ftp bombs with shell other than c*sh

[Douglas P. Kingston]

This question can be answered by reading the manual.

ftpd on 4.0 (and 4.3BSD) checks the file /etc/shells to see if the user
has a valid login shell.  If /etc/shells does not exist, the shell must be
/bin/sh or /bin/csh (or null).

To quote from the ftpd(8) man page:
    "ftpd authenticates users according to three rules.

     1)   ...

     2)   The  user  must  have  a  standard  shell  returned  by
          getusershell(3).

     3)   ...

-Doug-