CompTIA Security+ Certification - Courseware - Firebrand Training

142 Pages·2014·2.3 MB·English

by  Richard Millett

COMPTIA Security+

Version 4.0
Courseware
www.firebrandtraining.com
CompTIA Security+
Introduction
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Exam Details
Exam SY0-401
Duration 90 Minutes
90-100 questions
Questions contain simulations which are
interactive
Passing score 750/900
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CIA
One of the main tenets of security is CIA
Confidentiality – protecting the data from unauthorised
access through controls and encryption
Integrity – ensuring that the data has not been
tampered with or altered during transmission,
preventing unauthorised changes
Availability – the data is available when needed to
those authorised to receive it
System and network security is built around these main
principles
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Section 1
Network Security
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Objectives
Network devices and Technologies
Secure network administration
Network design elements
Implementing common protocols
Commonly used ports
Implementing secure wireless networks
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Network Security
Network devices fulfil a number of roles within todays networks
and include the following:
Firewalls
Routers
Switches
Load Balancers
Proxy Servers
VPN Concentrators
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Firewalls
The primary function of a firewall is to provide protection for a
network by preventing unwanted traffic entering from other
networks
Most commonly used at the perimeter of a private network to
protect it from the public Internet
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Firewalls
In simple terms a firewall is device with two (or more) network
interfaces that can examine the traffic between two networks and
only allow traffic through that has been defined as allowable
The basic form of firewall is a packet filter that looks at source
and destination information such as addresses , port numbers,
protocols and makes forwarding decisions on that information
A packet filter examines the information contained in TCP and IP
packet headers
A packet filter works at layers 3 & 4 of the OSI model
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Firewalls
Circuit level gateways include layer 5 of the OSI model and base
the forwarding decisions on the connections between the two
endpoints as well as address information
Application level gateways work at layer 7 of the OSI model and
are application specific as in web gateway that examines HTTP
traffic
Application gateways can examine the data packets so can filter
on HTTP requests and content returned
Another term for application gateway would be proxy server
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Firewalls
Stateful multilayer Inspection Firewall
This one combine the functions of the previous firewall types and
works from layers 3 to 7 of the OSI model and examines all aspects
of packets, headers and data.
This also looks at the state of the TCP flags to ensure the
connection is valid and has been setup in the right direction i.e. it
will allow a connection from inside to out but not from outside to
in
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Routers
Routers are used to connect network segments together at layer 3
the network layer
They connect IP subnets together
Routers pass traffic towards the destination based upon the
destination IP address of the packet.
They base forwarding decisions upon information in their routing
tables
The routing tables are built using either static entries or based
upon information passed between routers using routing protocols

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Routers
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Switches
Switches connect devices together at layer 2 of the OSI model the
Datalink layer
They move frames between switch ports by looking at the
destination MAC address
Switches hold a MAC address table in memory that lists which MAC
addresses are visible on which ports
If the switch does not know which outbound port to use it floods
the frame to all ports
Switches can be connected together to propagate the traffic to
further devices at layer 2

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Switches
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Load Balancers
A load balancer is used to distribute traffic between two or more
devices
Load balancers can be used to maximise throughput and speed up
response times
Commonly found in front of a group of webservers to distribute
requests across multiple servers

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Proxy Servers
Proxy Servers fulfil a number of roles within the network
environment
The proxy server sits between the client and the Internet and acts
as a go between for web requests
Their primary role was originally caching where they maintained
copies of web content on the proxy to be returned to clients that
requested it thus reducing bandwidth requirements
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Proxy Servers
The Proxy server, because of its position between client and
Internet, can provide NAT – address translation so it can protect
the clients by mapping the private to public addresses
The proxy logs all traffic that goes through. This was originally to
help tune the cache and ensure the correct content was loaded
but now has the advantage of producing a record of who goes
where
The proxy can also be used to control who goes where. Filters can
be applied so users cannot access undesirable content from the
Internet
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