Page 102 - DCAP309_INFORMATION_SECURITY_AND_PRIVACY

Information Security and Privacy

Notes 7.4 Trusted and Untrusted Networks

7.4.1 Trusted Network

Trusted networks are defined as “the networks within your security boundary, and are typically
the networks you are trying to defend.”

Computers on the trusted network can clearly access such departmental services as NFS (home
and project disks), NIS (distributed account and other information), printers, software packages,
etc. Access to this network is restricted to machines supervised by the Lab Staff, so as to protect
sensitive data and uphold the accessibility of departmental resources. A current list of machines
on the trusted network can be located here.

!
Caution Users should not effort to attach their individual machines to this network.

7.4.2 Untrusted Network

Mostly, computers on the untrusted network are managed and configured by their possessors.
Because this could potentially permit improper access to sensitive or private data, or could cause
operational trouble to the production computer network, these machines are cut off on a separate
subnet, and are not specified direct access to many core departmental computer services.
Untrusted network is considered as “the networks external your security perimeter. They are
untrusted since they are frequently away from your control.” Alternatively, untrusted networks
are those that may provide services or information that you require to access, but since you are
not in control of supervising these networks, they are “untrusted” in the sense that you restrict
the communications among them and your network.

Example: An example of this might be a client network you attach to obtain access to
some information.

There are also “unknown” networks, which would comprise any network not purposely defined
in your firewall’s configuration, which would comprise the majority of the networks you see on
the Internet.
Self Assessment

Fill in the blanks:
10. ................. networks are defined as “the networks within your security boundary, and are
typically the networks you are trying to defend.”
11. ................. network is considered as “the networks external your security perimeter.
12. Untrusted networks are also “.................” networks, which would comprise any network
not purposely defined in your firewall’s configuration, which would comprise the majority
of the networks you see on the Internet.

7.5 Unknown Attacks

To avoid highly injurious “superworms” or hackers by means of unknown or unpatched exploits,
unusual solutions are required that are intended to avert and react to unknown attacks, instead

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