How do I translate a URL to an IP address?

A "URL" is a full specification to a page. For example:

http://ask-leo.com/who_is_leo.html

Is a URL. It has three parts:

• The protocol specifier: http:

• The domain name: ask-leo.com

• The page location: /who_is_leo.html

The protocol specifies the port that will be used. http, for example, is port 80. ftp uses ports 20 and 21. SMTP, the mail sending protocol, is usually on port 25. You can actually find the full list of "official" ports here.

It's only the domain name that has an IP address associated with it. So that's what you would be looking up.

My approach is to use the "ping" command in a Windows command prompt. For example:

C:\>ping ask-leo.com

Pinging ask-leo.com [72.3.133.152] with 32 bytes of data:

Reply from 72.3.133.152: bytes=32 time=65ms TTL=48
Reply from 72.3.133.152: bytes=32 time=67ms TTL=48
...

All you need is that first line, which tells you exactly what IP address the domain "ask-leo.com" resolves to.

Obviously the ping command does more, but it's easy and a habit I've gotten into for figuring out IP addresses quickly.

If you want a lot more information about a domain, then there are several tools out on the web that are worth looking into. One easy one is samspade.org. A single field into which you enter the domain name you're interested in, press WhoIs and you'll get a report much like this:

As you can see it displays the same IP address as above, as well as the registration and contact information about the domain.

There are a couple of catches with this type of lookup:

• Not all registrars will show up this easily or quickly. Often you'll be redirected automatically or manually to another "WhoIs" lookup service that's hosted by the actual domain registrar.

• Some folks go to great lengths to hide their domain ownership. Either by registering with false information, or by using a privacy service, the information presented here isn't always exactly what you're looking for. But it's a start.