CGN3 - LAN works fine. No DNS on WiFi devices and no packets flow wifi<->LAN

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I'm Here A Lot
Posts: 5

CGN3 - LAN works fine. No DNS on WiFi devices and no packets flow wifi<->LAN

I have a new CGN3 type Hitron modem installed.
This is a trivial network config for LAN direct attached devices and WiFi.
All LAN attached devices have new CAT6 cables and they work fine. 
I have a WiFi config that uses DHCP to allocate ips out to devices and they connect fine.
DNS does not work for any WiFi attached device. 
A WiFi attached device ( laptop or cell phone ) can not ping any other device.
A WiFi attached device can not ping any LAN attached device.
A LAN attached device can not ping any WiFi device.
A LAN attached device CAN ping any other LAN attached device.

They mystery here is why there is not a single packet flowing from WiFi 
out to the world and also why no WiFi attached device has DNS services. 

Probably something trivial. 

A bit of data the internal subnet is 172.16.35.0/26 which means we have 172.16.35.1 for the CGN3 Hitron modem .
All other dvices are in the range up to 172.16.35.62.  The broadcast address is 172.16.35.63.
There exists a DHCP range from 172.16.35.16 up to 172.16.35.31.
There are no ip conflicts because all LAN attached devices are static and there are only two of them.
One machine is at 172.16.35.41 and the other at 172.16.35.9.


 *Edited Labels*

Solved! Go to Solution.
Resident Expert
Resident Expert
Posts: 6,020

Re: CGN3 - LAN works fine. No DNS on WiFi devices and no packets flow wifi<->LAN

Try this on a wifi laptop.  Bring up a command prompt and type:

 

ipconfig/release

inconfig/flushdns

ipconfig/renew

inconfig/all

 

The last command will show the LAN parameters for the laptop.  The DNS address is found in the 2nd data group, shown as "DNS Servers".  Compare those addresses to one of your wired pc's.  They should be the same.  If they aren't, you will have to drill down into the laptop IPV4 settings to ensure the laptop is set for Auto DNS selection.

 

There is another post in here somewhere posted within the last week or so with a similar problem, just can't seen to find it at the moment.  

 

To change the modem's DNS address, if you haven't done so already, log into the modem, navigate to BASIC.... DNS tab or page, change the LAN DNS Obtain to Manual, and enter the DNS 1 and 2 addresses, save the data and reboot the modem.  Navigate to ADMIN.... DEVICE RESET to reboot the modem by using the reboot function. 

 

Try Google's DNS 8.8.8.8 and 8.8.4.4 or OpenDNS 208.67.222.222 and 208.67.220.220



I'm Here A Lot
Posts: 5

Re: CGN3 - LAN works fine. No DNS on WiFi devices and no packets flow wifi<->LAN

Thank you.

Yes, I already checked the DNS setting on the LapTop and it is as it should be pointing to
the three corporate DNS servers at the office and the datacenter. Those DNS servers all
have granted permissions to this ROGERS subnet for both query and recursion upwards to
other DNS servers. 

I checked the DNS servers logs and if I issue a "nslookup foo.com" then the server shows 
the query accepted and the LapTop receives the address fine. For any host or site foo
which doesn't matter really. 

Sp what I am saying is that DNS queries on the laptop actually do work and they do go
out to the DNS servers.  Certainly the primary DNS server. 

Also, I don't run windows other than inside virtual machines. 

However I do have a Vista machine I have to support.  

Let me check my new CGN3 router settings here a bit and gather more info.

funny how we don't see things until another person is looking

So now I see that I have devices allowed to connect to the new CGN3 router in a
list of allowed devices with the MAC addresses in there. I need to double check
that and be sure that the MAC addresses are correct.  :-\
Resident Expert
Resident Expert
Posts: 6,020

Re: CGN3 - LAN works fine. No DNS on WiFi devices and no packets flow wifi<->LAN

If you still have issues with the wifi side of the house, consider the fact that the Hitron modems are not the greatest in terms of wifi performance. That's standard, or so it would seem with all in one modem / router combos.  So, thats part of the puzzle, the wifi performance or lack thereof, of the modem.  The next is the wifi environment and wifi devices.

 

 

Here is some food for thought. Load inSSIDer on your laptop, which is a wifi monitoring application. When loaded on a dual band laptop, inSSIDer will monitor both 2.4 and 5 Ghz networks that can be detected by your laptop. Have a look to see what you're competing with in both bands. In a suburban area, the 2.4 Ghz band is usually pretty crowded and tough to work in, so, I'm not surprised that you're having problems. Usually the 5 Ghz band is less crowded and easier to find a clear channel. After you have a look at the display, you might be able to determine if there is any 2.4 Ghz channel that is clear enough that it might work with the present modem. Never know unless you have a look, using something such as inSSIDer. The program link below is for the last freebie version. A new version is out now that will handle 802.11ac networks in the 5 Ghz band, and which will work on a 802.11n laptop. The new version will read the broadcast management frames and display the 802.11ac networks that are running in the 5 Ghz band. Its worth the $20 U.S. to buy, so that you can see all of the networks that are nearby.

 

http://www.techspot.com/downloads/5936-inssider.html

 

What you want to see on the graphical display is that your network is the highest network shown, which indicates that it has the highest received power of all the received networks. Generally you want somewhere in the neighborhood of 40 to 45 dBmW separation between your network and any other network that is on the same or overlapping channel. So, while your network should be the tallest on the display, everthing else should be well below yours. When that power level separation decreases, you end up with interference and possibly with problems maintaining a wifi network. Your only option is to change to a channel with less overlap from the competition. By looking at that display you might conclude that the 2.4 Ghz band is hopeless and that its time to move up to the 5 Ghz band, if you can. If you have devices already running in the 5 Ghz band, look at channels 149 and higher. If you can switch to any of those channels, do so, as the output power for those channels is higher, resulting in better signal levels, signal to noise ratios and data rates.

 

Fwiw, the Hitron modem does not support beamforming, which is part of the 802.11ac spec. That allows the modem/router to aim a focused signal towards the laptop/device, etc, etc. The result is better signal levels, signal to noise ratios and data rates at the device. The RT-AC68U as an example, now replaced by the RT-AC68P supports implicit and explicit beamforming, meaning that the router can determine on its own where the device is and focus a directed wavefront in the devices direction (implicit), or, in conjunction with the device, direct a focused wavefront toward the device (explicit). Here's a link that provides some explanation:

 

http://www.pcworld.com/article/2061907/all-about-beamforming-the-faster-wi-fi-you-didnt-know-you-nee...

 

The other part of this is the actual device itself, or, more importantly, the wifi card. We've run into far too many examples of new, really nice laptops that are well thought out except for the cheap wifi card that was included. End result, much disappointment at the wifi performance. The way to determine that, for a laptop, is to drill down into the Device Manager, grab the wifi adapter model name and number from the Device Manager display and run a search for the manufacturers data. A 1x1 listed somewhere in the data means the laptop uses a single antenna for transmit and receive which will limit your data rates. A 2x2 meaning 2 antenna is normal but not guaranteed. This or better yet, 3x3 will provide better data rates. If you run a search you will also come across posts regarding difficulties that other users might be running into with that card, so it may give you a better idea of what you can do to improve the wifi performance.

 



I'm Here A Lot
Posts: 5

Re: CGN3 - LAN works fine. No DNS on WiFi devices and no packets flow wifi<->LAN

Awesome reply. Mostly I think I will need to use a LAN ( CAT6 ) for the laptop and I can live with that.
What I can not live with is that my new Samsung Galaxy S5 cell phone can not browse or do much of 
anything here at home when connected via wifi. I checked with a few different tools ( built into Linux )
and there are a pile of SSID's here in this area. No surprise. 

I will re-read your post in detail and give some thought to what is happening here. Could be nothing
more than blunt force interference. Hard to say but I'll figure it out. 

Lucky for me I have the 30G data plan for my cell phones so I really am not worried much about not
being on WiFi.  Yet. 

Resident Expert
Resident Expert
Posts: 6,020

Re: CGN3 - LAN works fine. No DNS on WiFi devices and no packets flow wifi<->LAN

Good luck figuring it out.  Hopefully there is a simple explanation and easy fix.  Are you using the Hitron for wifi, or using another router as an access point for wifi?



I've Been Here Awhile
Posts: 2

Re: CGN3 - LAN works fine. No DNS on WiFi devices and no packets flow wifi<->LAN

I change the DNS but when I save it. I keep getting a '

[ERROR]

Please input the DNS infomation !'

Is this happening to anyone else? Any suggestions?

thanks

Retired Moderator RogersPrasana
Retired Moderator
Posts: 624

Re: CGN3 - LAN works fine. No DNS on WiFi devices and no packets flow wifi<->LAN

Hi @juans587

 

Welcome to the Community Forums! 

 

That's definitely inconvenient to have to deal with. Have you tried factory resetting your modem? 

 

If you can try changing the DNS after a reset of your modem and let us know how that works out for you.

 

RogersPrasana 

 

 

I've Been Here Awhile
Posts: 2

Re: CGN3 - LAN works fine. No DNS on WiFi devices and no packets flow wifi<->LAN

Hi,

 

thank you for the info. I tried that and it worked. Not sure why I did not think of that myself but it works now.