Index

Topics

The knowledge base is organized by operational domain, with product and technology tags kept secondary.

Domains

Mail & Services

Diagnosing deferred Mailcow delivery: local firewall or remote MX refusal?

A short evidence-driven workflow for distinguishing local SMTP connectivity problems from selective refusal by a remote mail server.

Monitoring & Security

Monitoring Proxmox VE with Prometheus using API tokens and a trusted CA

A production-oriented pattern for collecting Proxmox metrics without disabling TLS verification or using a full administrator account.

Storage & Backup

Migrating Ceph authentication keys to aes256k without losing cluster access

A staged operational approach to rotating Ceph service and client keys while preserving quorum and administrative access.

Technology tags

apiauthenticationcephmailcowmonitoringnetworkingpostfixprometheusproxmoxsecuritysmtpstoragetlstroubleshooting