Re: Cannot Ping Beyond Default Gateway & DHCP Server
- From: Lem <lemp40@unknownhost>
- Date: Thu, 27 Aug 2009 15:55:26 -0400
dbir wrote:
Final result: my neighbor has broadband! Problem solved.
Although the story has a happy ending, the details are muddled. The problem was definitely in his computer. Nothing was changed on the TW side.
That computer has two ethernet NICs: one from Intel (built-in), and one from Linksys (appears to be a part of the expalsion card with the dial-up recepticals). Most of my testing was with the Intel NIC. I ran Intel's diagnostics on it without problems. And, it was the Intel NIC that worked successfully at my house. Everything described in this thread was through the Intel card.
TW guy came today, and after showing me his TW laptop worked on my neighbor's line (more on that later), he tried the line on the Intel NIC, and it failed as usual. He then plugged it into the Linksys NIC, and much to my surprise, it worked!
I had previously tested that NIC without success. Turns out the difference is (I think), every time he moved a connection, he cleared the modem by unplugging it for 30 seconds. I had not done that. This is an important lesson.
We don't know why the Intel NIC didn't work on my neighbor's line, but worked perfectly on my line. But we no longer care.
The first thing the TW guy did was to plug in his laptop and demonstrate that it worked. But wait, I did not see him change the MAC of his laptop (nor phone anyone). How can that be? Had him do ipconfig /all on his laptop, and his NIC doesn't even have a MAC(!). We talked about MACs. He says he has never had to change a MAC nor tell the home office to change one. I never reached understanding with him on the MAC and how TW uses it to prevent service theft. My assumption now is that this MAC control is occurring in the cable modem, and that clearing it with power off causes it to loose its previously-stored value.
That's all I know. Just wanted to share the end of this story, in case it is useful for someone else in the future.
All's well that ends well. Thanks to everyone who helped.
-Don
"dbir" wrote:
My neighbor finally took the plunge to upgrade from dial-up to cable, but cannot access the internet through it. He’s using XP Home, directly connected to cable modem – service by Time Warner, which works fine for me next door. His dial-up continues to work fine, but access through his Ethernet local area connection does not. TW confirmed (with their own laptop) that the connection & modem are good, so problem must be in his computer.
Network Diagnostics shows pings to his IP, Default Gateway, and DHCP Server work, but pings to DNS servers fail. Verified manually (pings to those DNS from my computer work, so it’s not the DNS themselves). Pings to other IPs (e.g., Google’s) also fail. Connection’s Status shows lots of packets sent, but almost none received. Uninstalled Norton 360 with no effect. No other security software present, Windows Firewall turned off. TCP/IP properties and IP addresses received (DNS, DHCP) look fine (same external IP addresses my computer gets).
Other things checked:
Boot in Safe Mode yields same results. Device Manger shows no problems with Network Adapter or (hidden) TCP/IP drivers. Packet Filtering is off. All Windows components (needed or not) are installed, all services (needed or not) are started or on auto. Windows SFC ran OK.
From all the sage advice I found on this board, here’s what I’ve tried (without success):
reset TCP/IP (netsh int ip reset)
turned off ipsec service (temp)
ipconfig /flushdns
ipconfig /registerdns
So: dial-up works fine, and Ethernet HW/SW gets as far as gateway & DHCP, but can’t get to DNS nor anything else.
I’m a bit over my head, and sure need some advice. Thanks.
Thanks for letting us know.
Your conclusion about the cable modem is correct. When the modem is powered off for the appropriate time (in your case 30 seconds), the MAC address restriction is cleared and the modem then accepts the MAC address of the device next connected to it.
Interestingly, the Linksys NIC doesn't show in the ipconfig /all results you posted on 8/24.
It's possible that with 3 possible wireless configuration utilities (Windows, Linksys, and Intel) installed, there is some odd interaction going on (as a general rule, you should only use one). However, your current position is the correct one -- as long as things are working now, don't mess with them further.
--
Lem -- MS-MVP
Apollo 11 - 40 years ago: http://www.nasa.gov/mission_pages/apollo/40th/index.html
.
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