Using a third-party router with AT&T Fiber requires a documented BGW arrangement and attention to TV or voice service dependencies.
Before you change anything
This is a diagnostic entry point. The source supports the general check, not a confirmed root cause for your device.
What to check first
What is the exact ISP gateway model and current routing mode?
Record the exact model, hardware revision, firmware and recent change before adjusting settings. If you cannot answer the question, keep the cause open.
Narrow the likely path
| Observation | Next check |
|---|---|
| Adding a second router | Check for double NAT and whether AP mode or a documented gateway mode fits. |
| Service changed after bridge/passthrough | Restore saved cabling and verify TV/voice as well as internet. |
| Menu is absent | Check provider policy; some gateways cannot expose that mode. |
Decision after the first test
Check the BGW gateway model, current routing path and whether IP Passthrough is appropriate before changing firewall or DHCP settings.
Use a documented next step
Verify before escalating
After each change, repeat the exact failed task. If the result is unchanged, restore the previous setting and use the official support link for your exact hardware revision. Don’t assume a menu or capability from a related model.
Official sources
- AT&T DMZ+ article with BGW210/BGW320 passthrough section (full_text; checked 2026-11-01)
Check your exact US model, hardware revision, and firmware on the linked support page before changing settings.