CAX 80 & Xfinity Issues

Question

I have an older Netgear C7000-100NAS cable modem that I am getting 760 Mbps out of connected to Xfinity Gig internet that I just upgraded to. I wanted to upgrade the cable modem to get more of the speed I am paying for so chose the CAX80. The C7000 is about 6 years old now.

1st box had issues with no connection established which you will se below just read on.

2nd Box - this time pre-configure the router before connecting to Xfinity to see if I can actually connect to it.

Connect direct to iMac using 6 ft ethernet cable at my desk upstairs

Can connect to the gateway 192.168.1.1

Configure router to be 10.0.0.1 which my network wants

Configure WiFi to be single name 2.4 & 5.0 with my preferred name and password

Update firmware to V2.1.3.5 which is already stored on my iMac

Reboot router - can connect to 10.0.0.1

Did not check WiFi connection, probably should have

Take it downstairs and connect to incoming cable

Connect 1 ethernet cable that goes to 16 port switch and all upstairs equipment including my iMac

Connect 2nd ethernet cable that goes to 8 port switch near router for all downstairs equipment

Turn power on

Using Xfinity app on iPhone do new equipment activation, provide Mac and wait

All lights come on correctly, Xfinity App says it’s registered and online

Try to connect iPhone and iPad sitting ft from the router through WiFi

- All connection attempts refused

- Some attempts just hang with spinning wheel

- Some attempts say cannot connect

- Some attempts say incorrect password, provide password again to no avail

Come upstair to hardwired iMac through 16 port switch

- try to connect to 10.0.0.1 to no avail

This is exactly where I was with the first box I received, the only difference being I did not do the direct connect to my iMac and pre-setup before connecting to Xfinity so the gateway address was 192.168.1.1 which was unreachable direct connected. Gave up on the first box and sent it back.

Continue with 2nd box:

Disconnect router, bring back upstairs and connect direct to iMac again with 6 ft cable

Connect to 10.0.0.1 is fine, confirm that WiFi password is correct and the same one used in previous failed connection attempts, all looks good.

Bring back downstairs

This time, only connect the cable with no direct ethernet connections

Power on and wait

All lights on

Try to connect with iPhone and iPad and all is working

Do some speed tests and all looks good

Go upstairs and turn on WiFi on iMac

Can connect with iMac through WiFi and speed tests good

Go back downstairs and reconnect the 2 ethernet cables while the router is on

WiFi to iPhone and iPad still OK

Go upstairs and turn off WiFi on iMac and use ethernet cable through switch to router

All looks good - 952 Mbps to the iMac wired

Go back downstairs and reboot the router with the 2 ethernet connections attached

Same situation as before, nothing will now connect to the router

Giving up and sending the 2nd unit back.

FURRYe38 · Answer

So I would have done a factory reset with the CAX80 and setup from scratch and this time, do NOT change the LAN configuration to 10.0.0.1. Leave the IP address at default 192.168.1.1 and with 1 wired PC, connect the CAX80 and ensure the CAX80 is connected to the coax ISP line and don't connect any other devices to the back of the CAX80, just 1 wired PC or laptop. After the CAX80 is setup using default LAN IP address, check to see if the wired PC or laptop gets an IP address fron the modem. Should get a 192.168.1.something address. Also check it's web page on the Basic Tab to see if the Internet section tile reports a GOOD status.&nbsp;
Check internet access thru the wired PC only.&nbsp;
&nbsp;
Can you get to this point in the configuration and setup on the CAX80?&nbsp;

davidbod · Answer

I am wiling to be the gunea pig and try and solve what is going on. I had done this with the first box I received, but it was still going through the TP-Link 16 port switch. So I have a very new Windows laptop that I can try this with to completely isolate my Lan from the situation. I'll do some tests with my C7000 to get a baseline, then setup the CAX80 as you suggest, both modem routers with just cable and 1 ethernet to the laptop connected. If there are other firmware version to try I'm willing to do that to and report findings.

I'll be out for a couple hours, then I can start with the above tests.

FURRYe38 · Answer

What is the model of the TP Link Switch? This a managed switch or un-managed?&nbsp;
I also have switches behing my CAX80 however have never encountered problems with the CAX and my switches...my switches are all unmanaged. HP and Netgear.

davidbod · Answer

So this has been my setup for the last 6 years:

C7000-100NAS Cable Modem / Router / WiFi but WiFi radio turned off

Wired Ethernet Connections:

1 - R7000 WiFi only (no router) installed on 3rd floor upstairs

2 - EX8000 2nd Wifi name installed downstairs on 1st floor

3 - TP-Link (TL-SG2008) managed switch 1st floor at TV

4 - TP-Link (TL-SG2216) managed switch 2nd floor at TV

TP-Link (TL-SG2008)

1 - To Router

2 - TV

3 - Apple TV

4 - Sonos Sound-Bar

TP-Link (TL-SG2216)

1- To Router

2- TV

3- Xbox

4- Sonos Connect

5- Sonos Amp

6- Sonos Amp

7- Synology NAS

8- iMac

9- iMac

10- Printer

This is what I tested this afternoon:

The laptop is so new it doesn’t have an ethernet port so tests using one of the iMacs downstairs

In the next 2 tests the iMac is the only thing connected to the routers

C7000 —Wired—> iMac

783.4, 759.8, 771.7 Mbps

CAX80 Factory Reset 192.168.1.1 Gateway address

CAX80 —Wired—> iMac

917.4, 920.2, 926.0 Mbps

In the Wi-Fi connection tests below when I am using the CAX80 Wi-Fi because it has a new to my network name and password, only the devices being tested are connected and the EX8000 is unplugged. When I am using the EX8000, the radio on the C7000 or CAX80 is turned off, but since this is my regular network, many other devices are connected, but not really providing traffic. Neither router has any other ethernet connections during the tests, only the EX8000 if being used.

My standard setup

C7000-100NAS —Wired—> EX8000 —Wi-Fi—> iMac about 2ft distance

The Wi-Fi radio on the C7000 is turned off and the EX8000 uses smart connect

585.3, 584.3, 573.5 Mbps

Change Modem Router

CAX80 —Wi-Fi—> iMac about 2ft distance

29.1, 84.9, 75.5 Mbps

Let’s change to smart connect as that is really bad

Enable smart connect on CAX80

iMac 3 ft

799.9, 827.8, 721.1 Mbps

Same as above

iPhone 13 Pro Max about 15 ft distance

430.9, 438.6, 398.3 Mbps

It all looks good to this point

Turn off Wi-Fi Radio on CAX80

Connect EX8000 - the only thing connected

iMac about 15 ft distance

605.3, 680.9, 693.7

iPhone 13 Pro Max about 15 ft distance

578.3, 577.4, 573.6

So maybe the EX8000 has better Wi-Fi

Reboot CAX80 with Wi-Fi off EX8000 connected

All came back ok

Unplug EX8000

CAX80 turn Wi-Fi radio back on and reboot with only cable connection

iPhone connected ok

iMac didn’t connect even with manual DHCP renew attempts

Reboot iMac now have an address and connection

Now make Ethernet connections

Connect downstairs TP-Link (TL-SG2008) 8 port switch

Seems ok

Reboot CAX80

iMac took several minutes to re-establish connection

Otherwise seems ok

Connect TP-Link (TL-SG2216) 16-port switch

iPhone and iMac Wi-Fi connected still ok

This killed the connection to the 8-port switch

Spotify running on Apple TV to Sonos no connection

And 2nd iMac upstairs on 16-port will not connect to the internet even after rebooting the iMac

Reboot CAX80

Downstairs iMac didn’t reconnect even with manual refresh DHCP

Reboot iMac no luck

Reboot iMac finally back after some initial flaky connections

Spotify Sonos not connected through Apple TV

Upstairs iMac has an IP address and can be refreshed, but never connects to the internet

Connect old C7000 to cable, connect 16-port switch, 8-port switch, EX8000, and direct connect iMac so all 4 Ethernet ports occupied, turn it on.

Downstairs iMac direct wired is getting

772.0, 780.3, 766.4

Downstairs iMac through Wi-Fi to EX8000

551.0, 562.6, 579.3

Apple TV Spotify Sonos is working

iPhone 13 Pro Max

484.7, 502.0, 506.0

Upstairs iMac through 16-port switch

768.6, 752.6, 763.5

Both iMacs back upstairs direct connected to 16-port switch and simultaneous tests

iMac 1: 496.8, 374.2, 486.3

iMac 2: 327.1, 421.2, 272.5

At this point I think the CAX80 has hardware issues. It seems to be ok until you load it up, and then it craters. It's possible it doesn't like my switches, but these have been working fine for 6 years and are still working fine connected to the C7000.

schmidt545 · Answer

I am wondering if I can tie my cax 80 to the ethernet port on the tv cable box?

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CAX 80 & Xfinity Issues

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