkim-dmarc-explained/What each DNS record does, ready-to-adapt examples, common pitfalls and a step-by-step rollout plan up to a DMARC reject policy.Sat, 03 Oct 2026 00:00:00 GMTSPFDKIMDMARCDNShttps://grichard.eu/en/blog/windows-10-end-of-support-upgrade-to-windows-11/https://grichard.eu/en/blog/windows-10-end-of-support-upgrade-to-windows-11/Hardware requirements, fleet inventory, Extended Security Updates (ESU), Windows 11 lifecycle and a migration plan for a small business.Sat, 03 Oct 2026 00:00:00 GMTWindows 11Windows 10