If you've ever sat on a call with an ISP account manager trying to work out whether you need one static IP, five, or a whole block of them, you're not alone. It's one of those conversations that sounds technical enough to be intimidating, but the answer usually comes down to a handful of straightforward questions about what your business actually runs. Get it wrong one way and you can't host a VPN or a mail server properly. Get it wrong the other way and you're paying monthly for a dozen public IP addresses you'll never touch. This guide walks through what static and dynamic IPs really mean for a growing SME, and how to figure out the number you genuinely need.
Static vs dynamic: what's the real difference?
A dynamic IP is an address your ISP assigns to your connection that can change from time to time, usually when your router reconnects or the ISP reshuffles its pool. For most everyday browsing and cloud-based work, this is completely fine. Your laptop doesn't care what IP address your office is using today.
A static IP is fixed. It doesn't change, and that matters when something outside your network needs to reliably find you at the same address every time. Think of a VPN gateway, a remotely accessible server, a CCTV system you check from home, or a piece of line-of-business software that whitelists specific IPs for security. If the address keeps shifting, those connections break or need constant reconfiguration.
Where NAT fits in
Most businesses don't actually have one device per public IP address. Network Address Translation (NAT) is the technology that lets every device in your office (every laptop, phone, printer and server) share a single public IP address when talking to the internet, while each device keeps its own private address internally. This is why a 50-person office can run perfectly well on one public IP for general internet access. NAT handles the translation invisibly in both directions.
The practical upshot: you don't need a public IP per employee, per device, or even per server in most cases. You need one for each service that genuinely has to be reachable from the outside world on its own address, and sometimes you don't even need that if it can sit behind a single gateway with port forwarding or a reverse proxy.
When you genuinely need a static IP
- You're hosting a mail server, FTP server or web server in-house rather than in the cloud.
- You run a site-to-site VPN connecting your office to another location or a remote team.
- A supplier, bank or piece of software requires IP whitelisting for secure access.
- You need remote access to on-site CCTV, access control or building management systems.
- You're running your own domain's DNS or need consistent inbound access for a hosted service.
If none of those apply, there's a good chance a dynamic IP, or at most one static IP for your main gateway, covers everything you need.
How many do you actually need?
This is where the overspending usually creeps in. Some ISPs will quote a block of IPs (a /29 giving five usable addresses, for example) as a default "business" package, whether or not you need them. Before agreeing to anything, work through what's actually pointing to a public address today: your firewall, any VPN endpoints, any self-hosted servers, and any third-party integrations that need a fixed source address. Count those, add a small margin for growth over the next year or two, and that's your real number. Most SMEs end up needing somewhere between one and three static IPs, not a full subnet.
It's also worth checking whether a service you think needs a dedicated IP could instead sit behind your existing firewall using port forwarding, or be moved to a cloud provider that handles its own public addressing. Both approaches can remove the need to pay for extra IPs altogether.
Avoiding the overpaying trap
IP addressing is often bundled into connectivity contracts in a way that makes it hard to see what you're actually paying for each address. It's worth asking your current or prospective provider for an itemised breakdown, and asking directly: "which of these addresses are we using, and for what?" If nobody can answer that clearly, it's a sign the setup hasn't been reviewed in a while, which usually means there's money being spent on addressing nobody is using.
Getting your IP addressing right is a small detail with a direct impact on your connectivity bill and your ability to run VPNs, servers and cloud services reliably. Valetech Solutions reviews connectivity setups for SMEs across Greater Manchester as part of our managed IT and connectivity support, making sure you've got exactly the addressing you need, no more and no less. Get in touch with Valetech Solutions to have your current setup reviewed.