DHCP Issue

I have an Asus RT-AC68U wifi router that connects to my modem (Motorola MG8702) via ethernet cable. This setup worked fine for years. A few days ago, the Asus router reported that it cannot connect to WAN, and the status read "Your ISP's DHCP does not function properly". In the internet status page of the Asus wifi router, connection type set to "Automatic IP", WAN IP reads 0.0.0.0, lease time says "renewing...", and lease expires says "expired". Meanwhile, my internet connection via the modem is working properly. I tried MAC clone without success. Further research brought me here, other people who had similar issue reported a "provisioning" seem to resolve the issue. I am hoping this would solve mine as well, I appreciate the help.

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EG

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112.7K Messages

2 days ago

First. The MG8702 already has a built-in router. Do you have it set to bridge mode ?

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user_ikzfph

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3 Messages

That's correct. The MG8702 is the primary network not in bridge mode, and I setup the RT-AC68U as a second network not in bridge mode.

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2 days ago

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EG

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112.7K Messages

2 days ago

I don't think that I'm being clear. The 8702 needs to be in bridge mode, otherwise

you are cascading 2 routing devices, which will result in an undesirable "double NAT" condition on your home network.

Google "double NAT" for info about its potential pitfalls. It may break some applications.

Also. This may seem silly, but have you tried power-cycling the 8702 and the Asus lately ? And you would have needed to power cycle the 8702 after you cloned a MAC address into the router.

Proper power-cycling order;
Shut down the computer connected to the router.
Power down / unplug the modem and the router.
Allow them to sit for 60 seconds unplugged.
Plug in the modem first and allow it to completely boot up until the indicator light(s) on it show a steady connection (lit steadily).
Plug in the router and let it fully boot up and sync with the modem.
Start the computer and allow it to completely boot up.
Any joy ?

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user_ikzfph

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3 Messages

Thanks for your response, EG. I set the 8702 to bridge mode, power cycling as outlined, and only connect 1 ethernet cable from the 8702 to Asus, and the Asus was still not connected to WAN.

To further elaborate my use case:

The 8702 (modem/router combo) is connected to Xfinity via coax. This network is mainly for guest and streaming devices.

The Asus is a wifi router, that I have been using it in DHCP mode and setup Surfshark via OpenVPN protocol. I connect personal devices to this network, both wired and wireless.

I understand this setup causes double NAT, and for the past 6 years it has not given me issues. In the past month, I noticed more frequent connection drop on the Asus network (while connected to VPN on the router). My area (southeast Georgia) recently experienced severe weather, and power outage became more frequent. Then one day the Asus network failed to connect to WAN, and remained until now.

I pushed the Asuswrt-Merlin firmware to the Asus router with no success on the WAN. With the Merlin firmware, it offers the VPN director option that I can try to route devices to or bypass VPN. (More to learn...)

Perhaps this setup is nearing the end of its service life? It appears it is not the "proper way" to go about having a unencrypted network and a secured (VPN) network at home. It seems the proper way would be upgrading to a router that supports split tunneling.

Your insights and suggestions are greatly appreciated.

(edited)

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2 days ago

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Your Home Network

user_ikzfph

DHCP Issue

EG

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EG

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