Static IP Addressing vs Dynamic IP Addressing

Static IP Addressing vs Dynamic IP Addressing. Two common terms that are often bandied around are “static” and “dynamic” when referring to IP addressing. Here we hope to explain what these terms mean.

Put very simply, a static IP address is exactly as the name suggests – it is fixed. A dynamic address is an address that is assignable on demand, normally existing in a large pool of other moveable dynamic address.

At a local level, this means that addresses on your network can be fixed, so if you wanted your mail server or switch to have a permanent address on your network you would give it a static address. In cases where it is less important to have fixed addresses, such as for guests signing onto your wireless network, you would have a pool of dynamic address that are dished out on first come, first served basis, using a service such as DHCP.

At a wider level, this applies to how you obtain your IP address from your service provider. A fixed static address means that your IP address on the internet always remains the same — either you will have configured your router to have a static address or your ISP will have your static IP on record and will issue it to you every single time (called consistent serving). If your ISP is not doing that, then you will be receiving a dynamic IP address (normally this applies to residential, non-commercial internet connections). This means that whenever you reboot your router and a new connection is made to your provider, you could potentially be issued a different IP address from the dynamic pool.

Both methods have their pros and cons. Generally it is better to have a static IP address on your WAN interface because this makes wider routing and services much easier to administer. Indeed in some cases, such as VPN tunnels, using a particular service without a static IP address can be very difficult. Dynamic IP addressing is much easier to administer from a local network admin perspective, so this is much more preferable in situations where you just need a bunch of clients to connect and disconnect as they please.