# DNS server isn't responding



## PhysicsNerd (Oct 23, 2012)

Alright, so here's my problem.
I can generally use just about any internet connection without issue. I can be online for hours at a time and never have to try to figure out why my internet is acting up; however, I am consistently running into this single issue with the modem I am using now: pages will randomly stop loading and I will find a warning symbol in my network panel. If I troubleshoot the problem, I will get the message "The DNS server isn't responding" and, if I click for more detail, "Your computer is trying to use a DNS server that is incorrect or doesn’t exist."

The modem I am using is a Clear Atlas, model PXU1960. In case my laptop brand is needed, too, I am using a Toshiba.

I have already checked Clear's files pertaining to an issue that some Windows 7 and Vista users experience, but the problem does not appear to be the same as the one described by their details. I can still get on the internet; it just stops working at random times.

Does anyone have any recommendations/solutions for this problem? I would like to be able to browse around without having to unplug my modem and plug it back in every once in a while.


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## Wand3r3r (Sep 17, 2010)

Welcome to TSF!

Lets start by you posting the results of a ipconfig /all for review.

I would also suggest you call your isp and have them to a line and modem check. Having to power cycle the modem indicates its failing.


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## PhysicsNerd (Oct 23, 2012)

Here are the results of the ipconfig/all:

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.

C:\Users\Owner>ipconfig/all

Windows IP Configuration

Host Name . . . . . . . . . . . . : Owner-PC
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : clearwire-wmx.net

Ethernet adapter Local Area Connection 2:

Connection-specific DNS Suffix . : clearwire-wmx.net
Description . . . . . . . . . . . : RNDIS
Physical Address. . . . . . . . . : 00-1D-88-81-5E-87
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::3ca9:8451:63d6:eaa5%16(Preferred)
IPv4 Address. . . . . . . . . . . : 71.20.49.92(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.192.0
Lease Obtained. . . . . . . . . . : Tuesday, October 23, 2012 3:02:25 PM
Lease Expires . . . . . . . . . . : Tuesday, October 23, 2012 3:03:55 PM
Default Gateway . . . . . . . . . : 71.20.0.1
DHCP Server . . . . . . . . . . . : 192.168.14.1
DHCPv6 IAID . . . . . . . . . . . : 419437960
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-16-67-F1-99-E0-CA-94-9B-A9-B5

DNS Servers . . . . . . . . . . . : 192.168.14.1
64.13.115.12
75.94.255.12
Primary WINS Server . . . . . . . : 192.168.14.1
NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Local Area Connection:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Atheros AR8152/8158 PCI-E Fast Ethernet C
ontroller (NDIS 6.20)
Physical Address. . . . . . . . . : 00-26-6C-E8-D4-07
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes

Wireless LAN adapter Wireless Network Connection:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Realtek RTL8188CE Wireless LAN 802.11n PC
I-E NIC
Physical Address. . . . . . . . . : E0-CA-94-9B-A9-B5
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter isatap.{4A3CFAF5-5175-4DBE-9CC8-321DA0F85534}:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft ISATAP Adapter
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter isatap.{0B44A563-A71F-4AC3-9EFE-A0DC0C947EDF}:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft ISATAP Adapter #2
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Teredo Tunneling Pseudo-Interface:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
IPv6 Address. . . . . . . . . . . : 2001:0:9d38:6ab8:cc1:3809:b8eb:cea3(Prefe
rred)
Link-local IPv6 Address . . . . . : fe80::cc1:3809:b8eb:cea3%13(Preferred)
Default Gateway . . . . . . . . . :
NetBIOS over Tcpip. . . . . . . . : Disabled

Tunnel adapter isatap.clearwire-wmx.net:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . : clearwire-wmx.net
Description . . . . . . . . . . . : Microsoft ISATAP Adapter #3
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter 6TO4 Adapter:

Connection-specific DNS Suffix . : clearwire-wmx.net
Description . . . . . . . . . . . : Microsoft 6to4 Adapter
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
IPv6 Address. . . . . . . . . . . : 2002:4714:315c::4714:315c(Preferred)
Default Gateway . . . . . . . . . : 2002:c058:6301::c058:6301
DNS Servers . . . . . . . . . . . : 192.168.14.1
64.13.115.12
75.94.255.12
NetBIOS over Tcpip. . . . . . . . : Disabled

C:\Users\Owner>


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## Wand3r3r (Sep 17, 2010)

These are some strange settings

IPv4 Address. . . . . . . . . . . : 71.20.49.92(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.192.0
Lease Obtained. . . . . . . . . . : Tuesday, October 23, 2012 3:02:25 PM
Lease Expires . . . . . . . . . . : Tuesday, October 23, 2012 3:03:55 PM
Default Gateway . . . . . . . . . : 71.20.0.1
DHCP Server . . . . . . . . . . . : 192.168.14.1
DHCPv6 IAID . . . . . . . . . . . : 419437960
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-16-67-F1-99-E0-CA-94-9B-A9-B5

DNS Servers . . . . . . . . . . . : 192.168.14.1 *<--- private ip and not a internet dns server* You don't point to dhcp server for dns but the gateway ip if there is no dns server.
64.13.115.12 *<--- invalid dns server*

These are simple to check with nslookup. You can see below only the last entry for dns is valid. Bad dns = no internet.

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.

C:\Users\>nslookup 64.13.115.12
Server: cdns01.comcast.net
Address: 75.75.75.75

*** cdns01.comcast.net can't find 64.13.115.12: Non-existent domain

C:\Users\>nslookup 75.94.255.12
Server: cdns01.comcast.net
Address: 75.75.75.75

Name: 75-94-255-12.gar.clearwire-wmx.net
Address: 75.94.255.12

If you can logon to this modem/router device you can make the corrections. If not you need the ISP to make these corrections so you get the correct ip information.

Only 75.94.255.12 for dns appears valid and its the last listed.


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## Network_Sage (Dec 7, 2014)

Wand3r3r said:


> These are some strange settings
> 
> IPv4 Address. . . . . . . . . . . : 71.20.49.92(Preferred)
> Subnet Mask . . . . . . . . . . . : 255.255.192.0
> ...


Actually, 64.13.115.12 is indeed a valid DNS server. There is nothing in the DNS spec that states a DNS resolver must have a valid PTR record (or any other type of record, for that matter). 

64.13.115.12 is responsive and answering queries, and is in fact one of the faster DNS servers for the Pacific Northwest.

Also, on the PXU1960, 192.168.14.1 is the IP address on the device itself which is running a DNS resolver, so this is also perfectly valid.


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## Wand3r3r (Sep 17, 2010)

Thanks for the comments.


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