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AC68U/AC86U unable to get a WAN IP address from modem (in bridge mode)?

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Occasional Visitor

While setting up my new modem (Motorola MG8702 which is a WIFI router/modem combo; family member bought this several months back and only now have I had a chance to work on it), I was trying to put it into bridge mode and unfortunately each time I tried with an AC68U or AC86U, the ASUS routers seem to not register the WAN IP address and therefore no internet is available. I have Comcast Xfinity and I'm not sure if the modem is just problematic or the routers are not configured properly to accept the WAN IP address coming from the router (assuming the modem works in bridge mode in the first place). I made sure the routers are set to automatic WAN IP address mode.

I eventually gave up and opted to not do bridge mode and configured a static IP address for the router within the modem and then put it into DMZ mode. Not ideal but it seems like it was the only way to get internet working and be able to access my VPN server on the ASUS routers.

Has anyone else here experienced a similar issue?


Part of the Furniture
What can sometimes happen is that the previous router's MAC address on the WAN can become "locked" to the ISP, usually because you didn't formally release the existing DHCP lease on the WAN. So when you install the replacement router, as far as the ISP is concerned, you're attempting to have multiple public IPs! Besides formally releasing the prior DHCP lease, you could clone the MAC address of the prior router's WAN to the new router's WAN so it appears to the ISP to be the same router.


Occasional Visitor
Hmm, I see. I thought that might be a non issue if I power cycled both the modem and router but I'll have to give it another shot with that in mind. Thanks.


Occasional Visitor
Just following up on this just to provide closure. I was finally able to get around to fixing this (since this was in a remote location and couldn't easily troubleshoot it from far away). I release the WAN as you mentioned and after a few attempts, was able to get it working. Thanks again!

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