=?Utf-8?B?RmVsaXg=?= wrote in
:

Running Windows XP SP3 on HP7900 PC. Not apart of a domain
(WORKGROUP) and is only intended for access to the Internet only
and serve apps that are installed. I have 7 - 8 lab PCs that
specifically do not list DNS servers in IPCONFIG and their OS
network settings are set to 'Obtain DNS server address
automatically'. Same for DHCP settings (automatic). Network Admins
have been notified but they point to local PC being issue. I can
ping the DNS server IP Addresses listing on a neighboring known
working PC and I can ping 127.0.0.1, but I can't ping IP Address
nor name of basic websites like yahoo.com and google.com.

This is what I've done thus far...

1. On all PCs reported no longer showing DNS settings in IPCONFIG,
they have a FIVE minute DHCP lease window as opposed to known
working student lab PCs who's leases expire every seven days.

2. NSLOOKUP results on reported faulty lab PCs is 'Default servers
are not available'.

3. Cross-checked faulty PCs HOST file with known working lab PCs
HOST file and all is in order.

4. Cross-checked faulty PCs browser Internet Options with known
working lab PC. They both mirror one another.

5. Swapped a reported faulty lab PCs CAT5 from wall jack and
plugged into an adjacent known working lab PC's wall jack (RJ-45).
The faulty lab PC still would not resolve website names after
reboot. Still no DNS settings in IPCONFIG. Plugged known working
student lab PCs CAT5 into faulty PCs old wall jack and the known
working lab PC still successfully resolves website names in IE8
and DNS settings promptly list in IPCONFIG.

Same results on 2 - 3 other reported faulty lab PCs that do not
have DNS settings.

Isolated issue to local PC(s).

6. Issue was prevalent since late last week. I ran System Restore
from a week or more ago. After reboot, still no DNS.

7. Ran Malwarebytes full virus scan overnight. Found and removed
six viruses. Reboot and issue still exists.

8. Reset IP stack as well as uninstalled/reinstalled NIC...no
results either.

9. Safe Mode with Networking yields same results.

10. Ran Winsock and LSP Fix. Neither results corrected issue. LSP
app actually listed files that it generated as 'No Problems
Found'. Still no result after reboot.

11. Attempted to manually enter DNS IP addresses statically into
OS...still did not take. Reboot, no success.

Network connectivity icon in lower right of monitor on faulty PCs
always display 'Speed: 100.0 Mbps'/'Status: Connected'

Any ideas or suggestions would be greatly appreciated!



Very thorough post.

First, check the obvious:

Start-Run-"services.msc"
Then check the list and make sure that "DHCP Client" and "DNS Client"
are both present and the status is listed as "Started" and Startup Type
is "Automatic".

If that checks out, then you must then realize that the DNS Servers are
assigned by the DHCP server. The fact that your DHCP lease is only 5
minutes is potentially another indication that something is wrong with
your DHCP assignment by the server. At this point I would determine
whether this is a DHCP server issue or a Windows issue by booting your
machine to Linux. Create a free Live Linux CD (such as Knoppix) and
boot your machine from the CD. If the machine boots and properly
registers a DNS server, then you have a Windows problem. If not, you
probably have a DHCP server problem.

Knoppix: http://www.knopper.net/knoppix/index-en.html

Another thing you can try is to install a packet capture program like
freeware "Wireshark". Then bring up a command window (Start-Run-Cmd)
and release your current IP with the command:
ipconfig /release
Then start a packet capture with Wireshark and initiate a DHCP
acquisition request by entering the following command in the command
window:
ipconfig /renew
You can stop the capture a few seconds after the command.

Try this on both a good and bad machine. You will be able to see the
DNS assignment in the packet captures (or not). Wireshark will decode
the fields for you. Look for "DHCP" in the "Protocol" column in the
capture.

Wireshark: http://www.wireshark.org

Good luck.
Hope this helps,
John