Wu-ftpd comes with built in support to make it virtual. However, you
cannot maintain separate password files for each domain. For example, if
bob@domain1.com
and bob@domain2.com
both want
an account you would have to make one of them bob2 or have one of
the users choose a different user name. Since you now have a virtual
filesystem for each domain you have separate password files and this
problem goes away. Just create a virtnewuser script and virtpasswd
script in the way mentioned above and you are all set. You can
also have anonymous ftp in each virtual environment as that would
be unaffected by the virtual filesystem as well.
The inetd.conf entries for wu-ftp:
ftp stream tcp nowait root /usr/bin/virtuald virtuald /virtual/conf.ftp wu.ftpd -l -a