43.2.1.1.2. TCP Wrappers and Attack Warnings

43.2.1.1.2. TCP Wrappers and Attack Warnings

If a particular host or network has been detected attacking the server, TCP Wrappers can be used to warn the administrator of subsequent attacks from that host or network using the spawn directive.

In this example, assume that a cracker from the 206.182.68.0/24 network has been detected attempting to attack the server. Place the following line in the /etc/hosts.deny file to deny any connection attempts from that network, and to log the attempts to a special file: 

 ALL : 206.182.68.0 : spawn /bin/ 'date' %c %d >> /var/log/intruder_alert

The %d token supplies the name of the service that the attacker was trying to access.

To allow the connection and log it, place the spawn directive in the /etc/hosts.allow file.

Note

Because the spawn directive executes any shell command, create a special script to notify the administrator or execute a chain of commands in the event that a particular client attempts to connect to the server.


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