You can check by ping the domain name in your command prompt (or) Terminal.

Then ping the domain:

1) Open a command prompt. Assuming you have Windows, click Start --> Run, then type cmd and press Enter.

2) Type the following into the command prompt: ping YOURDOMAIN.COM

3) Press Enter

You should see, among other things lines something like this:

Reply from IPADDRESS: bytes=33 time=6ms TTL=56

Reply from IPADDRESS: bytes=33 time=6ms TTL=56

Reply from IPADDRESS: bytes=33 time=6ms TTL=56

Reply from IPADDRESS: bytes=33 time=8ms TTL=56