CM1000 is not talking to routers over Ethernet

[Ghery]

I bought a CM1000 from Best Buy this afternoon.  This is to replace a Motorola cable modem I've had for a number of years with something faster.  After a bunch of fooling around with Comcast the CM1000 is talking to their network.  It is not, however, talking to my network.  The only exception is if I connect a laptop directly to the CM1000.  The Ethernet light is red unless only a single computer is connected.  Not acceptable.  Any ideas before I take this thing back to Best Buy?  Netgear's support stinks as it is only available during certain hours and they want "Proof of Purchase", which downloads from Comcast in a format that this website will not accept.

[antinode]

> [...] After a bunch of fooling around with Comcast [...]

   Not much meat on that bone.

> [...] It is not, however, talking to my network. [...]

   And how would it do that?  Through some (unspecified, secret(?))
router or other?

> [...] The Ethernet light is red unless only a single computer is
> connected. [...]

   Any "a single computer", or one specific "a single computer"?

      https://community.netgear.com/t5/x/x/m-p/1574972

[Ghery]

Snarky replies aren't very helpful...

"talking to my network" means just what you suppose it means - through the Ethernet connection.  Connect it to either router or the switch and you get a red light.  Connect the cable modem directly to the laptop I'm using and you get a green light.  Red light = no joy in communicating with anything over Ethernet.

[antinode]

> Snarky replies aren't very helpful...

   Not answering specific questions is what's really unhelpful in these
situations.  Along with information-free problem descriptions.

> [...] Connect it to either router or the switch and you get a red
> light.

   Still wondering what that mysterious "router" might be,

   And what is your "the switch"?  Connecting a modem directly to a
network switch would very likely cause trouble with multiple client
devices.  Why involve it, whatever it is?

> [...] Connect the cable modem directly to the laptop I'm using and you
> get a green light. [...]

   Yeah, I got that the first time.  Hence the other (still unanswered)
questions.

[Ghery]

Cable Modem -> Router (provided by Comcast) -> Router (provided by me) -> Gigabit switch.

Various computers are connected to the second router and the switch, either via Wifi or Ethernet for the router and Ethernet for the switch.  The first router provides WiFi connectivity for the Comcast security system and nothing else.  Breaking the chain and connecting any of the routers or switch to the cable modem results in the light going red.  Connecting a computer directly to the Ethernet port on the cable modem results in a green light and communications.

Removing the CM1000 and replacing it with the old Motorola cable modem results in communications for all devices tried so far.

This help?

[antinode]

> [...] Router (provided by Comcast)

   Not a very detailed description of anything.

> [...] Router (provided by me)

   Not a very detailed description of anything.

> [...] Breaking the chain and connecting any of the routers or switch
> to the cable modem results in the light going red.

   With my weak psychic powers, I don't know how any of these routers is
configured, and exactly what you're connecting to what remains a
mystery.  According to the CM1000 User Manual, the "Ethernet LED" should
be green, amber, or off; "red" seems not to be an expected outcome.

> Removing the CM1000 and replacing it with the old Motorola cable modem
> results in communications for all devices tried so far.

   Would it really hurt too much to provide an actual model number for
any of these devices?

>    Any "a single computer", or one specific "a single computer"?
>
>       https://community.netgear.com/t5/x/x/m-p/1574972

   Still wondering.

> This help?

   Not really.  Too many questions remain unanswered.

[Ghery]

Cable modem - Netgear CM1000 (DOCSIS 3.1)

Motorola cable modem - SB6121  (DOCSIS 3.0)

Comcast router (WiFi connectivity for security system) - Netgear WNR1000

General WiFi and Ethernet router - Linksys E2500

Gigabit Ethernet Switch - Netgear GS608

Only the Netgear GS608 has 1000BaseT ability.  The other two max out at 100BaseT.  That should be downward compatible with the CM1000's 1000BaseT capability.  

Rather than saying there's not enough information, ask what you specifically need and I'll go from there.

[antinode]

> [...] ask what you specifically need and I'll go from there.

   I tried that before:

2>    Any "a single computer", or one specific "a single computer"?
2>
2>       https://community.netgear.com/t5/x/x/m-p/1574972

   Twice:

6> >    Any "a single computer", or one specific "a single computer"?
6> >
6> >       https://community.netgear.com/t5/x/x/m-p/1574972
6>
6>    Still wondering.

[Ghery]

You may continue to wonder.  For some reason, known only to Netgear and the others, it is now working.  Don't ask why, I don't know.  Evil spirits (as one of my EE profs would have said "back in the day") are as good an answer as any.  And that red light does look a bit more like orange, which I would expect given that it is connected to a 100BaseT port.

In any case, it's working now.

[antinode]

> [...] For some reason, known only to Netgear and the others, it is now
> working. [...]

   If the original problem was your ISP rejecting the MAC address of the
new router, then a period of disconnectedness might reset its
willingness to accept a novel MAC address, which would allow a
previously rejected gizmo to become acceptable.  You could explore this
hypotheses by connecting different devices to the modem, to see if it
always rejects novel gizmos (computers, routers, ...), which is what I
was trying get you to determine, but I won't hold my breath waiting for
those results.

> [...] And that red light does look a bit more like orange, which I
> would expect given that it is connected to a 100BaseT port.

   Plausible.

> In any case, it's working now.

   Good news is always good news.  Thanks for the report.

[SSJDUSTEN]

Alright I will pose a question with some specifics. 

Cm1000 plugged directly into my Alienware R6 computer through ethernet cable. WIFI is turned off on the PC. Orbi rbk50 two pack mesh system. 

Modem and Orbi are talking correctly, and things connecting through wifi are fine. The moment I connect a wired device to the orbi router, the amber ethernet light on the modem turns on and all other lights turn out. Internet is now lost. Orbi system is glowing Magenta for no internet connection. 

Test 1. Xbox one wired connection = orange light. 

Test 2. Playstation 4 wired connection = orange light

Test 3. Computer  wired connection = worked fine everything good

Test 4. Hue Bridge via ethernet = worked fine

Test 5. With computer, Hue bridge connected via Ethernet, I put in the playstation 4 and it went back to orange. 

Unplugging the modem and letting it boot back up without the PS4 or Xbox gets it back to working order. 

Conclusion. The moment something is connected to the ORBI router other than PC and Hue bridge, it seems to turn off the CM1000. 

Any ideas are appreciated, and happy to provide more details. Thank you!

[antinode]

> Alright I will pose a question with some specifics.

   Why attach it to this months-old thread instead of starting your own
new thread for it?

> Cm1000 plugged directly into my Alienware R6 computer through ethernet
> cable. WIFI is turned off on the PC. Orbi rbk50 two pack mesh system.

   If the CM1000 is "plugged directly into [your] Alienware R6 computer
through ethernet cable", then where does the Orbi stuff come in?

> Modem and Orbi are talking correctly [...]

   How, if the CM1000 is "plugged directly into [your] Alienware R6
computer through ethernet cable"?

> Any ideas are appreciated, and happy to provide more details. [...]

   My suggestion would be to start a new thread, and in it, provide a
clear description of what is connected to what.  (Hint: If a device has
multiple Ethernet ports, then "connected to device" is not enough
detail.)

[SSJDUSTEN]

You seemed like a stickler for details, so figured I would start here. 

Taking the direct connection from my PC to the orbi. Using ethernet cable to go from modem to orbi mesh system. Now PC is connected from pc to orbi router. Orbi router has 3 available ports on the back. PC, Hue Bridge, and an empty one. 

Once I plug in the PS4 or the Xbox into the empty slot, the router just has the solid orange light as described. 

   (CM1000) ---> (ORBI)        PC     Hue Bridge   Ethernet connected to -----> ORBI      (PS4) ----> (Orbi) <--- Problem!