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Constant DNS error - Going insane please help

Last response: in Networking
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March 28, 2012 3:30:00 AM

Okay. I've been dealing with this for a few days. Anytime I am home I am trying to fix it. I would really appreciate any kind of help...going to try to sum this up.

I keep getting "DNS" errors when I try to get online. However! It happens only at a CERTAIN time of day. 6:30PM. I've already Done these things:

flushed my DNS,renewed it. Released my IP, renewed. Tried using Google's DNS servers.
Disconnected router - connected modem directly into PC.
BOUGHT NEW router.
Installed an upgraded motherboard.
Called my ISP (Comcast)
+Installed fresh copy of Windows 7 - same thing

I am going insane here! I know I'm not the only one with this problems. Been searching online anytime I do have access also - people have said they have this problems but there is no "Go to" fix.

I am running Windows 7 64bit. 8Gigs. What I notice: My modem (http://192.168.100.1/) says this

  1. Name
  2. DPC2100R2
  3.  
  4. Modem Serial Number
  5. 213719599
  6.  
  7. Cable Modem MAC Address
  8. 00:1c:ea:39:98:ac
  9.  
  10. Hardware Version
  11. 2.1
  12.  
  13. Software Version
  14. dpc2100R2-v2.0.2r1256-100817as
  15.  
  16. Receive Power Level
  17. -12.5 dBmV
  18.  
  19. Signal to Noise Ratio
  20. 35.4 dB
  21.  
  22. Transmit Power Level
  23. 54.0 dBmV
  24.  
  25. Cable Modem Status
  26. Operational


THIS is what it says when I have the DNS error:

  1. Name
  2. DPC2100R2
  3.  
  4. Modem Serial Number
  5. 213719599
  6.  
  7. Cable Modem MAC Address
  8. 00:1c:ea:39:98:ac
  9.  
  10. Hardware Version
  11. 2.1
  12.  
  13. Software Version
  14. dpc2100R2-v2.0.2r1256-100817as
  15.  
  16. Receive Power Level
  17. -12.8 dBmV
  18.  
  19. Signal to Noise Ratio
  20. 35.4 dB
  21.  
  22. Transmit Power Level
  23. 54.0 dBmV
  24.  
  25. Cable Modem Status
  26. Access Denied


Here is the ipconfig /all info which i've seen posted a few times that tends to help in some way.

WORKING (And Not working. Will double check when I get the DNS again to make sure I didn't copy+paste incorrectly):
  1. Microsoft Windows [Version 6.1.7601]
  2. Copyright (c) 2009 Microsoft Corporation. All rights reserved.
  3.  
  4. C:\Users\x>ipconfig /all
  5.  
  6. Windows IP Configuration
  7.  
  8. Host Name . . . . . . . . . . . . : x-PC
  9. Primary Dns Suffix . . . . . . . :
  10. Node Type . . . . . . . . . . . . : Hybrid
  11. IP Routing Enabled. . . . . . . . : No
  12. WINS Proxy Enabled. . . . . . . . : No
  13. DNS Suffix Search List. . . . . . : hsd1.fl.comcast.net.
  14.  
  15. Ethernet adapter Local Area Connection 3:
  16.  
  17. Connection-specific DNS Suffix . : hsd1.fl.comcast.net.
  18. Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
  19. Physical Address. . . . . . . . . : 1C-6F-65-D4-E3-46
  20. DHCP Enabled. . . . . . . . . . . : Yes
  21. Autoconfiguration Enabled . . . . : Yes
  22. Link-local IPv6 Address . . . . . : fe80::6009:394a:77e2:3984%16(Preferred)
  23. IPv4 Address. . . . . . . . . . . : 192.168.1.103(Preferred)
  24. Subnet Mask . . . . . . . . . . . : 255.255.255.0
  25. Lease Obtained. . . . . . . . . . : Tuesday, March 27, 2012 3:23:27 PM
  26. Lease Expires . . . . . . . . . . : Wednesday, March 28, 2012 3:23:27 PM
  27. Default Gateway . . . . . . . . . : 192.168.1.1
  28. DHCP Server . . . . . . . . . . . : 192.168.1.1
  29. DHCPv6 IAID . . . . . . . . . . . : 337407845
  30. DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-16-0B-E4-B4-00-22-15-58-F2-8E
  31.  
  32. DNS Servers . . . . . . . . . . . : 8.8.8.8
  33. 8.8.4.4
  34. 75.75.75.75
  35. NetBIOS over Tcpip. . . . . . . . : Enabled
  36.  
  37. Tunnel adapter isatap.{F589C30E-DC4D-4ACC-95A0-33D8039EC5BA}:
  38.  
  39. Media State . . . . . . . . . . . : Media disconnected
  40. Connection-specific DNS Suffix . : hsd1.fl.comcast.net.
  41. Description . . . . . . . . . . . : Microsoft ISATAP Adapter
  42. Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
  43. DHCP Enabled. . . . . . . . . . . : No
  44. Autoconfiguration Enabled . . . . : Yes
  45.  
  46. Tunnel adapter Teredo Tunneling Pseudo-Interface:
  47.  
  48. Connection-specific DNS Suffix . :
  49. Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
  50. Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
  51. DHCP Enabled. . . . . . . . . . . : No
  52. Autoconfiguration Enabled . . . . : Yes
  53. IPv6 Address. . . . . . . . . . . : 2001:0:4137:9e76:845:3aa2:3f57:fe98(Prefe
  54. rred)
  55. Link-local IPv6 Address . . . . . : fe80::845:3aa2:3f57:fe98%13(Preferred)
  56. Default Gateway . . . . . . . . . : ::
  57. NetBIOS over Tcpip. . . . . . . . : Disabled
  58.  
  59. C:\Users\x>


I thought I would "out cheat" the system. I set my time to 3PM and after a few resets on my router. It works. I am online. Every X minutes it dies and I am getting the DNS error - and I am told I am constantly re-logging on instant messaging services. However during the day the internet works FLAWLESSLY. Only around 6PM do I usually experience problems. I am stumped. I like to do things myself however this time..I just give in. Ready to just move to another house at this point!
March 28, 2012 12:46:54 PM

If the modem is denying you, it is your ISP's responsibility. Your cable modem loads it's configuration from a file that is sent from your ISP, comcast. You can have them try to swap the modem out, but I don't think it will help as I think it's a configuration problem on their end.
m
0
l
March 28, 2012 3:09:43 PM

Disable IPv6 and the Link Layer topologies on your network card.

All internet drops off when this happens? Try pinging a website prior to this happening and leaving it running: ping -t websitename

Then, when it happens, try pinging another website. Does the website resolve to an IP address like this: Pinging www.tomshardware.com [208.48.161.105] with 32 bytes of data:
Tom's is a bad example as pinging in blocked. But you get the idea, find a site you can ping.

How long does the issue last before being resolved? Could be a DoS on you, could be IPv6 doing some funky things.

m
0
l
July 5, 2012 1:44:18 AM

I had the same problem for more than TWO YEARS!

The issue turned out to be poor/weak signal strength between the modem and the gateway. The solution finally turned out to be: COMCAST replaced ALL of the cable between the modem and the pole. At the pole, they discovered a highly corroded coupling and replaced that with an appropriate jumper and new hardware. To give you an idea: The signal strength was -11db at the junction box on the house. The incoming line provides signal to both my Tivo box and the modem. I was experiencing declining connection times and speeds in the last several months until finally I could only connect about 30-60 seconds about every hour or two. Once the cabling was replaced, the signal strength jumped to 7db at the junction. Moreover, I removed the manually set DNS DHCP setting on my wireless router that was pointed at the Google DNS (208.67.222.222). With the new and improved signal strength, the modem was able to connect with and resolve the DNS server and the system started working again.

Moreover, I know the inside equipment was working perfectly because it worked perfectly when it worked. Hardware failures are rarely intermittent like I was experiencing. Additionally, I had replaced BOTH the modem and the wireless router to prove that they were not the failures.

It too TWO YEARS and numerous calls and getting called a liar and worse by COMCAST. I hate COMCAST. If I had any other choice than COMCAST, I would take it. They are a miserable company with only a few decent, thinking, thoughtful and intelligent people working for and with them -- at least on the customer facing side.
m
0
l
!