Can nslookup a Domain, But Cannot Ping the Domain

I came across a really weird issue with my little sister’s computer today and thought I would share my experience to see if anyone else has experienced something similar or perhaps might have a solution for the issue. For the moment her computer looks like it will have to be formatted and have the OS reinstalled, though I would rather not have to do that.

Her computer is running Windows XP with Service Pack 3 and has been having issues lately. They (my sister and mum) believe they remember seeing a message seeing that Windows was recently updated and ever since that, they have not been able to visit any website using MSIE or Firefox.

My Mum called the ISP’s (Shaw) technical support and even though they (Shaw) could ping the computer behind the modem (after the router was removed from the equation) the technician could not really suggest any more recommendations in troubleshooting the problem. After all, the technical support representative could establish a connection between his node and the mode what more could he do, right?.

When my mum told me about the issues they were having, she mentioned that my sister could still download music via Limewire (ugh) but they could not surf to any of their favorite websites. Seems a bit odd but it was time for me to try and work my troubleshooting magic.

Now for the network administrators out there reading this you may say something along the lines of it being a DNS issue; I can ping an IP address but I cannot ping the associated domain. Well it seems like it but if I use a manual DNS entry like 4.2.2.2 (which I can ping without issue), domain names still return unresolvable.

Alright so what else did I try? Well I could do nslookups [wiki] on domain names and have it return their IP addresses, such as google.com, I just couldn’t ping google.com. I could ping them by IP though. In fact I used the IP address of Google to scourer the interweb for issues related to this; ‘winxp cannot ping domain but can ping IP’ and a lot of the results returned people using a popular Window XP Winsock utility that was supposed to fix a Winsock issue. That did not solve the issue either.

I looked into the /system32/driver/etc/host file and all the other files that are located in that directory of the Windows XP installation and there was nothing strange about them either, no rogue entries.

I thought perhaps it was the TCP/IP stack so I rebuilt the stack and still could not resolve domain names.

I moved the PCI NIC into another available PCI slot on the motherboard and had the machine install the drivers again, but again no such luck. I even removed the existing NIC and installed another brand of NIC into the motherboard, even which did not solve this peculiar issue.

I went to look at recent Windows Updates via the Add/Remove Program panel and removed the 3 latest patches one of them which was Service Pack 3. Unfortunately it would allow me to remove SP3 because it kept erroring (Cyclic Redundancy Check errors [wiki]) on various files. Oh, perhaps it’s a failing hard drive? Not a good solution to my issue though. Oh did I mention that it took at least 20 minutes for the Add/Remove Programs to load the software that is installed in the machine? Usually not a good sign and some websites suggested it could be virus based. Oh boy, a Virus? I didn’t have time to run a virus scan.

Booting into save mode and using a command prompt would not solve this quirky issue of not being able to ping domains but allow me to still find out the domain’s IP address.

I have flushed the DNS table, cleared the ARP table, rebuilt the TCP/IP stack, removed/replaced NICs and more and after about 3 hours I was still unable to figure out the issue.

At this point I recommended it was best to format the machine and reinstall Windows XP. It would also (hopefully) clear up some other issues my sister has mentioned she has experienced recently as well (software wise).

So, have I exhaust all my available resources for this odd occurrence? I would have tried to boot the machine using a Linux Live CD to make sure it was not hardware related, but I didn’t have one available to try out.

So what else is there to try for a computer in which you cannot ping domain names, but you are able to do nslookups against domain names to find out their IP addresses in which you can then ping. I find it pretty bizarre, do you?