If you know where the user in question has an account, you can try `finger' to see his login name:
behr % finger -l Prais@corn.cso.niu.edu [corn.cso.niu.edu] Login name: mgprais In real life: Michael G. Prais Directory: /user1/acs/mgprais Shell: /bin/cshThis doesn't always work; some finger implementations will not return partial matches, and finger is disabled altogether on some machines for security reasons.
behr % ph
ph> query stankus
----------------------------------------
name: Stankus, Mark
curriculum: Student-At-Large Education
email to: mstankus@niu.edu (no account registered)
----------------------------------------
name: Stankus, Randi Coleen
curriculum: Pre-Elementary Education
email to: rstankus@niu.edu (z957798@oats.farm.niu.edu)
----------------------------------------
ph> quit
In this case I searched for an undergraduate student. The first match
tells me that Mark is in the database, but has not set his real e-mail
address correctly. A letter mailed to mstankus@niu.edu will
bounce back. If you are using e-mail to communicate with your students,
you should tell them that simply getting an account is not enough;
they also need to go to one of the computer labs, and execute an
application called `newuser', which completes the registration
process.The second match says that Randi does have a real account on the oats.farm computer, and her login name there is z957798. You can use either the real address, z957798@oats.farm.niu.edu, or the ph `nickname' rstankus@niu.edu. In both cases the letter will end up in her mailbox on oats.
You can get more information on using the nameserver database here.
The WPO mail system, however, is linked to the Internet world with a gateway which makes it possible to send and receive letters to/from that system. When someone gives you an e-mail address of the form a02jwn3 (administrative department code, initials, and a digit), chances are that they use WPO. To send a letter to that person, use the address a02jwn3@wpo.cso.niu.edu, and tell him that he should prepend internet: to your address, e.g. internet:behr@math.niu.edu.
Unfortunately few WPO users are registered with the ph database, and there is no low-tech method for finding their addresses at this time.