AT&T Fiber provides support for static IP blocks. However, people don’t order them frequently enough to provide an automated process for ordering them, or documentation explaining how to configure them. This blog should help.
If you’re running a home lab with servers or maybe hosting a personal site, a static IP block can give you the flexibility to assign unchanging public IP addresses to your servers. I recently set up a static IP block on my AT&T Fiber connection using the Nokia BGW320-505 router, and I’m here to walk you through the process. Whether you’re exposing servers for remote access or building a robust network, this guide will help you configure your static IP block with confidence.
Why use a static IP block?
Static IP blocks are perfect for home labs or small networks. They provide a range of public, unchanging IP addresses you can assign to devices, bypassing NAT for direct internet access. For example, with AT&T Fiber, you might get a /28 block, giving you 13 usable IPs for your servers, switches, or even a pfSense firewall. This is great for:
- Hosting websites or services (like my OpenShift cluster).
- Remote access to iDRACs or other management interfaces.
- Running public-facing applications without port forwarding headaches.
Understanding IP Block Sizes
Before diving into the setup, let’s break down common IP block sizes AT&T offers. The table below shows the CIDR notation, subnet masks, total addresses, and usable addresses after accounting for AT&T’s reservations (network, broadcast, and one extra for their gateway).
| CIDR | Subnet Mask | Total Addresses | Usable Addresses |
|---|---|---|---|
| /29 | 255.255.255.248 | 8 | 5 |
| /28 | 255.255.255.240 | 16 | 13 |
| /27 | 255.255.255.224 | 32 | 29 |
How it works:
- CIDR: The number (e.g., /28) indicates how many bits are in the subnet mask. A /28 means 2^(32-28) = 16 total addresses.
- Reserved Addresses: AT&T reserves three addresses: one for the network, one for the broadcast, and one for their gateway.
- Usable Addresses: Subtract the reserved addresses. For a /28, that’s 16 – 3 = 13 usable IPs.
For my home lab, I chose a /28 block, giving me 13 IPs for my Dell servers, Cisco 1Gbps switch, Mellanox 100Gbps Infiniband switch, Dell 100GbE switch, and Mellanox NICs. A /29 might suit smaller setups, while a /27 is overkill unless you’re running a mini data center!
Ordering a static IP block
AT&T Fiber has a few pages explaining static IP blocks, but it’s not really clear how to do it. Basically, you have to contact support, which provides you with an automated set of options. You need to talk to a live person, so you need to navigate to where you want to order service or support so that you can talk to a live person.
They will check your account and ensure that you have a router that can support a static IP block. You tell them what block size you want. Then, they will give you the IP address range. In my case, it was not active right away. For some reason, they do a truck roll to your house, and a technician will check out your router and your internet connection, and then provide you with the relevant information about your static IP block.
The thing is, they do not set it up for you. It’s possible you’ll get a technician who knows how to do it. I wasn’t so lucky. My technician indicated that much of his job is “compliance”, and that they do the truck roll to ensure you have a proper connection and proper router. So the rest is up to you.
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