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Dedicated IP Strategy for Postchi

Executive Summary​

YES, you should absolutely dedicate an IP for the Postchi brand (system emails) and keep it separate from customer IPs.

Why Dedicated Brand IP?​

1. Reputation Protection​

  • Customer mistakes won't affect your system emails
  • If a customer sends spam, it won't damage Postchi's ability to send password resets
  • System emails maintain high deliverability regardless of customer behavior

2. Deliverability Reliability​

  • Gmail, Outlook, Yahoo track sender reputation by IP
  • Critical system emails (password resets, verifications) need 99.9%+ deliverability
  • One bad customer can tank IP reputation for weeks

3. Brand Trust​

  • Emails from @postchi.io should always land in inbox
  • Consistent IP = consistent reputation = inbox placement
  • Professional image: "We take email seriously"

4. Regulatory Compliance​

  • System emails are transactional (CAN-SPAM exempt)
  • Customer emails may be marketing (subject to CAN-SPAM)
  • Separate IPs = clear audit trail

5. Monitoring & Troubleshooting​

  • Easy to identify if system IP has issues
  • Can monitor customer IPs independently
  • Faster incident response

Tier 1: Postchi Brand IP (1 dedicated IP)​

Purpose: System/transactional emails only

  • Password resets
  • Email verification
  • Account notifications
  • Billing emails
  • Security alerts

Characteristics:

  • Very low volume (predictable)
  • 100% legitimate traffic
  • Strict sending policies
  • Monitor 24/7

Tier 2: Customer Shared IP Pool (Start with 2-3 IPs)​

Purpose: Customer email sending

  • Marketing campaigns
  • Transactional customer emails
  • Newsletters
  • Notifications

Characteristics:

  • Higher volume
  • Variable quality
  • Requires reputation management
  • Scale as customer base grows

Tier 3: High-Volume Customer Dedicated IPs (Future)​

Purpose: Enterprise customers with high volume

  • Customers sending 100K+ emails/month
  • White-label customers
  • Customers who want dedicated IP

IP Warming Schedule​

Brand IP (postchi.io)​

Since this is low-volume system emails, warming is simpler:

Week 1: 50 emails/day Week 2: 100 emails/day Week 3: 200 emails/day Week 4+: Full volume (likely still low)

Tip: You can accelerate by having team members trigger password resets, sign-ups, etc.

Customer Shared Pool IPs​

More aggressive warming needed:

Week 1: 200 emails/day per IP Week 2: 500 emails/day per IP Week 3: 1,000 emails/day per IP Week 4: 2,500 emails/day per IP Week 5: 5,000 emails/day per IP Week 6: 10,000 emails/day per IP Week 7+: Full volume

IP Allocation Architecture​

┌─────────────────────────────────────────────┐
│           Postchi Email Infrastructure       │
├─────────────────────────────────────────────┤
│                                             │
│  Brand IP: 203.0.113.10                    │
│  ├─ noreply@postchi.io                     │
│  ├─ security@postchi.io                    │
│  └─ support@postchi.io                     │
│                                             │
│  Customer Pool IPs:                         │
│  ├─ IP 1: 203.0.113.20 (Customers A-M)     │
│  ├─ IP 2: 203.0.113.21 (Customers N-Z)     │
│  └─ IP 3: 203.0.113.22 (Overflow/Testing)  │
│                                             │
│  Enterprise Dedicated IPs:                  │
│  ├─ IP X: Customer ABC Corp                │
│  └─ IP Y: Customer XYZ Inc                 │
│                                             │
└─────────────────────────────────────────────┘

DNS Configuration​

For Brand IP (203.0.113.10)​

# SPF Record
postchi.io.  IN  TXT  "v=spf1 ip4:203.0.113.10 -all"

# DKIM Record (use the generated key from script)
default._domainkey.postchi.io.  IN  TXT  "v=DKIM1; k=rsa; p=YOUR_PUBLIC_KEY"

# DMARC Record
_dmarc.postchi.io.  IN  TXT  "v=DMARC1; p=quarantine; rua=mailto:dmarc@postchi.io; ruf=mailto:dmarc@postchi.io; pct=100; adkim=s; aspf=s"

# MX Records (for bounce handling)
postchi.io.  IN  MX  10  s1.mx.postchi.io.
postchi.io.  IN  MX  20  s2.mx.postchi.io.

# A Record (if needed)
postchi.io.  IN  A  203.0.113.10

Note: For brand IP, use strict DKIM/SPF alignment (adkim=s; aspf=s) instead of relaxed.

For Customer IPs​

Customer domains will have their own DNS records with their assigned pool IP.

Monitoring Strategy​

Brand IP Monitoring (Critical)​

  • Uptime: 99.99% SLA
  • Deliverability: Alert if <99% inbox rate
  • Reputation: Daily checks on:
    • Google Postmaster Tools
    • Microsoft SNDS
    • Spamhaus
    • Barracuda
  • Bounce Rate: Alert if >2%
  • Complaint Rate: Alert if >0.1%

Customer IP Monitoring​

  • Uptime: 99.9% SLA
  • Deliverability: Alert if <95% inbox rate
  • Reputation: Weekly checks
  • Bounce Rate: Alert if >5%
  • Complaint Rate: Alert if >0.5%
  • Automatic quarantine: If customer IP gets blacklisted

Cost Considerations​

IP Costs (AWS/Digital Ocean example)​

  • Dedicated IP: $3-5/month
  • Elastic IP: Free if attached, $3.60/month if idle

Brand IP (1): ~$5/month​

Worth it? Absolutely. This protects your business.

Customer Pool (3): ~$15/month​

Worth it? Yes. Room to grow and isolate problems.

Total: ~$20/month​

ROI: Priceless for reputation protection

Implementation Checklist​

  • Provision dedicated IP for postchi.io brand
  • Configure reverse DNS (PTR record) for brand IP
  • Set up DKIM keys for postchi.io (use generated keys)
  • Configure SPF with strict IP (only brand IP)
  • Set up DMARC with quarantine policy
  • Add MX records for bounce handling
  • Start IP warming (50 emails/day)
  • Set up monitoring (Google Postmaster, etc.)
  • Configure separate SMTP connection pool for brand IP
  • Update password-reset service to use brand domain/IP ✅
  • Provision 2-3 IPs for customer pool
  • Implement customer IP assignment logic
  • Set up customer IP warming schedule
  • Create IP reputation dashboard

Best Practices​

Do's:​

✅ Use dedicated brand IP only for system emails ✅ Monitor brand IP reputation daily ✅ Keep volume consistent (avoid spikes) ✅ Warm up IPs properly ✅ Set up feedback loops with ISPs ✅ Monitor bounce/complaint rates

Don'ts:​

❌ Don't mix customer emails with brand IP ❌ Don't share brand IP across environments (dev/prod) ❌ Don't skip IP warming ❌ Don't ignore blacklist alerts ❌ Don't use shared IPs for high-value customers

Conclusion​

Dedicating an IP for the Postchi brand is not just recommended—it's essential for a professional email service platform. The cost is minimal (~$5/month) compared to the risk of losing the ability to send critical system emails.

Next Steps:

  1. Provision brand IP
  2. Configure DNS records (use generated DKIM keys)
  3. Start IP warming with test emails
  4. Begin production use after 2-week warm-up