Question : Weird Networking Problem

Dear All,

Here's the scenario. The company recently upgraded from a 512k ADSL link to a 1M SHDSL link, with all WAN IPs retained. The setup:

Private LAN (10.131.17.x) f/a0 |--- Cisco 1814 ---| WIC-4ESW |--- SpeedTouch ST610s ---|  ----->> Internet

IP Addresses:
=========

1814's WIC: 58.185.xx.193 /28
ST610s Inside: 58.185.xx.194 /28
ST610s WAN: 203.115.xx.78 /30
ISP: 203.115.xx.77 /30

After setting up the ST610s, I connected back everything as it originally was. I then plugged my laptop from 1814's fa0, could ping all the way the ISP's IP (203.115.xx.77) but I just couldn't surf the net (from any other workstations). I tried doing a ping to the ISP's DNS without problems too. Whenever I launch IE, it just shows the page cannot be displayed. I've entered the DNS servers correctly on the ST610s and should I plug my laptop directly to the ST610s, I could surf without problems (therefore, it can't be a virus problem). I'd like to add that I have no access to the 1814. Any ideas?

Cheers.

Answer : Weird Networking Problem

Ping isnt the best way to test DNS connectivity. Open a command prompt and type:

NSLOOKUP

If there is a DNS configuration, NSLookup will connect to its primary DNS server. If not, you can issue the following command from DNS command line:

server IPAddressOfTheDNSServer

Then, it will try to connect to the DNS server.

If you have got a connection to DNS, try a search. Type some site name and see if its is resolved. For example:

www.microsoft.com

If your DNS doesn't responds, you may have a firewall issue. Open port 53 on firewall and try again.

If all your DNS config and results are OK, type Exit to quit NSLOOKUP and try a Telnet to www.microsoft.com to see if port 80 is not blocked:

telnet www.microsoft.com 80

You should see a black screen. This means that its connected. Or just test a connection from the web browser. If you cannot connect, try checking your firewall.