How passthrough works with the gateway still required
With AT&T, the gateway stays in the path. In IP Passthrough, AT&T says the gateway shares its dynamic WAN IP address with a single device on the LAN, and that it is often used to connect third-party networking equipment such as a router, as an alternative to bridged mode. [1]
AT&T lists three things to know first: only one device can be in passthrough mode; that device loses the firewall protection of the AT&T gateway; and because it gets a WAN IP rather than a LAN IP, other devices still connected to the gateway may no longer share files with it. [1] In practice that means everything goes behind your router, and your router's firewall is the one protecting the house.
Gateway-side settings, from AT&T's article
AT&T's step-by-step article, on its business support site, is written for Motorola NVG510 and NVG589 gateways, with a separate DMZplus procedure for 2Wire and Pace models, and the page says it was last updated on December 7, 2022. [1] AT&T's IPv6 equipment list also names gateways the article does not cover, including the BGW320 and BGW210. [2] Menu labels on those models may differ from the article, so look for the same settings by name.
- Connect a computer to the gateway with an Ethernet cable and open 192.168.1.254 in a browser. [1]
- Open the Firewall tab, then IP Passthrough. Enter the Device Access Code if prompted. [1]
- Set Allocation Mode to Passthrough. [1]
- Set Passthrough Mode to DHCPS-fixed and enter your router's WAN MAC address in the Passthrough Fixed MAC Address field. [1]
- Select Save, then Restart Now when the gateway prompts you. [1]
- Power-cycle your router so it requests a fresh address. [1]
Passthrough modes compared
| Mode | What AT&T says it does | Use it when |
|---|---|---|
| DHCPS-fixed | Gives the public WAN IP to the device whose MAC address you specify; that device must use DHCP. AT&T recommends this option. [1] | Almost always: one router, known MAC |
| DHCPS-dynamic | Gives the WAN IP to the first LAN device that requests a DHCP address. [1] | Only if the router is the sole device ever plugged into the gateway |
| Manual | You enter the WAN IP, gateway and mask from AT&T customer care; connectivity is lost if the gateway gets a different WAN IP. [1] | Rarely; AT&T recommends DHCPS-fixed instead |
| Default Server | Forwards externally initiated TCP and UDP traffic to one LAN device, which keeps its LAN IP. [1] | Not for a router; this is a DMZ-style option |
| DMZplus (2Wire/Pace) | The passthrough equivalent on those gateways; the device must use DHCP and connect directly. [1] | Older 2Wire and Pace gateways |
Router WAN settings
- Cable a LAN port on the gateway to your router's WAN port.
- On a GL.iNet router, open INTERNET, then Ethernet, and keep the protocol on DHCP, which is the default and what DHCPS-fixed requires. [3][1]
- Find the router's WAN MAC address before you set up the gateway. GL.iNet shows the MAC mode and address under the Ethernet Port settings. [3]
- Leave VLAN ID empty; it is only needed if the provider requires a tagged VLAN. [3]
- Address ranges do not clash by default: the AT&T gateway uses 192.168.1.254 and GL.iNet routers use 192.168.8.1. [1][7]
- For IPv6, AT&T says third-party routers need to be IPv6-compatible and points you to the router's manufacturer. [2]
Turn off the gateway's Wi-Fi
AT&T's passthrough article does not cover the gateway's wireless settings. [1] If the gateway keeps broadcasting, devices that join it end up beside your router rather than behind it, without the protection or features your router provides, and two networks compete for airtime.
Look for the wireless settings in the gateway's own web interface at 192.168.1.254 and turn its Wi-Fi off once your router's Wi-Fi is working, or ask AT&T support how to do it on your model. Keep a note of the original network name and password in case you need to switch back.
Verify it worked
GL.iNet's check is the most direct: read the WAN IP in the router admin panel and compare it with a "what is my IP" search. Matching addresses mean your router holds the public IP. [4]
| What the router WAN shows | Meaning | Next step |
|---|---|---|
| Same address as "what is my IP" | Passthrough is working [4] | Set up port forwarding or remote access on your router [5] |
| 192.168.1.x | Router is still a normal LAN client of the gateway | Recheck the MAC address entered on the gateway; restart both devices [1] |
| No address, or connected without internet | Router not receiving DHCP | Confirm WAN protocol is DHCP and the gateway shows Internet up [3] |
Maintenance notes
- A restart is safe: AT&T says to unplug the gateway for 20 seconds and allow up to five minutes for it to come back. [6]
- A factory reset is not: holding the red reset button for at least 15 seconds returns the gateway to factory settings and deletes custom settings. Note your passthrough settings before any reset. [6]
- If you replace your router, its WAN MAC address changes. Update the Passthrough Fixed MAC Address on the gateway, or the new router will not receive the public IP. [1]
Questions before you decide
Is IP Passthrough the same as bridge mode?
No, but AT&T describes it as commonly used as an alternative to bridged mode. The gateway still connects to AT&T and shares its dynamic WAN IP with a single LAN device, which gets a WAN address instead of a LAN address.
Which passthrough mode should I choose?
AT&T recommends DHCPS-fixed. You enter your router's WAN MAC address and the router must be set to obtain its address by DHCP. Manual mode requires you to type the WAN details yourself and breaks whenever the gateway receives a different WAN IP.
How do I know passthrough worked?
Read the WAN IP on your router's status page and compare it with a "what is my IP" search, as GL.iNet's guide describes. If they match, your router has the public address. If it shows a 192.168.1.x address, it is still behind the gateway's NAT.
What happens if the gateway is factory reset?
AT&T says a reset returns the gateway to factory settings and deletes custom settings, and suggests noting them first. Expect to redo the passthrough settings after a reset; holding the red button for at least 15 seconds triggers it.
Sources & verification
Product details and prices can change. Check the linked provider before buying.
- AT&T Business Support: Configuring IP Passthrough and DMZplus Accessed 30 Oct 2026
- AT&T Support: IPv6 and AT&T Internet services Accessed 30 Oct 2026
- GL.iNet Router Docs 4: Ethernet (WAN) Accessed 30 Oct 2026
- GL.iNet Router Docs 4: How to check if your ISP assigns you a public IP address Accessed 30 Oct 2026
- GL.iNet Router Docs 4: Port Forwarding Accessed 30 Oct 2026
- AT&T Support: Restart or reset your AT&T All-Fi Hub or Wi-Fi gateway Accessed 30 Oct 2026
- GL.iNet Router Docs 4: Connect to a hotspot with a captive portal Accessed 30 Oct 2026
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