Cloud Server for Email
cloudserverforemail.com · infrastructure@cloudserverforemail.com · +372 602 3545
EU-Based Infrastructure
Operating Since 2015
Operating Since 2015
Transactional vs. Marketing Email Separation Guide
Infrastructure Isolation for Reliable Transactional Delivery
Version 2026-04 · Cloud Server for Email
Critical principle: A marketing campaign that generates elevated complaints can degrade IP reputation and delay password reset emails. Never mix transactional and marketing traffic on the same IPs.
What Belongs in Each Pool
Transactional Pool (Dedicated IPs)
- Password reset emails
- Two-factor authentication (OTP)
- Order confirmations
- Account notifications
- Shipping notifications
- Payment receipts
- Security alerts
Marketing Pool (Separate IPs)
- Newsletters
- Promotional campaigns
- Product announcements
- Re-engagement campaigns
- Upsell/cross-sell emails
- Win-back campaigns
Domain Separation
| Pool | From Domain | Return-Path Domain |
|---|---|---|
| Transactional | noreply@yourdomain.com or transact.yourdomain.com | bounce.transact.yourdomain.com |
| Marketing | hello@mail.yourdomain.com | bounce.mail.yourdomain.com |
Using separate subdomains for return-path keeps domain reputation separate between pools and makes DMARC alignment straightforward for each traffic type.
PowerMTA Configuration
# Two separate virtual MTA pools
<virtual-mta-pool transactional-pool>
virtual-mta ip-203-0-113-1
virtual-mta ip-203-0-113-2
</virtual-mta-pool>
<virtual-mta-pool marketing-pool>
virtual-mta ip-203-0-113-3
virtual-mta ip-203-0-113-4
virtual-mta ip-203-0-113-5
</virtual-mta-pool>
# Route transactional by header or source port
<source 127.0.0.1:587>
virtual-mta-pool transactional-pool
</source>
<source 127.0.0.1:2587>
virtual-mta-pool marketing-pool
</source>
Monitoring Transactional Pool Separately
- Separate deferral rate query for transactional IPs in accounting log
- Alert threshold: any transactional deferral rate above 2% triggers immediate investigation
- Latency monitoring: P1 messages (OTP/password reset) should deliver within 60 seconds
- Separate Postmaster Tools IP reputation view for transactional IPs
- SNDS status for transactional IPs checked separately from marketing IPs
MailWizz Delivery Server Configuration
In MailWizz, configure two delivery servers — one pointing to the transactional injection port (587) and one to the marketing injection port (2587). Assign the correct delivery server in each campaign or use MailWizz's delivery server groups to automatically route transactional autoresponders to the transactional delivery server.
Even with perfect infrastructure separation, transactional deliverability ultimately depends on your list quality and engagement history across all traffic types. ISPs evaluate your domain reputation holistically — sustained poor performance on marketing traffic will eventually affect domain reputation and thus transactional delivery.