Oops!!!!

Doing this opens a security exploit for any local users to become other
users including root on some systems. You don't want to do this unless you
have a single user (well, root and interbase) box. IIRC, linux never trusts
root unless there is a .rhosts in ~root. But users could become other users
such as interbase, and steal their files (such as databases) and put them on
systems with different passwords in isc4.gdb, thus bypassing database
security and user file permissions.

3. Add localhost.localdomain to /etc/hosts.equiv:
echo localhost.localdomain >>/etc/hosts.equiv