I have a Dell PowerConnect 7048 with 48 PCs connected to it. There is one particular URL that I cannot ping or browse from any PC. Every other URL/Site works without any problem.
I plugged five of the 48 PCs direct into the router and the URL worked fine. So it is not the PC, DNS, ACL, blacklist or IE settings.
I dont have any proxy in my network. I think the problem is in the switch, which by the way has no Vlans or any other configuration. It is pretty much the factory settings.
Can you ping by IP instead of by name?
Are you sure you don't have a rogue Router / DHCP server / DNS server on your network?
Can you confirm you are getting the same IPCONFIG /ALL (IP, DNS server, DHCP server) from computers connected to the router and to the switch?
if you TRACERT 220.127.116.11, do you get the same results from both locations?
What about forcing the DNS server in TCP/IP setting to 18.104.22.168; then can you ping the URL?