Infrastructure Architecture
IP Pool Sizing & Subnet Allocation Calculator
Calculate the ideal number of dedicated IPv4 addresses and CIDR subnets based on daily volume and ISP throttling limits.
Recommended Dedicated IPs
4 IPs
/30 Subnet Recommended
Hourly Throughput Required
37,500 / hr
Across active pool
Volume per IP per Day
37,500 msgs
Within safe ISP reputation bounds
Warmup Ramp Duration
21 – 28 Days
Safe reputation ramp
Subnet Architecture Recommendation
A dedicated /30 subnet (4 IPv4 addresses) provides optimal traffic distribution. Split 2 IPs for marketing newsletters and 2 IPs for high-priority transactional emails to isolate deliverability signals.
Provision Clean Dedicated IP Subnets Instantly
AutoSMTP provisions pre-checked /29 and /28 ARIN/RIPE subnets with rDNS configured.
Engineering Principles for High-Volume IP Pool Architecture
Under-provisioning your IP pool leads to severe rate-limiting and 421 4.7.0 temporary deferrals from Gmail and Outlook. Conversely, over-provisioning dilutes sending volume across too many IPs, preventing each individual IP from establishing consistent reputation history with major mailbox providers.
The Goldilocks Volume Rule
Maintain between 20,000 to 50,000 emails per IP per day. Senders transmitting under 5,000/day often suffer unpredictable spam filtering due to low statistical confidence.
Subnet Diversity & CIDR
Spam filters evaluate both individual
/32 IPs and parent /24 subnets. Distribute IPs across diverse network subnets to mitigate blocklist collateral damage.Automated Pool Warming
New IPs in the pool must be warmed incrementally. Use AutoSMTP virtual queues to automatically route overflow through seasoned IPs while the new subnet establishes trust.