Talk to enough SaaS infrastructure teams and the same story comes up: nobody planned for running out of IP addresses. Engineering is busy shipping product, the cloud footprint doubles every year or so, and then one day someone realizes the /24 that seemed generous in year one (256 addresses, after all) is nearly spent. Delayed launches, ballooning NAT costs, panic-buying at premium prices. All of it avoidable with a bit of foresight.
Why SaaS Companies Run Out of IPv4 Addresses
SaaS growth is unpredictable by nature. A successful product launch, a large enterprise onboarding, a new regional deployment — any of these can spike address consumption overnight. And several forces tend to pile up at once:
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- Multi-cloud expansion: Every cloud region and VPC eats routable space, and providers now charge for public IPv4 usage (AWS introduced fees on public IPv4 addresses in 2024).
- Dedicated IP requirements: Enterprise customers increasingly want dedicated IPs for email sending, compliance isolation, and per-tenant rate limiting.
- Email deliverability: Scaling outbound mail means managing IP reputation — which means dedicated, warmed-up addresses.
- Direct interconnection: Peering, VPN concentrators, load balancers. All of them need public-facing space.
Forecasting Your IPv4 Requirements
Good planning starts with an honest demand model. Work backward from your infrastructure roadmap, not from what you’re using today. Those are different numbers, and the gap is where teams get burned.
Build a 24-Month Demand Model
Inventory every current consumer of public address space, then project growth for each category. Something like this:
| Address Consumer | Current Usage | Growth Driver | 24-Month Projection |
|---|---|---|---|
| Load balancers / ingress | 32 IPs | 2x traffic growth | 64 IPs |
| Dedicated tenant IPs | 64 IPs | Enterprise tier expansion | 256 IPs (/24) |
| Email sending pools | 16 IPs | Marketing volume | 48 IPs |
| Cloud region expansion | 128 IPs | 2 new regions | 384 IPs |
| Reserve / headroom | — | 25% buffer | 190 IPs |
Plan in Prefix Sizes, Not Single Addresses
Nobody trades single addresses. Space moves in CIDR blocks — /24 (256 addresses), /23 (512), /22 (1,024) and up. Plan your acquisition in those units, and model with a 20–30% buffer. The pattern is consistent: teams that underestimate consumption end up fragmenting their space and complicating routing.
Acquiring IPv4 Space: Lease vs. Buy
The free pools at ARIN, RIPE, and the other RIRs ran dry long ago. That leaves growing companies three realistic paths: transfer purchases, leasing, or renegotiating with cloud providers. For most SaaS operators, the choice comes down to capital and time horizon.
Buying via Transfer
Purchasing blocks through the transfer market gets you a permanent asset. Prices have hovered in the $30–$50 per address range in recent years, so a /24 typically runs $8,000–$13,000. Transfers require RIR approval and clean documentation — working with a marketplace that verifies seller legitimacy and handles escrow cuts the risk substantially. IP4 Market, for example, specializes in verified transfers with transparent pricing, which makes it a sensible option for companies buying their first blocks.
Leasing
Leasing fits companies with uncertain demand or tight capital. Rates typically run $0.30–$0.60 per address per month — roughly $75–$150/month for a /24. Ideal for short-term projects, regional pilots, or bridging demand until a purchase is budgeted. IP4 Market also offers lease options with vetted block owners, so you’re not gambling on unverifiable listings.
Which Is Right for You?
| Factor | Buy (Transfer) | Lease |
|---|---|---|
| Upfront cost | High ($8k–$13k per /24) | Low (monthly) |
| Long-term value | Appreciating asset | Operating expense |
| Best for | Steady, permanent growth | Uncertain or temporary demand |
| Time to acquire | 4–8 weeks (RIR approval) | Days |
Best Practices for Managing Your Address Space
Acquisition is only half the equation. The other half is disciplined lifecycle management:
- Deploy a real IPAM solution: Spreadsheets fail at scale. Use a dedicated IPAM tool (NetBox, phpIPAM, or a commercial platform) as the single source of truth.
- Track utilization monthly: When any block crosses 80% utilization, trigger a new acquisition review. Don’t wait.
- Maintain RPKI and IRR hygiene: Keep route origin authorizations and IRR objects current — stale records cause routing problems and complicate future transfers.
- Audit for unused space: Companies routinely recover 10–20% of their holdings by reclaiming stale allocations from decommissioned environments. Unused blocks can even be leased out for passive income.
- Document transfer eligibility: Make sure your RIR account details, point of contact, and legal entity records are accurate before you need them urgently — not during an emergency.
Frequently Asked Questions
How many IPv4 addresses does a growing SaaS company actually need?
Most scaling SaaS companies find a /24 is the practical starting point for dedicated use cases, with a /22 or /23 as a comfortable medium-term target. Base the number on a documented 24-month demand model, not current usage.
Is it better to lease or buy IPv4 addresses?
Buy if demand is permanent and predictable — the blocks are appreciating assets. Lease if demand is uncertain, temporary, or you need space faster than a transfer can complete. Plenty of companies mix both: owned blocks for core infrastructure, leases for experiments.
How long does an IPv4 transfer take?
Typically 4–8 weeks including RIR review, though an experienced marketplace like IP4 Market streamlines documentation, escrow, and validation to keep delays to a minimum.
Will IPv6 eliminate the need for IPv4 planning?
Not for years. IPv6 adoption keeps growing, but enterprise customers, email ecosystems, and legacy integrations still require reliable IPv4 connectivity. Dual-stack operations mean your IPv4 needs remain critical.
Fast growth and address scarcity don’t have to collide. Forecast demand honestly, acquire space before you desperately need it, and manage your holdings with discipline — your infrastructure can then scale without IP bottlenecks. When you’re ready to expand your holdings, IP4 Market offers a trusted platform for buying, selling, and leasing IPv4 addresses, with verified sellers, secure escrow, and competitive pricing backed by deep market expertise.
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