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IT security is a multi-discipline subject requiring a number of different skills sets and knowledge areas. A key area of knowledge which is vital for any security specialist is a clear understanding of IT infrastructure and how it relates to the creation of a comprehensive security strategy.

== Proxy Service Firewalls ==

A proxy service firewall is placed between the internet and an internal network of computers and acts as a go-between for the two environments. With a proxy service in place, internal client computers do not connect directly to outside resources. Instead they connect to the proxy server which in turn connects with the external resource on behalf of the client, thereby masking the internal IP address of the client. Any responses from the external resources are handled by the proxy service which passes them along to the client that originally requested the data.

The SNMP agent runs on network devices and transmits data to the management station. SNMP version 1 was considered insecure but later versions (2 and 3) have introduction greater levels of authentication (version 2, for example uses MD5 for authentication).

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