The methods described in this chapter are more tentative than in the preceeding two chapters. They don't always work.
<Section 20.1> Finding Persons and Computers
There are a couple of standard methods for checking and verifying E-mail addresses.
% ping rtfm.mit.edu
(Remember that "%" is the prompt the computer gives you. Your system prompt may look different). You should get back a message saying "rtfm.mit.edu is alive" or something like that.
Many machines support a command called "nslookup" that will return the dotted decimal address given the name of the machine
% nslookup rtfm.mit.edu
returns "xxx" as the dotted decimal address.
If you can guess the name of person or institution—this is not hard— then you can try to see if you have a valid address by "fingering" your intended victim:
% finger pdq@hoople.usnd.edu