Netgear CM400 and AirPort Express, no internet. Ipv6 ok, no Ipv4 - help!

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Level 1

4 points

Netgear CM400 and AirPort Express, no internet. Ipv6 ok, no Ipv4 - help!

Hello all,

I have just purchased and setup the Netgear CM400 modem and am attaching it to my Airport Express (gen2) station. The Airport has worked tirelessly before without any hiccups!

Latest firmware on the Airport and brand new CM400 modem.

Internet is easily accessible with a direct connection of laptop to modem. Once i Introduce the Airport Express unit, all is green lit via Airport utility, except my laptop is no longer seeing ipv4 DNS servers (or so I think). I can access sites like Google and FB, which seem to be ipv6. Nothing else, that is ordinary, like CNN or Weather Channel for example, goes through. There are odd moments, just as modem comes online with a good IP that the router channels full internet no issue, but for a split second. Airport always shows good IP and what seems to be correct DNS (in gray text, in the field where you could manually enter DNS)

Wired, Wireless, makes no difference. Restarted in countless configurations, called comcast to re-initialize modem and etc. Nothing has worked so far and hence my turning to the community.

Any ideas? suggestions? I do not know if its the Airport, or something to do with the modem. I have not been able to find much chatter on the web about any similar issues.

Thank you for your time!

MacBook Pro (Retina, Mid 2012), iOS 8.3

Posted on Apr 28, 2015 9:50 PM

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Answer 1

Apr 29, 2015 3:34 AM in response to dmitriyo

The Express should be setup in DHCP on the Internet tab.. and it should be DHCP and NAT on the network tab.. plus create a wireless network.

Is this the setup you have.

Try turning off the modem overnight and power up next morning.. you can leave the express turned on.. no luck then I would suggest it is just unsuitable..

The Express is not really designed as the main router of a network.. it is for wireless extend and airplay to speakers etc.

If you like post the screenshot of the summary page once you follow the above so I can see both the summary page and the internet tab.

Click edit and then click the other tabs to pick up the Internet and network tabs.

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Answer 2

dmitriyo Author

Level 1

4 points

Apr 29, 2015 10:08 AM in response to LaPastenague

Thank you for the reply

The Airport Ex is in the correct mode of DHCP and NAT, and Ive power cycled the devices along with the overnight modem powerdown in hopes the it could clear the device association. All to no avail

I will re-set itup tonight and send a screenshot - it does look like what you have though- All green lit. Again, full internet appears for a split second, then IPV4 stuff is inaccessible, even through the Airport shows all is good. IPV6 sites like google load great, just cant click past the search results.

Thank you again. I see others putting in Google or other DNS values.. or playing with how Ipv6 stuff (automatic/native/locallink) and Ive tried some options, but not to the full extent as the basics dont even work (ipv4)

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Answer 3

dmitriyo Author

Level 1

4 points

Apr 29, 2015 6:19 PM in response to dmitriyo

Brought in the Airport Express to work to test the functionality again. Hooked up and no issues - didn't even have to touch the settings.

With current information - it seems the airport express is simply, somehow, incompatible with he CM400 Netgear Router (bought Apr 28, 2015).

I will be considering switching to the Surfboard SB6141 modem, as its been considered the workhorse of cable internet it seems.

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Answer 4

Apr 29, 2015 6:57 PM in response to dmitriyo

I will be considering switching to the Surfboard SB6141 modem, as its been considered the workhorse of cable internet it seems.

Worse and worse..

The SB series is an issue.. frankly I do not know the reason.. and I have no access.. living in Australia we don't use them.

But from what I hear in the US.. Ubee or Zoom seem to work ok.

I have no idea if those models work well with your service.. you will need to look them up.

Some people have found a crossover cable fixes the problems.. and sometimes a small 10/100 switch will work.. but I can also tell you some also find those work arounds fail.

I do believe you would do better with a different brand router..

eg TP-Link WR1043ND.. should only be around $50 in the US... you can flash this with gargoyle firmware.. and keep using the airport in bridge.

WNDR3800 is what I am running now.. since I have a least a dozen airports here.. (I repair them).. and not a one works on my bridged adsl system.. !! Apple need to fix the PPPOE client or give us some more controls. So in some cases there is simply no choice but to give up the apple as router.. I still run it in static IP mode.. and it works great for what i need.

https://discussions.apple.com/thread/5981989?answerId=25135547022#25135547022&ac_cid=tw123456#

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Answer 5

John Galt

Level 10

141,132 points

Apr 29, 2015 8:33 PM in response to dmitriyo

There have been problems reported on this site specifically with the Motorola SB6141 modem. I have not been able to confirm them.

Other Motorola modems such as the SB5100 series work perfectly OK.

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Answer 6

dmitriyo Author

Level 1

4 points

Apr 29, 2015 10:27 PM in response to John Galt

Ah thats re-assuring. THank you for the heads-up.

Reposting the same in the Netgear forums and talking to Netgear support - maybe will get somewhere. (doubtful)

Any ideas are welcome. - just one step away from swapping out the modem for another unit.

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Answer 7

dmitriyo Author

Level 1

4 points

Apr 29, 2015 11:24 PM in response to dmitriyo

Did some ping tests

//pinging when all is connected: modem to airport ex to laptop via wifi. I can browse to google.com (ipv6) no problem even though it does not ping. Also pinged www.cnn.com

Ping has started…

PING turner.map.fastly.net (23.235.47.73): 56 data bytes

Request timeout for icmp_seq 0

Request timeout for icmp_seq 1

Request timeout for icmp_seq 2

--- turner.map.fastly.net ping statistics ---

4 packets transmitted, 0 packets received, 100.0% packet loss

Ping has started…

PING www.google.com (74.125.196.104): 56 data bytes

Request timeout for icmp_seq 0

Request timeout for icmp_seq 1

Request timeout for icmp_seq 2

--- www.google.com ping statistics ---

4 packets transmitted, 0 packets received, 100.0% packet loss

//pinging as soon as router reconnects to laptop. I started pinging before the computer re-connected to airport via wifi. as you can see it picks up connections for a second, and then cuts out.

Ping has started…

PING www.google.com (216.58.216.36): 56 data bytes

Request timeout for icmp_seq 0

Request timeout for icmp_seq 1

Request timeout for icmp_seq 2

Request timeout for icmp_seq 3

64 bytes from 216.58.216.36: icmp_seq=4 ttl=51 time=22.150 ms

Request timeout for icmp_seq 5

Request timeout for icmp_seq 6

Request timeout for icmp_seq 7

Request timeout for icmp_seq 8

64 bytes from 216.58.216.36: icmp_seq=9 ttl=51 time=31.679 ms

64 bytes from 216.58.216.36: icmp_seq=10 ttl=51 time=22.251 ms

64 bytes from 216.58.216.36: icmp_seq=11 ttl=51 time=23.300 ms

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Answer 8

dmitriyo Author

Level 1

4 points

May 3, 2015 8:16 PM in response to dmitriyo

Update:

Got a new modem - Motorolla SB 6141. That exact model has worked with the airport express at the neighbors so all should've worked just great.

It did not - same issue with the new modem. In a parallel setup at another home - all works great.

The one thing that I wonder about: I set up the modem directly connected to a computer, to initially get it registered to the comcast network (neighbors already have theirs hooked up).

I wonder if there is a need to specifically have the modem hooked up to the router at setup - if something registers in some other way.

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Answer 9

May 3, 2015 8:32 PM in response to dmitriyo

The one thing that I wonder about: I set up the modem directly connected to a computer, to initially get it registered to the comcast network (neighbors already have theirs hooked up).

If you did this, the modem is married to your computer, and it will totally ignore the AirPort router.

You need for the modem to divorce the computer, so that it will hopefully become interested in the AirPort router. To do that, power off the modem completely. That means pulling the power cord from the back of the modem, or pulling the power cord from the AC wall jack.

Leave the modem powered off for at least 30 minutes. Longer would be better.

Power off the AirPort router as well.

After the modem power down period, make sure that the Ethernet cable connects to the WAN O port on the AirPort

Power up the modem, and let it run for at least 10 minutes by itself.

Then, power up the AirPort and let it run for a few minutes.

If the modem divorced your computer and became interested in your AirPort, you will have an Internet connection on all of your devices.

If it didn't, you will need to start over again and power down the modem for a longer period. Overnight would be good.

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