[SOLVED] Motorola MB8600 modem not connecting to internet via Netgear AC1750 router

[xazzu]

Hey all - been fiddling with this all day to no avail, and had to go back to my old set up until I can get it figured out.

Current modem from Spectrum through the router works fine, no issues and all internet works.

Switch to the new router, the MB8600, via Spectrum website and it works fine hardwired to the PC. Try to plug in via the router and no internet. The "troubleshoot" error says the modem isn't working.

Went back to the original modem and no issues. No cables were moved off of the router and all connections were checked.

What am I missing? It has to be something dumb.

Diagram as requested by Ralston18, using the names of the ports on the devices:
ISP (Spectrum) === (coax) ===> MB8600 Modem [Ethernet port] ----->[Internet port] Netgear AC1750 Router [Ethernet port(s)] -----> wired devices and ~~~~ > wireless devices.

 

[Ralston18]

What are the current modem to router to network physical connections?

I would expect something like the following line diagram where -----> represents an Ethernet cable:

ISP (Spectrum) === (coax, DSL, fiber) ===> MB8600 Modem [LAN/Ethernet port] ----->[WAN Port] Netgear AC1750 Router [LAN port(s)] -----> wired devices and ~~~~ > wireless devices.

Feel free to edit and correct my line diagram as necessary.

Spectrum MB8600 modem should have its' Router functions (DHCP) disabled. Only the AC1750 Router should be providing DHCP IP addresses and managing any Static IP addresses for your network devices.

 

[kanewolf]

Hey all - been fiddling with this all day to no avail, and had to go back to my old set up until I can get it figured out.

Current modem from Spectrum through the router works fine, no issues and all internet works.

Switch to the new router, the MB8600, via Spectrum website and it works fine hardwired to the PC. Try to plug in via the router and no internet. The "troubleshoot" error says the modem isn't working.

Went back to the original modem and no issues. No cables were moved off of the router and all connections were checked.

What am I missing? It has to be something dumb.

Since you had the modem connected directly to your PC, spectrum has "remembered" the MAC address of the PC. You need to contact spectrum customer support and tell them you are swapping routers and need your line reset. That way the MAC address from your PC is forgotten and the MAC address of the WAN on the router will be picked up.

 

[xazzu]

What are the current modem to router to network physical connections?
...
Spectrum MB8600 modem should have its' Router functions (DHCP) disabled. Only the AC1750 Router should be providing DHCP IP addresses and managing any Static IP addresses for your network devices.

I've edited the OP for the diagram.

The modem doesn't seem to have any functions available that I could see when I had it connected to the PC; I checked the Advanced area but it was very minimal.

Since you had the modem connected directly to your PC, spectrum has "remembered" the MAC address of the PC. You need to contact spectrum customer support and tell them you are swapping routers and need your line reset. That way the MAC address from your PC is forgotten and the MAC address of the WAN on the router will be picked up.

I was wondering about this as I had seen some mentions about MAC addresses in my searches. I did try to clone the PC address but that didn't change anything. I've set everything back to the original setup (since I need the wifi for work) for now but they do still list the new modem in my devices. Neither of the two folks I spoke with at Spectrum, after mentioning the MAC, didn't seem to think that was an issue.

 

[kanewolf]

I've edited the OP for the diagram.

The modem doesn't seem to have any functions available that I could see when I had it connected to the PC; I checked the Advanced area but it was very minimal.




I was wondering about this as I had seen some mentions about MAC addresses in my searches. I did try to clone the PC address but that didn't change anything. I've set everything back to the original setup (since I need the wifi for work) for now but they do still list the new modem in my devices. Neither of the two folks I spoke with at Spectrum, after mentioning the MAC, didn't seem to think that was an issue.

Does the status page on the router show a WAN address?
Are you using the same ethernet cable when you connected the PC and router?

 

[xazzu]

Does the status page on the router show a WAN address?
Are you using the same ethernet cable when you connected the PC and router?

It did not originally, though there's been a change now.
Yes, same cables, no changes.

UPDATE: I tried everything again today, using the clone MAC on the router. Started up modem, waited. Router, waited. PC, no connection until "troubleshooting" and it reset the ethernet adapter. Now internet (hardwired through the router).

However, I'm getting no wifi on our phones but am on my work laptops. Should I clone the MAC address of wifi as well?

 

[kanewolf]

It did not originally, though there's been a change now.
Yes, same cables, no changes.

UPDATE: I tried everything again today, using the clone MAC on the router. Started up modem, waited. Router, waited. PC, no connection until "troubleshooting" and it reset the ethernet adapter. Now internet (hardwired through the router).

However, I'm getting no wifi on our phones but am on my work laptops. Should I clone the MAC address of wifi as well?

There is NO reason to clone the PC MAC address. IMO, you don't want that. You want to use the real MAC address of the router.
Don't clone any MAC addresses.
The phones could be a number of things.
I would start by verifying the WIFI settings of the router. Channel number for 2.4 and 5Ghz and channel width for each.
The most universal settings are channel 1, 6, 11 for 2.4Ghz with 20Mhz channel width. Channel below 50 for 5Ghz with 40Mhz channel width. MANUALLY set those things and test.

 

[xazzu]

There is NO reason to clone the PC MAC address. IMO, you don't want that. You want to use the real MAC address of the router.
Don't clone any MAC addresses.
The phones could be a number of things.
I would start by verifying the WIFI settings of the router. Channel number for 2.4 and 5Ghz and channel width for each.
The most universal settings are channel 1, 6, 11 for 2.4Ghz with 20Mhz channel width. Channel below 50 for 5Ghz with 40Mhz channel width. MANUALLY set those things and test.

I removed MAC cloning and restarted everything to test and we are now in business. Maybe Spectrum needed to just...I don't know?

Wifi is working fine now as well. Maybe the MAC stuff was causing some issue. I hate when the 15th restart works but hey, what do I know.

Thanks all! I upvoted and selected a "best answer" even though it was a group effort.

 

[bill001g]

Cable modems can be very picky. You most times have to boot the cable modem with nothing connected and then it will lock the very first mac address it sees connected to it.