Migrating to MegaBrutal’s SMTP Server: Step-by-Step Checklist
1. Pre-migration assessment
- Inventory: List all applications, services, and devices that send mail (apps, CRON jobs, printers, monitoring alerts).
- Volume: Measure daily/hourly message volume and peak concurrency.
- Dependencies: Note authentication methods, relay requirements, TLS usage, DKIM/SPF/DMARC, and rate limits.
- Backup: Export existing SMTP configs and mail queues; snapshot mail server and key configurations.
2. Plan DNS and authentication
- SPF: Add/modify TXT record to include MegaBrutal’s sending IPs (example: “v=spf1 mx include:megabrutal.example ~all”).
- DKIM: Generate MegaBrutal DKIM keys, publish public key in DNS as TXT, and configure selector in server.
- DMARC: Create or update DMARC record to align policy with migration (“v=DMARC1; p=quarantine; rua=mailto:postmaster@yourdomain”).
- Reverse DNS: Ensure MegaBrutal IPs have rDNS matching your mail domain.
3. Security and encryption
- TLS: Require STARTTLS or TLS v1.2+ for inbound/outbound where supported.
- Auth: Use strong credentials and OAuth or client certificates if supported.
- Access control: Restrict which hosts can relay through MegaBrutal via IP allowlists or authentication.
- Firewall: Open necessary SMTP ports (25 for MTA, 587 for submission, 465 if using SMTPS) only to trusted sources.
4. Configuration and integration
- Credentials: Create service accounts or API keys for each sending service.
- Server settings: Update MTA settings (relayhost, port, auth method, TLS options) on each source.
- Rate limits and throttling: Configure per-service limits to avoid being rate-limited by MegaBrutal.
- Headers and signatures: Ensure headers added by MegaBrutal (Received, Authentication-Results) meet your logging/audit needs.
5. Testing (staged rollout)
- Sandbox test: Start with a single low-risk application to send through MegaBrutal.
- Deliverability checks: Send to test inboxes (Gmail, Outlook, Yahoo) and verify SPF/DKIM/DMARC pass, no spam flagging.
- Bounce & error handling: Verify bounce messages and DSNs are properly returned and processed.
- Monitoring: Enable logging and alerts for delivery failures, auth errors, and latency.
6. Migration cutover
- Phased switch: Gradually update senders in batches (e.g., 10% → 50% → 100%) to limit impact.
- Traffic monitoring: Watch queues, delivery rates, and bounce volumes in real time during each phase.
- Fallback plan: Keep previous SMTP routes available and be ready to revert quickly if critical issues arise.
7. Post-migration tasks
- Full validation: Re-run deliverability tests and confirm SPF/DKIM/DMARC alignment across major providers.
- Cleanup: Remove old SMTP credentials, close unused ports, and delete obsolete DNS records if appropriate.
- Documentation: Update runbooks, SMTP configuration docs, and contact lists for MegaBrutal support.
- Retention & logging: Ensure logs are retained per policy and integrate with SIEM/monitoring.
8. Long-term maintenance
- Monitoring: Maintain dashboards for delivery rates, bounce rates, latencies, and auth failures.
- Security reviews: Rotate credentials and DKIM keys periodically; review access lists quarterly.
- Performance tuning: Adjust throttles and concurrency limits based on observed patterns.
- Compliance: Periodically verify SPF/DKIM/DMARC records and rDNS for any IP changes from MegaBrutal.
Follow this checklist to minimize downtime and deliverability problems when migrating to MegaBrutal’s SMTP server.
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