Is the encrypted password's salt simply random?

[Glenn F. Leavell]

I'm writing a simple C program to encrypt passwords, so that I can call
it from a shell script when generating new accounts.  To generate the
encrypted password, I'm making use of the crypt() function:

	char *crypt( char *password, char *salt )

I'm using a randomly generated two-character salt from the set [a-zA-Z0-9./],
and everything seems to be working fine.  Here's my question:  is this
the right way to choose the salt - just a random thing?

Please follow-up to comp.unix.admin.  Thanks in advance!
--  
Glenn F. Leavell  Systems Administrator  glenn at rigel.econ.uga.edu  404-542-3488
 University of Georgia Economics Department. 147 Brooks Hall. Athens, GA 30602