Need Help: Deco Mesh + AT&T BGW320 IP Passthrough Not Working — Still Getting 192.168 IP
Need Help: Deco Mesh + AT&T BGW320 IP Passthrough Not Working — Still Getting 192.168 IP

Hi TP-Link Support — I’m reaching out after two days of trying to get my Deco mesh system working as the primary router behind my AT&T BGW320 fiber gateway. Despite following all setup steps and confirming passthrough is active, the Deco is still getting a private IP.
🔧 System Setup:
- ISP: AT&T Fiber 1000 Mbps
- Modem/Gateway: AT&T BGW320
- Mesh System: TP-Link Deco (3-unit system; main unit hardwired)
- Mode: Deco is set to Router Mode
- Internet Type: Dynamic IP (DHCP) selected during setup
✅ My Goal:
- I want Deco to act as the sole router in my home.
- I’m trying to use IP Passthrough from the BGW320 so Deco receives the public IP and manages all traffic (no double NAT).
🔁 What I’ve Already Done:
- Reset all Deco units and factory reset BGW320
- Set BGW320 to:
- IP Passthrough Mode: Enabled
- Passthrough Type: DHCPS-fixed
- MAC Address: Selected Deco from device list
- Saved and rebooted
- Disabled AT&T Wi-Fi radios (2.4 & 5 GHz)
- Main Deco connected to BGW320’s yellow LAN port
- Power cycled in proper order: unplug Deco → reboot BGW320 → wait 2–3 mins → plug Deco back in
- Waited for full boot and checked Deco’s internet IP
⚠️ Problem:
- Deco never gets the public IP from AT&T. It always shows a private IP like 192.168.1.75
- Meanwhile, the BGW320 shows passthrough is active, and displays the correct public IP (45.17.16.127)
- Deco is the only LAN-connected device during setup (no switches, no other active connections)
- I also unplugged my Vivint Smart Drive, which was previously on the network, in case it was grabbing the lease
📷 What I See:
- On BGW320:
- IP Passthrough: On (public IP address)
- IP Passthrough Address: 45.17.16.127
- In Deco app:
- IP address is always 192.168.x.x (private) — never updates to public IP
❓My Questions:
- Is there a known issue where Deco doesn’t accept a public IP via passthrough from AT&T gateways?
- Could there be a DHCP timing conflict where Deco isn’t requesting the IP fast enough?
- Is there a way to force Deco to release/renew WAN lease or spoof a MAC address to match the one BGW320 expects?
- Does Deco require any VLAN tagging or other custom config for this to work on AT&T?
Any help would be appreciated. I’d love to avoid having to bypass the BGW320 altogether if I can get this working properly through standard passthrough.
Thanks in advance.
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@jzchen question was it 30-40 seconds after plugging in ATt router then plug in deco or was it once the ATt router showed connected 30-50 seconds after that point
jzchen wrote
@Suoravat I hope you were able to get IP Passthrough to work by my workaround. (I had to fix getting a private IP last couple of days and I would say 30 seconds may be conservative and 40 seconds may be worth a shot. But it took me a couple of tries and I did not use a stop watch)...
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Don't know if this will work for you, but I'll tell you what worked for me (with some difficulty). After struggling for the last few weeks, instead of using DHCPS-Fixed, I used the the dynamic option. After rebooting both the gateway and the Decos, it finally gave me the proper address showing on both AT&T's side and Deco's side. However, I still have issues where it will randomly reset every few days to displaying a private address. However, I just repeat the steps again and it works. So maybe try Dynamic?
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@itschristian07 It used to be AT&T gave a 24 hr DHCP lease time, and my network was active enough that the WAN IP assigned never went back to the IP pool. They switched to 1 hr, BUT I still haven't changed WAN IP. You can manually assign (the WAN IP as a static IP). Worse comes to worse the IP address goes back to the pool and your service stops...
I'm pretty confident you can get it dynamically assigned as I instructed. Mine is a BE95 and may have a longer boot up time, but I guess you can try 20 secs, 25 secs, 30 secs. Eventually you will get it. Then just do the same next time. I just have a good time sense so I just wing it without a stopwatch...
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