Updated: 28 September 2026 · Applies to: Self-managed dedicated servers
How many IP addresses do you need? Too few and you must reorganise later; too many and you pay for addresses you never use. This guide gives you a simple way to count, and shows which block (/29, /28, /27, /26, /25 or /24) fits.
1. List what needs its own address
Write down every service and decide whether it needs a separate public address:
- The server itself (SSH, monitoring): 1 address.
- Websites and applications: usually share one address. Give an application its own address if a partner must allow-list it, if it needs separate firewall rules, or if you host it for a customer (How to run several websites on separate IP addresses with Nginx?).
- Virtual machines and containers with public addresses: 1 per machine.
- Outgoing services with their own reputation, such as mail servers for different domains or customers: 1 address per sending identity (How to give each domain or customer its own sending IP address in Postfix?).
- Test or staging environments that must be reachable from outside.
2. Add a reserve
Add about 25 percent for growth, and remember that the gateway, network and broadcast addresses are not usable. The usable counts are: /29 = 5, /28 = 13, /27 = 29, /26 = 61, /25 = 125, /24 = 253 (How many IP addresses come with a dedicated server and what do additional subnets cost?).
3. Choose the block
- 1 address: the single IP that most plans include.
- 2 to 5 addresses: an additional /29 (5 usable), or a plan that already includes 5.
- 6 to 13: an additional /28.
- 14 to 29: a /27. 30 to 61: a /26. 62 to 125: a /25. 126 to 253: a /24.
Keeping everything in one larger block is usually simpler than several small ones.
4. A note on mail and reputation
More addresses do not automatically mean more mail that reaches the inbox. Every address builds its own reputation from the mail that goes out through it. A few addresses with steady, regular volume and clean lists do better than many addresses with tiny volume each. Plan the number of sending addresses from the number of separate sending identities (brands, customers, or types of mail such as transactional and newsletters), not from the total volume. Then follow the warm-up steps in How to warm up a new sending IP address step by step?. Ucartz's Acceptable Use Policy allows several addresses and automation to manage mail, but does not allow using addresses to evade blocks or to spread a campaign thinly over many addresses (snowshoe sending).
5. An example
A small agency hosts 12 client websites, 3 customer virtual machines, a staging site and a company mail server for its own domain:
- Server: 1
- Websites: 1 shared (they use SNI)
- Customer virtual machines: 3
- Staging: 1
- Mail server for the agency domain: 1
- Total 7, plus 25 percent reserve, about 9 addresses. A single IP or one /29 (5 usable) is not enough; a /28 (13 usable) fits.
6. Order and configure
See How to order an additional IPv4 subnet for your dedicated server? to order, then How to add additional IPv4 addresses on Ubuntu with netplan? or How to add additional IPv4 addresses on AlmaLinux or Rocky Linux with nmcli? to configure the addresses.
Frequently asked questions
Can I start small and add a block later?
Yes. Additional subnets can be requested at any time.
Is IPv6 an alternative?
IPv6 gives you plenty of addresses, but many mail providers and partners still expect IPv4 for sending and allow-listing, so plan your IPv4 needs separately.
Need a dedicated server, more IP addresses, or a hand with the setup?
- Unmanaged dedicated servers: full root access and IPv4 subnets from /29 up to /24, ordered with the server or added later.
- Managed dedicated servers: our team looks after the operating system, updates, security and monitoring.
- Dedicated server locations: choose the country and data centre when you order.
Prefer a hand with the setup? Our engineers can do it for you: Hire an Expert, or use our on-demand server management.
