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DNS, mail & TLS certificates in practice
When a website or e-mail stops working, the cause is surprisingly often DNS, mail authentication or certificates. These articles show how to check, which commands to use and the typical mistakes.
A school report card for your website: security headers, e-mail protection and certificate, graded like at school
Type a domain and get a report card: grades for security headers, SPF/DMARC and the TLS certificate, an overall grade and teacher remarks. Free.
Can these domains be spoofed? We checked SPF and DMARC of 102 well-known domains, and only half of the banks reject forged mail
SPF, DMARC and MTA-STS of 102 well-known domains: 59 reject forged mail, 21 only monitor with p=none, 6 have no DMARC. Banks, Germany and Italy compared.
Three critical NGINX flaws: less dramatic than PHP2Shell, but patch them quickly anyway
NGINX fix in 1.30.6 and 1.31.7 (Plus 37.1.0.1, 37.0.5.1): which configurations are affected, how to check them and how to update containers.
Mitigating PHP2Shell when no update exists yet: php.ini settings for NAS, Plesk and your own servers
No PHP update yet on Synology? Three php.ini settings shrink the PHP2Shell attack surface — step by step for Web Station, Plesk and your own servers.
PHP emergency patch (PHP2Shell): how to check and patch your servers
Two critical PHP flaws, fixed in 8.5.12, 8.4.27, 8.3.36 and 8.2.35: what to do on Plesk, Synology, shared hosting, Docker and your own servers.
DNS migration without downtime: TTL, order of steps and a checklist for domain and hosting moves
Switch hosting or DNS provider without losing website or e-mail: lower the TTL, export the zone instead of retyping it, test before the cutover.
Mail landing in spam: SPF, DKIM and DMARC alignment explained
SPF, DKIM and DMARC explained simply: what each checks, why mail lands in spam although SPF passes, how to read headers — with a table and checklist.
Topics: Nextcloud Linux troubleshooting AI, LLMs & RAG Security & patches