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Does AT&T Fiber give you a public IP? (CGNAT, static IP and ports)

Short answer: Yes, per customer reports: AT&T Fiber hands out a dynamic public IPv4, and the gateway's IP passthrough mode passes it to your own router. AT&T's terms keep the right to use carrier-grade NAT, and we haven't found an official statement for Fiber, so this is low confidence. Static IP blocks are a paid add-on you order by phone, according to customers.

Does AT&T Fiber use CGNAT?

Customers report a public dynamic IPv4 on AT&T Fiber. AT&T's terms of service only say it may use carrier-grade NAT; they don't say whether Fiber does. Both sources are cited on the AT&T Fiber ISP page. If your gateway shows a WAN address in 100.64.0.0/10, you're behind CGNAT anyway: tell us.

Static IP on AT&T Fiber

Static block: customers report adding a static IP block to a residential Fiber line by calling AT&T (it can't be ordered online). Reported prices are about $30/mo for a /29 (5 usable addresses) and about $40/mo for a /28 (13 usable). AT&T doesn't publish these prices. See all prices on the static IP price comparison.

Terms, ports and IPv6

Servers: AT&T's acceptable use policy bans running a server only on dial-up accounts, and its terms say a static IP is intended for a network that may include servers. So the terms aren't explicit for Fiber.
Port 25: AT&T's own port-block table lists TCP 25 as blocked outbound (it may be blocked for dynamic IPs), so sending mail straight from home won't work. Inbound 25 isn't listed. See the home mail server guide.
Ports 80 and 443: not in AT&T's published port-block table.
IPv6: AT&T's terms say its internet services support both IPv6 and IPv4.
Upload: symmetrical on every AT&T Fiber plan, per AT&T's plan page.

How to confirm on your line

Follow how to tell if you're behind CGNAT: compare the gateway's WAN IP with your public IP.
Run the checker. Its port test checks a forwarded port from outside, and the report sums up what you can host.

More detail and sources: Does AT&T Fiber use CGNAT? · Can I self-host on AT&T Fiber? · Public IP on AT&T Internet Air (AT&T's 5G home service)

This site sticks to ISP facts. It doesn't review or recommend third-party products or services. Partly based on customer reports; policies change.