Securing and Optimizing Linux: RedHat Edition -A Hands on Guide
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16.5. Configure sshd2 to use tcp-wrappers/inetd super server

Tcp-wrappers shoud be enabled to start and stop the sshd2 server. Upon execution, inetd reads its configuration information from a configuration file which, by default, is /etc/inetd.conf. There must be an entry for each field of the configuration file, with entries for each field separated by a tab or a space.

  1. Edit the inetd.conf file, vi /etc/inetd.conf and add the line:

    
         ssh      stream  tcp     nowait  root    /usr/sbin/tcpd  sshd -i

    Important: The -i parameter is important since it specifies that sshd is being run from inetd. Also, update your inetd.conf file by sending a SIGHUP signal, killall -HUP inetd after adding the above line into the file.

    To update your inetd.conf file, use the following command: 
    
         [root@deep] /#killall  -HUP inetd

  2. Edit the hosts.allow file, vi /etc/hosts.allow and add the line:

    
         sshd: 192.168.1.4 win.openna.com
    Which means client 192.168.1.4 with host name win.openna.com is allowed to ssh on the server.

    Note: These daemon strings for tcp-wrappers are in use by sshd2:

    sshd, sshd2

    The name sshd2 was called with usually sshd.

    sshdfwd-X11

    if you want to allow/deny X11-forwarding.

    sshdfwd-<port-number>

    for tcp-forwarding.

    sshdfwd-<port-name>

    port-name defined in /etc/services. Used in tcp-forwarding.

Tip: If you do decide to switch to using ssh, make sure you install and use it on all your servers. Having ten secure servers and one insecure is a waste of time.

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Configure the /etc/ssh2/sshd2_config file Up Configuration of the /etc/pam.d/ssh file