Bastion Host

Under a bastion host is meant a server that offers services to the public Internet or accessed as a proxy and mail server on the public Internet and therefore must be protected, particularly against attacks.

Configuration

Network topology

To protect the server is placed in a network that is both over the Internet and the internal network protected by a firewall. Such a network is referred to as a demilitarized zone. The firewalls used which ensure this separate network, this should be as restrictive as possible configured. For example, the direct access from the internal network to the Internet should not be possible. Also, only the ports should be released, which are required for operation. A web server will not build up their own requests to other Web servers on the Internet generally. Therefore, the establishment of a connection to a port 80 through the firewall should be prohibited.

Spatial placement of the server

Such a computer should be placed in a room to which only authorized persons have access.

Installation and configuration of software

In the configuration of such a computer is to make sure that only the software is installed, which is required necessarily for the operation of the computer. During installation care should be taken that only the absolutely necessary for the operation of features to be installed. In addition, the applications should be provided only with the permissions are strictly for the operation. The installation of development environments should be avoided in order not to support hackers by providing appropriate tools during a burglary. And the operation of multiple services on a computer should be avoided since this increases the risk of attack.

Monitoring and Operations

The operation of such a unit should be performed only by experienced administrators, as constant monitoring of the activities required by an analysis of the log files. In addition, the administrator should inform about news became known vulnerabilities in order to ward off a threat to the system in advance can.

Here, the administrator must be able to assess whether the reported vulnerability for the affected system is relevant to possibly be protected by appropriate configuration of the system or installing a patch the system against attacks.

Security policies

In order to avoid wrong decisions in crisis situations, it is desirable to establish security policies, in which, inter alia, rules of conduct should be included in the event of a successful attack. Also should be clearly defined for appropriate decisions in such a document the organizational responsibilities.

Also, for planning such policies can be helpful in order to avoid possible errors in advance.