Solved MAC Clone bug in firmware 3.0.0.6.102_37103-g8c8d7fb_980-gbd310_BB0B, WAN DHCP fails (with workaround)

[pcl04dl3tt3r]

My router is the RT-BE88U. It is the main router in an aimesh. I was experiencing issues with my xfinity gateway in bridge mode and struggled with this for a week thinking the problem was on their end, but narrowed it down to what I believe is a bug in the WAN MAC clone feature in the router. My main symptom was that I could not resolve a DHCP address when using MAC Clone, only with the default hardware MAC.

The first clue was that the xfinity gateway was actually seeing 2 devices, one with each MAC address, when enabled. I tried 10 minute reboots in every which combination to no avail. I was also able to connect a laptop directly to the modem and get DHCP resolution no problem even when changing the MAC.

So today i decided to look at what was going on in NVRAM when MAC clone was enabled and discovered something that stood out as odd. It changes wan_hwaddr_x, wan0_hwaddr, and wan0_hwaddr_x, but not wan_hwaddr. That setting was still the default hardware MAC. So, I set it manually and boom... problem solved. I think this is a bug that might be related to various threads I came across with similar DHCP symptoms.

 

[Crimliar]

Maybe I'm reading this wrongly but. You've not cloned the MAC address from the Xfinity gateway that you are still using to the WAN of the router because having two active devices with the same MAC address would cause problems?
As I said, maybe I'm reading this incorrectly, I've had a hard day, and my head isn't quite straight at the moment!

 

[pcl04dl3tt3r]

Maybe I'm reading this wrongly but. You've not cloned the MAC address from the Xfinity gateway that you are still using to the WAN of the router because having two active devices with the same MAC address would cause problems?
As I said, maybe I'm reading this incorrectly, I've had a hard day, and my head isn't quite straight at the moment!

Basically I just want to be able to use a virtual MAC on the router and have had no problems with that in the past until the more recent firmware updates. For some people they are asked to use MAC Clone as a troubleshooting step when working with their ISP support.

Maybe it's because I'm opted in for beta firmware updates.

 

[pcl04dl3tt3r]

Maybe I'm reading this wrongly but. You've not cloned the MAC address from the Xfinity gateway that you are still using to the WAN of the router because having two active devices with the same MAC address would cause problems?
As I said, maybe I'm reading this incorrectly, I've had a hard day, and my head isn't quite straight at the moment!

The 2 device thing I mentioned was the Xfinity modem seeing the one router as 2 because it was picking up both the virtual and the physical MAC. My router is the only device connected to the modem, but it was seeing two active devices, as if they were connected to a switch/hub. It should only see the virtual/cloned MAC, and I believe this is a symptom of the MAC Clone setting not being applied correctly in NVRAM. Anyways, setting the value manually in NVRAM corrected this and I am resolving an IP now.