External DNS/SPF/DKIM/DMARC/MTA-STS/TLS/DNSBL diagnostics adapted from
arova-ai/agent-skills' email-server-diagnostics, combined with this
session's own direct mailcow migration experience (geeky/posta/postman
-> spoof consolidation): real container naming pattern
(mailcowdockerized-<service>-mailcow-1), mailcow's own official
helper-scripts/backup_and_restore.sh and update.sh, the acme-mailcow
cert container, and an explicit multi-tenant blast-radius guardrail
since one instance serves many unrelated businesses' domains.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
MalinandClaude Sonnet 5
3b8ef056cb