Replaced Modem and now my Router gives me this: Your ISP's DHCP is not functioning properly

I received and installed the Arris T25 today, it is working fine but the router is still giving me the same message: "Your ISP's DHCP is not functioning properly"

I plugged the modem directly into my laptop and I was able to hook into the internet without issue. 

When I try the same, plugging the modem directly into my desktop I get this: "Ethernet doesn't have a valid IP configuration"

I am at my wit's end if anyone can help me I would be very grateful. 

You need to properly power cycle / reset the modem each and every time that you change the device that is being directly connected to it.

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@Hepkat wrote:

Hi there EG,

 

I too am suffering through this issue that the OP and many others have experienced..  When briged I get the error message the OP stated.

 

FWIW, your situation and the OP's are not exactly the same as they are using separate components (a straight cable modem and a stand-alone router), where you are using a combination modem / router, gateway device. 

 

I am able to use my new rotuer if the modem is set to routed and not bridged.

 

Yes. We've seen a lot of posters here with that issue and so far, we haven't seen a solution. It seems to be a firmware glitch.

 

***UPDATE***

After much trial and error, there are a few things I have noticed and one of the reasons I ask about this of EG.

I think it is safe to say that we should not only rely on the reset this modem may do when updating the gateway to bridge mode.. I noticed that allowing the changes to take effect and allowing the modem to fully reset and power up, THEN forcing a power cycle by unplugging the modem physically for a good 20 seconds helped in my case for now..all the while the router was fully powered on during.

 

I hope all the best to the OP in resolving this issue, it is frustrating for sure and no one wants a double NAT situation.

 

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I couldn't find a MAC Cloning option. At this point, I am going to reset my PC, out of fear of this being a Malware thing, and see where that gets me.

Hi there EG,

Just for context, in this post your are placing much emphasis on properly power cycling/resetting the modem each time you change the device connected to it.

I too am suffering through this issue that the OP and many others have experienced.. I am able to use my new rotuer if the modem is set to routed and not bridged. When briged I get the error message the OP stated.

Prior to today, with another router prior to the one I have now, I was abe to leave that other router connected to the modem overnight and then the next day the router would be assigned the ISP but this did not happen with this new router I am using. I am hoping that ComcastChe can maybe assist..

Not trying to hijack the OP's thread but did want to ask about what the correct steps of power cycling entail for clarity in the event that myself or the OP are not following those exact steps?

***UPDATE***

After much trial and error, there are a few things I have noticed and one of the reasons I ask about this of EG.

I think it is safe to say that we should not only rely on the reset the modem may do when updating the gateway to bridge mode..

I noticed that allowing the changes to take effect and allowing the modem to fully reset and power up, THEN forcing a power cycle by unplugging the modem physically for a good 20 seconds helped in my case for now..all the while the router was fully powered on during.

I hope all the best to the OP in resolving this issue, it is frustrating for sure and no one wants a double NAT situation.

Did you try the cloning tip ? Did you power cycle the modem after you cloned the MAC address of the laptop into the router ?

If that router has a MAC address cloning feature, try cloning the MAC address of the laptop that works into it.

There may be something wrong with the modem where it is not forgetting the MAC address of the previous device that was connected to it as it should do after a power cycle operation is performed. By doing this you are tricking the modem in to thinking that it is still connected to the laptop that works. Good luck !

No luck here.

When I look at the View hardware and connection properties on my desktop PC the DHCP lease obtained says Wednesday, December 31, 1969, at 7:00:00

It gives a lease expiration of the same date.

I reset Windows and that did nothing to help. I wish I hadn't pulled that lever but regardless I have to get this fixed and so far nothing has worked.

I encountered the same problem with a Netgear CM2000 modem and a Asus RT-AX3000 Router, but I couldn't find any solution on the internet.

The router would report "Your ISP's DHCP does not function properly".

I am able to solve this problem and here is my solution.

1) Disconnect WAN cable from Router.

2) Connect your computer with the Modem (CM2000 in my case) and check if the internet is working (it should work). Disconnect the cable after checking.

3) Connect your computer (I have a laptop) to the router through LAN1.

4) Log into the router through the internet browser with the address: 192.168.50.1 

5) Under "Advanced Settings" on the left sidebar, click on WAN. Then, go to the "Internet Connection" tab.

6) Under "Special Requirement from ISP", in the "MAC Address" section, click on "Mac Clone" .

7) Under "Special Requirement from ISP", in the "DHCP query frequency" section, choose "Continuous Mode" .

8) Click Apply and wait.

9) On the top of the page, click Reboot; and wait.

10) Connect your modem to the router's WAN port.

11) Connect your devices to the router and enjoy your internet. 

My Asus Router firmware version: 3.0.0.4.386_42095.

I also attached my router's internet connection setting page here as a reference. I hope this helps!

Thanks for posting ! Year old dead thread now being closed.