Services which contain libwrap module can use hosts.deny to control Access
ldd  /usr/sbin/vsftpd    |grep libwrap
ldd  /usr/sbin/sendmail  |grep libwrap
ldd  /usr/sbin/sshd      |grep libwrap

To Restrict a host/network  to control access to a Service.

1.  Using Hostname/Domainname
vim /etc/hosts.deny
vsftpd                     ->All hosts in domain denied to access ftp
vsftpd                ->Host server in denied to access

2.  Using  Ipaddress/Network
vim /etc/hosts.deny
vsftpd         ->All hosts in 1.0 N/W denied.
vsftpd                       ->Host 1.4 denied.

3.  To  Deny all Except few
vim /etc/hosts.deny
sshd: ALL  EXCEPT            ->Any domain other than are denied the Access to ssh.

4. To  Allow all Except few
vim /etc/hosts.allow
ALL:  EXCEPT  ->All hosts are allowed to connect to all services except

Both entries allow/deny can be given in either hosts.allow or hosts.deny file


Reset root password with FreeBSD

1) Boot into single user mode, (at the FreeBSD boot loader, enter ’4′ to boot into single user mode)

2) When prompted Enter full pathname of shell or RETURN for /bin/sh:

3) Press Enter key to boot into single user mode.

4) Next, you will be immediately dropped into a single user mode without a root password.

5) Remount / (root) file system in read and write mode with mount command,

#mount -u /

#mount -a

6) Enter the new password with passwd command:


7) Next, type ‘exit’ to boot FreeBSD.