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Modem IP gateway address

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Frequent Visitor

Modem IP gateway address

Two weeks ago, Comcast had a two day outage in my area.  Since the service was restored, I can't use a router with my customer-supplied modem.

I can connect a PC (via Ethernet cable) directly to the modem (Linksys CM3016) and it works.  If I connect a router, I lose my Internet connection.  FYI, I've tried this with four different routers, three Linksys routers and  one Netgear router.

When I look at my network properties in Win10 Settings, it says my Default Gateway is 98.215.10.1, and my IPv4 address is 98.215.10.167

I confirmed this by the 'ipconfig' command from the Command Prompt window.

Shouldn't my Default Gateway be 192.168.1.1?

Is that why my router can't connect?

I've been calling Comcast every other day for two weeks.  The phone support wait time tonight is between 2.5 and 3 HOURS.  I've already spend the equivalent of a work day on the phone with Comcast.  

Anyone have any ideas?

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Expert

Re: Modem IP gateway address

Have you tried power cycling the modem after you change the device that is being directly connected to it ?



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Re: Modem IP gateway address

I power-cycle each combination of modem and router.   It has no effect.  I've done a hard reset on each modem and a 30-30-30 hard reset on each router.  I've checked for updated firmware on the routers and the modems.

I've turned MAC address cloning on and off.  I've even tried hard coding the IPv4 address and gateway into my Ethernet adapter.  Two of the routers run DD-WRT, and I've 'tweaked' a number of network settings, trying to find something to allow my router to connect to the Internet.

None of the steps I've described have allowed me to connect a router that works.

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Expert

Re: Modem IP gateway address

O/k try cloning the MAC address of the PC that works into your router's MAC address cloning feature.



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I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!
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Frequent Visitor

Re: Modem IP gateway address

Thanks, but I've tried cloning the PC's MAC address, the modem's MAC address, and the router's MAC address.

None of them worked.

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Frequent Visitor

Re: Modem IP gateway address

I believe my problems stems from routers starting their IP address range from the 192.168.1.1 Default Gateway address.  My router's addressing scheme can't be changed, but Comcast is giving me a Default Gateway IP address of 98.215.10.1, so any address my router tries to assign is 'out of range'.

 

I can't find anyone at Comcast who understands the concept that there's a Default Gateway address problem.  All they do is point fingers at the modem, the router, or both.  If I could get them to assign a Gateway address in the range my router expects, I think the problem would be solved.

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Re: Modem IP gateway address

I have power cycled the modem and router ad nauseum.

 

Three of my customer-supplied modems were declared 'defective' by Comcast.

I took all three of those 'defective' modems to another Comcast subscriber's home, and ALL THREE worked perfectly.  All three connected to a Netgear Nighthawk router for wired and wireless service.

 

When I brought those three WORKING modems back to my home, once again they failed when I connected a router (actually, I tried FOUR different routers on each modem, and ALL failed).

Comcast again said my modems are 'defective' despite the fact that they work on another Comcast line.

 

It has been 29 days since my service worked correctly.  Comcast is fixated on looking towards my customer-supplied equipment and has steadfastly refused to look over their shoulder at their own network.  I believe Comcast's DHCP server is furnishing a Gateway IP address that is outside the range of addresses my router can use.  No one at Comcast is interested in my theory.  All I get when I call them is 'power cycle your modem' support.  The reps have a script and have no idea how to solve a problem that deviates from their script.

 

My current contract is up in about 10 days.  I've gotten a quote from WOW! Internet to supply service to the 30 apartments in this building.   It's looking more and more like Comcast is toast.