Configure AT&T BGW IP Passthrough Without Blanket Firewall Disabling

BGW210/BGW320 section of the AT&T guide; firmware/UI must be matched.

Applies to: BGW210/BGW320 section of the AT&T guide; firmware/UI must be matched.

Checked: 2026-11-01 · Risk: high-impact · Status: source-grounded editorial draft; not hands-on tested.

Before you begin

Record the gateway configuration, your router’s WAN MAC and both LAN subnets privately. Preserve local access. This is not a claim of pure Layer-2 bridge operation.

Procedure

1. Connect the personal router using the documented gateway LAN path and identify its WAN MAC locally.
2. Open Firewall > IP Passthrough in the supported BGW interface.
3. Select Passthrough for Allocation Mode and DHCPS-fixed for Passthrough Mode.
4. Select the personal router’s WAN MAC as the fixed target, save and apply the vendor’s restart instructions.
5. Check the downstream router’s WAN result before changing any other gateway feature.

Verify the result

The intended downstream router receives the expected passthrough address and internet works. Separately test AT&T-dependent services.

Undo or recover

Restore the recorded allocation/target settings and original wiring; use the exact current UI rather than an assumed reset timer.

Stop and escalate

Resolve subnet overlap or service dependency with AT&T support instead of disabling every firewall setting.

Evidence and interpretation limits

The source is a DMZ+/speed-workaround article. Its blanket firewall-switch changes are intentionally not copied as universal prerequisites.

The steps above combine paraphrased official instructions with an original safety and test workflow. They are not a verbatim manual, a guaranteed fix, or evidence of a common hardware defect.

Official sources

• AT&T DMZ+ article with BGW210/BGW320 passthrough section — att-passthrough; access: full_text.

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