Java Reference
In-Depth Information
Whois
Whois is a simple directory service protocol defined in RFC 954; it was originally de‐
signed to keep track of administrators responsible for Internet hosts and domains. A
whois client connects to one of several central servers and requests directory informa‐
tion for a person or persons; it can usually give you a phone number, an email address,
and a snail mail address (not necessarily current ones, though). With the explosive
growth of the Internet, flaws have become apparent in the whois protocol, most notably
its centralized nature. A more complex replacement called whois++ is documented in
RFCs 1913 and 1914 but has not been widely implemented.whois directory service
protocol)
Let's begin with a simple client to connect to a whois server. The basic structure of the
whois protocol is:
1. The client opens a TCP socket to port 43 on the server.
2. The client sends a search string terminated by a carriage return/linefeed pair (\r\n).
The search string can be a name, a list of names, or a special command, as discussed
shortly. You can also search for domain names, like
www.oreilly.com
or
net‐
scape.com
, which give you information about a network.
3. The server sends an unspecified amount of human-readable information in re‐
sponse to the command and closes the connection.
4. The client displays this information to the user.
The search string the client sends has a fairly simple format. At its most basic, it's just
the name of the person you're searching for. Here's a simple whois search for “Harold”:
$
telnet whois.internic.net 43
Trying 199.7.50.74...
Connected to whois.internic.net.
Escape character is '^]'.
Harold
Whois Server Version 2.0
Domain names in the .com and .net domains can now be registered
with many different competing registrars. Go to http://www.internic.net
for detailed information.
HAROLD.LUCKYLAND.ORG
HAROLD.FRUGAL.COM
HAROLD.NET
HAROLD.COM
To single out one record, look it up with "xxx", where xxx is one of the
of the records displayed above. If the records are the same, look them up
with "=xxx" to receive a full display for each record.
