JedWare's profile

Regular Visitor

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14 Messages

Friday, June 10th, 2022 7:23 PM

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ASUS AX86U ISP DHCP Not Working

I had this issue this morning with my internet being down. I searched this forum and saw several threads about causes and solutions. I tried many of the solutions and none worked then I tried one more item and it worked. I am documenting here in case someone else has the same issue.

Searching the forums you will see numerous posts about ISP DHCP issue with ASUS routers. Some saying the DEFAULT method of AGGRESSIVE is the culprit. I tried changing mode to Normal and Continuous but with same results. I tried using MAC Clone and it also did not work. I did numerous power cycles between Modem and Router.

The issue was isolated to the comcast modem when I hooked Directly to the modem with my laptop. I power cycled numerous times but I would never get an IP address other than self-assigned in the 169.x.x,x range. I then decided to manually enter ip address and used 10.0.0.2 with mask of 255.255.255.0 for address with Router at 10.0.0.1 This allowed me to log into Comcast Modem. Once I added a DNS entry of 8.8.8.8 I could browse the internet on laptop. I still could not get DHCP to work. 

I then took the Comcast Modem out of Bridge Mode temporarily and it showed the laptop connected as the only device. I then switched the Bridge Mode back ON and it continued to work. I swapped the router cable back in and it still showed as OFF even with reboot but then I went and added the MAC address from Laptop to router and it all started working again.

I am not sure how long this will last but it appears to be an issue on Comcast side with something getting blocked from DHCP in Bridge Mode. You can fake it out with getting one device working and using that MAC on router.

Problem Solver

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948 Messages

3 years ago

I have that same router, there should be a link on routers admin page to fix it, or just redo the connection setup with the router, 2 minute fix…

Regular Visitor

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14 Messages

@jlavaseur​ Tried that too. It went through all questions and was still down. Switching in and out of bridge mode and using same MAC as laptop was only fix for me.

Problem Solver

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948 Messages

3 years ago

So in bridge mode on the gateway, it’s just a modem, no dhcp, the modem should have the ip 10.0.0.1, in standard mode, when you connect the router, you create a double nat situation..

Regular Visitor

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14 Messages

@jlavaseur​ The end result is I am back in Bridge mode with the Laptop MAC as Clone on router, also set DHCP to Continuous for good measure.  It is some problem state the comcast modem gets into that this was the only solution.

Problem Solver

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948 Messages

3 years ago

So if you set the router to obtain a ip automatically, use the router wizard to create a new connection it will probably work, if you have the router set with a ip 10.0.0.1 and the gateway/modem default ip is the same, obviously a problem….

Regular Visitor

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14 Messages

@jlavaseur​ It DIDN'T work to create a new connection. I have it set to obtain automatically. There are numerous posts on this forum and other with different solutions. I am posting mine since I went through all the various options with no success. Here are the various ways to resolve and only last option worked for me:

1. Use Router Wizard to create a New Connection

2. Change DHCP mode from Aggressive to Normal or Continuous

3. Use the Clone MAC option

4. Turn Bridge Mode OFF and Back ON with Laptop and use MAC of laptop as CLONE Address

If option 1 works for you then consider yourself lucky.

Problem Solver

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948 Messages

3 years ago

It worked several times for me and a couple of friends, I am sure you rebooted the gateway and router for the changes to take affect… whatever works for you…

(edited)

Visitor

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14 Messages

3 years ago

I am having this issue as well, ASUS AX11000 router. My internet randomly went out this morning while playing a game and reported this error in connection settings on my router. I did what you suggested and the MAC address spoofing worked.  Nothing else worked.  Tried just about everything I possibly could.  This person giving you the typical turn it on and off again response has reading comprehension issues I guess?

(edited)

Visitor

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14 Messages

3 years ago

So I was able to get connected again without spoofing my computer MAC address.  I hard reset the xfinity modem/router with my router connected and was able to reach my modem IP through my router.  I set bridge mode while connected through my router and it worked.  Spoofing my computer MAC kept reseting in the middle of the night for some reason.  Hopefully this sticks.

(edited)

Regular Visitor

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14 Messages

@user_40c3b2​ I think the key is that you have to turn off bridge mode and then back on. From other forums it appears Xfinity is blocking MAC addresses once something is triggered and most likely the ASUS Aggressive mode is triggering it.

Visitor

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14 Messages

@JedWare@JedWare​ So my internet dropped again in the middle of the night and I had to go through the whole setup again.  I set my DHCP query frequency to normal.  Hopefully that helps so I do not get bothered to fix the internet every morning.

Visitor

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14 Messages

3 years ago

So my internet dropped in the middle of the night again.  I havent had problems for years and now all of a sudden last Monday it started doing this.  Works great all day no problems then just loses connection in the middle of the night and I have to go through reseting and setting it up again.  Not sure what else I can do.  I tried setting the DHCP query to Normal and it did not work.  I guess I need a new modem or something.

Regular Visitor

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14 Messages

@user_40c3b2​ I have mine set to Continuous. Still have MAC spoofing but has not gone down again so far. Lease expires in couple days so will be watching during that transition.

Visitor

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14 Messages

@JedWare​  Ill give continuous mode a shot then, thanks.  Figured it sounded like a worse aggressive mode so I didn't try it. When I looked it up I found this ASUS page that suggests it was introduced because of this issue https://www.asus.com/support/FAQ/1043591.  Fingers crossed

Visitor

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14 Messages

@JedWare​ Settting the DHCP query frequency to Continuous seems to have fixed this issue for me.  I did not lose internet in the middle of the night like I have been. 

Visitor

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2 Messages

3 years ago

Following. Having the same issue for my RT-AC86U. Happened randomly after one day then when the tech came to fix the issue, it happened again after schedule Xfinity maintenance in the area…

Visitor

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14 Messages

3 years ago

Settting the DHCP query frequency to Continuous seems to have fixed this issue for me.  I did not lose internet in the middle of the night like I have been. 

Visitor

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14 Messages

3 years ago

So this issue is still happening.  We had a tech come out and he changed the splitters but because the numbers look fine he cant really do anything else so we had him order a replacement modem.  Hopefully a new modem will resolve this issue.

Regular Visitor

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14 Messages

@user_40c3b2​ What model modem do you currently have?  I too had the issue return and had to turn off and on bridge mode again. I currently have the xb6.

Visitor

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14 Messages

@JedWare​ XB6.  Ordered an XB7 which is stuck in UPS now apparently.  Good times

Regular Visitor

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14 Messages

@user_40c3b2​ I will be curious if your issue gets resolved with XB7. For the time being I have turned off bridge mode and I am in double NAT mode. Stability was more important than anything and this seems to keep everything working regardless of which device gets rebooted.

Visitor

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14 Messages

@JedWare​ The modem ended up being an XB8.  It has been two days and I no longer need to reset the modem every morning.  I noticed that the internet is still cutting out around 3-4 am only now it reconnects really quick and thats it.  So there is still some kind of issue but the modem is able to hold the connection now after the drop.  This did not happen before so I am not sure what might cause this.  Only time it happens is around 3-4 am, never happens during the day or peak times.  Happens once and then works fine after.

Visitor

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14 Messages

Ok so its been a few more days and I am experiencing no issues now.  The internet is working great.  Seems getting a new modem fixed my issues.

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