Comcast XFINITY → [DNS] Comcast and Remote Desktop Issues

I have a Cable modem (with Comcast), wired/wireless router (D-Link DIR-655), and 4 Windows 7 machines (2 wired and 2 wireless).

My routers IP address is 10.0.5.1. It is running DHCP and handing out IP addresses in the range of 10.0.5.120 to 10.0.5.150.

I have reserved the IP addresses from my wired machines, my wired printer and my wired NAS server.

When I IP config any of my machines, I get the following which is correct:

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . : hsd1.fl.comcast.net.
Link-local IPv6 Address . . . . . : fe80::3025:4a4d:c4ce:1ead%11
IPv4 Address. . . . . . . . . . . : 10.0.5.120
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 10.0.5.1

Now, when I ping any other client on the network, I get this:

C:\Users\emiliob>ping cb_desktop

Pinging cb_desktop.hsd1.fl.comcast.net [208.67.216.145] with 32 bytes of data:
Reply from 208.67.216.145: bytes=32 time=100ms TTL=47
Reply from 208.67.216.145: bytes=32 time=101ms TTL=47
Reply from 208.67.216.145: bytes=32 time=99ms TTL=47
Reply from 208.67.216.145: bytes=32 time=101ms TTL=47

Ping statistics for 208.67.216.145:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 99ms, Maximum = 101ms, Average = 100ms

Why the HELL do I get a 208.67.216.145 address for a machine whose IPCONFIG show the LAN address to be 10.0.5.150??????????????? This is what is stopping me from RDP'ing within my little crap network and I cant figure it out. It is driving me INSANE!!!!!!!!!!!!!!!!!!!!!

I didn’t have this issue with AT&T (crap) DSL.

From what I have read is that cable companies don’t want you to share the internet connections among several machines. I don’t know how accurate that is or if its even true, but I refuse to believe there isn’t someone in the internet world that has had the same issue and found a workaround….

I have tried cloning my machines MAC address on the router so that it thinks that is the only machine but no go…

I am at a loss here….

More than likely the 10. IPs you picked are being used with in Comcast's network (very common among cable ISPs for modem management) and your router is passing traffic out the WAN port when pinging.

Try tracert and I'm sure you'll see this.

Block RFC1918 traffic from crossing the WAN port of your LAN. It's not needed.

This is what i get:

C:\Users\emiliob>tracert cb_desktop

Tracing route to cb_desktop.hsd1.fl.comcast.net [208.67.216.145]
over a maximum of 30 hops:

1 * * * Request timed out.
2 * * * Request timed out.
3 * * * Request timed out.
4 * * * Request timed out.
5 * * * Request timed out.
6......................................................................

Actually hold on.... I'm wrong about the RFC1918... it's not even going that way.

But, why is your desktop appending the full domain name to the target name? This shouldn't even be leaving your network and shouldn't need the full name.

That didnt seem to work. i changed the router IP to 192.168.1.1 and it handed out Ip addressed of 192.168.1.120 to 150. Still same results:

C:\Users\emiliob>ipconfig

Windows IP Configuration

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . : hsd1.fl.comcast.net.
Link-local IPv6 Address . . . . . : fe80::3025:4a4d:c4ce:1ead%11
IPv4 Address. . . . . . . . . . . : 192.168.1.120
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.1.1

Tunnel adapter isatap.hsd1.fl.comcast.net.:

Connection-specific DNS Suffix . : hsd1.fl.comcast.net.
Link-local IPv6 Address . . . . . : fe80::5efe:192.168.1.120%12
Default Gateway . . . . . . . . . :

Tunnel adapter Local Area Connection* 9:

Connection-specific DNS Suffix . :
IPv6 Address. . . . . . . . . . . : 2001:0:4137:9e76:1419:4cb:bedd:9cb
Link-local IPv6 Address . . . . . : fe80::1419:4cb:bedd:9cb%13
Default Gateway . . . . . . . . . : ::

C:\Users\emiliob>ping cb_desktop

Pinging cb_desktop.hsd1.fl.comcast.net [208.67.216.145] with 32 bytes of data:
Reply from 208.67.216.145: bytes=32 time=100ms TTL=47
Reply from 208.67.216.145: bytes=32 time=100ms TTL=47
Reply from 208.67.216.145: bytes=32 time=100ms TTL=47
Reply from 208.67.216.145: bytes=32 time=100ms TTL=47

Ping statistics for 208.67.216.145:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 100ms, Maximum = 100ms, Average = 100ms

Aha... You see why I am going insane... I dont get it!

Is your router doing DNS caching?

Not sure how to tell if its caching. But I would like to know how to clear its cache (which i havent figured out).

What does your PC show for DNS servers if you do an ipconfig/all ?

It kind of looks like you are using OpenDNS (or some third party DNS servers) in your router / pc and it's trying to do a lookup on the hostname from the web.

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . : hsd1.fl.comcast.net.
Description . . . . . . . . . . . : Realtek RTL8168B/8111B Family PCI-E Gigab
it Ethernet NIC (NDIS 6.20)
Physical Address. . . . . . . . . : (removed)
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::751b:37d5:f1f9:9f85%11(Preferred)
IPv4 Address. . . . . . . . . . . : 10.0.5.120(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : Sunday, November 28, 2010 6:44:09 PM
Lease Expires . . . . . . . . . . : Thursday, January 05, 2147 1:13:30 AM
Default Gateway . . . . . . . . . : 10.0.5.1
DHCP Server . . . . . . . . . . . : 10.0.5.1
DHCPv6 IAID . . . . . . . . . . . : 184556946
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-13-B6-91-18-00-1D-92-71-9B-DA

DNS Servers . . . . . . . . . . . : 10.0.5.1
NetBIOS over Tcpip. . . . . . . . : Enabled

Why not? Consider my 'ipconfig -all' result:

C:\Program Files (x86)\utils\ns_bench>ipconfig /all
 
Windows IP Configuration
 
   Host Name . . . . . . . . . . . . : Kozue
   Primary Dns Suffix  . . . . . . . :
   Node Type . . . . . . . . . . . . : Broadcast
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No
   DNS Suffix Search List. . . . . . : aosake.net
 
Ethernet adapter Local Area Connection:
 
   Connection-specific DNS Suffix  . : aosake.net
   Description . . . . . . . . . . . : Intel(R) PRO/100 VE Network Connection
   Physical Address. . . . . . . . . : 00-17-31-C6-CC-63
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::91d8:c501:13c8:3369%11(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.102.34(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : Friday, November 26, 2010 17:08:05
   Lease Expires . . . . . . . . . . : Tuesday, January 03, 2147 19:48:28
   Default Gateway . . . . . . . . . : 192.168.102.1
   DHCP Server . . . . . . . . . . . : 192.168.102.1
   DHCPv6 IAID . . . . . . . . . . . : 234886961
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-12-8E-B4-DC-00-17-31-C6-CC-63
 
   DNS Servers . . . . . . . . . . . : 68.94.156.1
                                       68.94.157.1
   NetBIOS over Tcpip. . . . . . . . : Enabled
 

Now consider a 'ping' command:

C:\Program Files (x86)\utils\ns_bench>ping kozue
 
Pinging kozue.aosake.net [192.168.102.34] with 32 bytes of data:
Reply from 192.168.102.34: bytes=32 time<1ms TTL=128
Reply from 192.168.102.34: bytes=32 time<1ms TTL=128
Reply from 192.168.102.34: bytes=32 time<1ms TTL=128
Reply from 192.168.102.34: bytes=32 time<1ms TTL=128
 
Ping statistics for 192.168.102.34:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 0ms, Average = 0ms
 

The D-Link DIR-655, which I am also using, has an optional entry for "Local Domain Name". In my router, I have set my domain as, 'aosake.net', and it gets appended to the host name I ping. Not sure if this is an artifact of the router, or my 'hosts' file entries. But it is normal where a "Local Domain Name" is configured in the D-Link DIR-655 router.

You have configured the OpenDNS servers in your router, yes? 208.67.222.222 and 208.67.220.220? You have also configured your router to use "DNS Relay", yes? So your DNS server IP address shows up as, 10.0.5.1 (when you configure your LAN IP address as 10.0.0.0/24), or as 192.168.1.1 (when you configure your LAN IP address as 192.168.1.1/24). Suggestions:

• Don't use OpenDNS, use the Comcast DNS servers instead.
• Turn off DNS Relay in your router.
• Don't worry about the results you are seeing.

The last option is in the case that you prefer to keep using OpenDNS. What you are seeing is just an artifact of the way your computer, and router, are interacting with each other, and your chosen DNS servers.


The DNS Relay option in the router.

This is exactly what I was typing. So I will just echo this!

NormanS hit the nail on the HEAD!

Actually if you type the IP issued into your browser »208.67.216.145 you'll find it's a Dlink DNS redirect search page.

If you follow the FAQ at the bottom of the page, you'll get this:
»www.dlink.com/support/fa ··· _id=3370

Apparently it's related to this:
»www.thebuzzmedia.com/d-l ··· our-dns/

Yep. This was it! I disabled the Advanced DNS Service. Set the Comcast DNS servers manually according to »www.whatsmydns.net/dns/u ··· ast.html and disabled DNS RELAY and VIOLA!!! Thank you so much! If you would have charged me for this i probably would have paid too since this has been the pain in my side for the weekend.

Maybe, maybe not. I have the 1.21 firmware, but I used the firmware without the "Securespot" bs. OTOH, one of the links on your first linked page clearly identifies 208.67.126/21 as belonging to OpenDNS, which also performs DNS redirects.

I stand by my original suggestions. Supposedly, the most recent version of the DIR-655 firmware eliminates problems with the DNS Relay option; but I don't know if one can opt out of the Securespot bs.

BTW, the issue raised in your second link, to the D-Link FAQ, is easily mitigated by creating a proper 'hosts' file, which names your local hosts, and aliases them to your local network IP addresses.

My suggestion would be to check out this link:

»[DNS] Comcast launches DNSSEC trial

Comcast is moving their users to these DNS servers:

75.75.75.75
75.75.76.76

This was it! I disabled the Advanced DNS Service. Set the Comcast DNS servers manually according to »www.whatsmydns.net/dns/u ··· ast.html and disabled DNS RELAY and VIOLA!!! Thank you so much! If you would have charged me for this i probably would have paid too since this has been the pain in my side for the weekend.

Thanks again! Just switched to this as well.

I think someone else suggested the same thing earlier, minus how to change it. lol

I am using the DNS provided by Dlink router when Advanced DNS service is checked. This does default to OpenDNS.

My router has firmware 1.34NA (not sure if it makes a difference).

If i disable DNS Relay, I lose internet connectivity on all machines.



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The firmware version probably makes a difference in regards to the options available. I had the 1.21 firmware when I first checked my rig. I don't recall whether "Enable Advanced DNS Service" was an option, or not. But I know I didn't use it if it was.

I just upgraded my firmware to 1.34NA. Out of curiosity, I enabled the "Advanced DNS Service". The DNS servers showing on my router status page are the DynDNS DNS servers (204.194.232.200 and 204.194.234.200).

Interesting. If "Enable Advanced DNS Service" is checked, disabling "DNS Relay" is not allowed!

Supposedly, this firmware release fixed a problem with "DNS Relay". So I disabled the "Advanced DNS Service", restored my ISP (ATTIS) DNS servers, then disabled "DNS Relay". This has not disabled my Internet connection. So I don't know how to explain what you have seen. You say you got the OpenDNS DNS servers with the 1.34NA firmware, but I get the DynDNS DNS servers. Do you have an OpenDNS account? I have a DynDNS account; though I don't know how the router should know that. However, with my DIR-655 at hardware version A2, and (now) firmware version 1.34NA, and configured as it was with firmware version 1.21; i.e., no "Advanced DNS Service", no "Securespot services" (not available in the 1.21 firmware I installed, disabled in the 1.34NA firmware), everything works just fine, and as expected.

Addendum: Damned firmware changes. First, the version 1.21 configuration save file wasn't readable after the upgrade to version 1.32NA. Nor was it human readable, so I had to try and reconfigure from memory. Second, disabling DNS Relay now causes problems. I thought it was because I forgot to use the Static IP setup on the WAN configuration. But that doesn't fix the weird problems I was seeing. Well, I guess it will take some time to figure out if D-Link has truly fixed the DNS Relay issue it had before this, because I can't disable it without breaking stuff.

Thanks for posting that info Norman !
I have the DIR655 with hardware version A-4 and the original 1.21 firmware version which I think that I will leave the way it is. I can't say that I've noticed any issues with it being configured as a DNS proxy for the eight months that I've owned it.

It is possibly related to PPPoE stuff with DSL service. Cable service uses bridged modems, DSL service often uses combination modem/router devices, which probably should be bridged for use with routers, such as the DIR-655. My SpeedStream 4100 does the PPPoE for ATTIS. I have the A2 hardware version which I upgraded to the 1.21 firmware, and I could set the router for "Static IP" and manually configure the IP address for the SS4100 DHCP issued 192.168.1.64, and set my ATTIS DNS servers manually. Then disable the DNS Relay. Everything worked fine for me that way.

EG, under the Internet setup pages, with your 1.21 firmware, do you see an "Advanced DNS Service" option?

Advanced DNS Service in D-Link router.

Nope. I don't have that option Norman.