SANS SEC401 STUDY GUIDE QUESTIONS AND SOLUTIONS
MARKED A+
✔✔OSI Layer 7 - Application - ✔✔manages access requests from a program to a
network; web application talking to a web server
✔✔OSI Layer 6 - Presentation - ✔✔Ensures that info sent at application layer of one
system is readable by the application layer of another system. May translate between
multiple data formats by using a common format. could decompress files
✔✔OSI Layer 5 - Session - ✔✔Establishes, manages, and terminates sessions
between two communicating hosts. Synchronizes dialog between the presentation
layers of the two hosts and manages their data exchange.
✔✔OSI Layer 4 - Transport - ✔✔The functions defined in this layer provide for the
reliable transmission of data segments, as well as the disassembly and assembly of the
data before and after transmission across a network. sequencing of packets in a
transmission
✔✔OSI Layer 3 - Network - ✔✔The routing layer (IP addresses, routers, packets)
✔✔OSI Layer 2 - Data Link - ✔✔connects physical part of network (cables and electrical
signals) w abstract part (packets and data streams)
✔✔OSI Layer 1 - Physical - ✔✔Electrical, mechanical, procedural, functional
specifications for activating, maintaining, and deactivating the physical links between
end systems. Examples of L1 devices, transceivers, modems, CSU/DSU, and hubs
✔✔Please Do Not Throw Sausage Pizza Away - ✔✔physical, data link, network,
transport, session, presentation, application- OSI model
✔✔protocol headers - ✔✔information that contains what each OSI Layer did to the data
to tell the other protocol stack what was done
✔✔Decapsulation - ✔✔reading and Removing a header or trailer from a lower OSI layer
✔✔Encapsulation - ✔✔moving down an OSI stack and adding headers to describe work
done by previous layer
✔✔tcp/ip - ✔✔Transmission Control Protocol/internet protocol
✔✔TCP/IP - ✔✔IRL application of communication protocol b/w networks
1) application
, 2) transport (tcp)
3) internet (ip)
4) network
✔✔IP - ✔✔what is the core routing protocol of the internet?
✔✔OSI Layer 3 - Network - ✔✔what osi layer does ip work at
✔✔osi Layer 3 - Network - ✔✔Which layer of the OSI model does a router operate?
✔✔primary purpose of ip - ✔✔handle transmissions of packets between network
endpoints; only to find the best path, not guarantee delivery. it is up to other protocols to
guarantee
✔✔IPv4 - ✔✔IPV4 was designed for arpanet for A defense-related computer network
that was the precursor to the internet. by DARPA. accommodates 4.2 billion 32-bit
addresses
✔✔IPv6 - ✔✔128 bits 340 undecillion addresses
✔✔IPv4 vs IPv6 - ✔✔IPv4: no authentication; encryption provided by applications; best
effort transport
IPv6: provides authentication of endpoints; support for encryption in protocol; quality of
service (QoS) features provided in protocol
✔✔3 areas of cybersecurity perspective in communication framework - ✔✔availability,
Confidentiality, integrity
✔✔IPv4 Header - ✔✔Version, length, TTL, Protocol, Source / Target. 20 - 60 Bytes,
resides on internet layer (2) for TCP/IP model and network layer (3) for OSI model
✔✔IPv4 header- IP version - ✔✔4 bits; either has value of 4 or 6; IPv4 or IPv6
✔✔IPv4 header- protocol - ✔✔8 bits; identifies encapsulated (which comes next)
protocol; TCP packet=6(decimal); UDP packet=17(decimal); ICMP packet=1(decimal)
✔✔IPv4 header- TTL - ✔✔8 bits; time to live; # of hops a packet is allowed to take
between routers before expiring (so there's no infinite # of hops taking up router
resources like a DoS); any # between 0 and 255
✔✔IPv4 header- fragmentation - ✔✔16 bits; (13 bits fragment offset and 3 bits for flags);
used to break up larger packets into smaller ones if a router can't transmit a large
packet; tells where each part goes so it can be reconstructed at next destination
MARKED A+
✔✔OSI Layer 7 - Application - ✔✔manages access requests from a program to a
network; web application talking to a web server
✔✔OSI Layer 6 - Presentation - ✔✔Ensures that info sent at application layer of one
system is readable by the application layer of another system. May translate between
multiple data formats by using a common format. could decompress files
✔✔OSI Layer 5 - Session - ✔✔Establishes, manages, and terminates sessions
between two communicating hosts. Synchronizes dialog between the presentation
layers of the two hosts and manages their data exchange.
✔✔OSI Layer 4 - Transport - ✔✔The functions defined in this layer provide for the
reliable transmission of data segments, as well as the disassembly and assembly of the
data before and after transmission across a network. sequencing of packets in a
transmission
✔✔OSI Layer 3 - Network - ✔✔The routing layer (IP addresses, routers, packets)
✔✔OSI Layer 2 - Data Link - ✔✔connects physical part of network (cables and electrical
signals) w abstract part (packets and data streams)
✔✔OSI Layer 1 - Physical - ✔✔Electrical, mechanical, procedural, functional
specifications for activating, maintaining, and deactivating the physical links between
end systems. Examples of L1 devices, transceivers, modems, CSU/DSU, and hubs
✔✔Please Do Not Throw Sausage Pizza Away - ✔✔physical, data link, network,
transport, session, presentation, application- OSI model
✔✔protocol headers - ✔✔information that contains what each OSI Layer did to the data
to tell the other protocol stack what was done
✔✔Decapsulation - ✔✔reading and Removing a header or trailer from a lower OSI layer
✔✔Encapsulation - ✔✔moving down an OSI stack and adding headers to describe work
done by previous layer
✔✔tcp/ip - ✔✔Transmission Control Protocol/internet protocol
✔✔TCP/IP - ✔✔IRL application of communication protocol b/w networks
1) application
, 2) transport (tcp)
3) internet (ip)
4) network
✔✔IP - ✔✔what is the core routing protocol of the internet?
✔✔OSI Layer 3 - Network - ✔✔what osi layer does ip work at
✔✔osi Layer 3 - Network - ✔✔Which layer of the OSI model does a router operate?
✔✔primary purpose of ip - ✔✔handle transmissions of packets between network
endpoints; only to find the best path, not guarantee delivery. it is up to other protocols to
guarantee
✔✔IPv4 - ✔✔IPV4 was designed for arpanet for A defense-related computer network
that was the precursor to the internet. by DARPA. accommodates 4.2 billion 32-bit
addresses
✔✔IPv6 - ✔✔128 bits 340 undecillion addresses
✔✔IPv4 vs IPv6 - ✔✔IPv4: no authentication; encryption provided by applications; best
effort transport
IPv6: provides authentication of endpoints; support for encryption in protocol; quality of
service (QoS) features provided in protocol
✔✔3 areas of cybersecurity perspective in communication framework - ✔✔availability,
Confidentiality, integrity
✔✔IPv4 Header - ✔✔Version, length, TTL, Protocol, Source / Target. 20 - 60 Bytes,
resides on internet layer (2) for TCP/IP model and network layer (3) for OSI model
✔✔IPv4 header- IP version - ✔✔4 bits; either has value of 4 or 6; IPv4 or IPv6
✔✔IPv4 header- protocol - ✔✔8 bits; identifies encapsulated (which comes next)
protocol; TCP packet=6(decimal); UDP packet=17(decimal); ICMP packet=1(decimal)
✔✔IPv4 header- TTL - ✔✔8 bits; time to live; # of hops a packet is allowed to take
between routers before expiring (so there's no infinite # of hops taking up router
resources like a DoS); any # between 0 and 255
✔✔IPv4 header- fragmentation - ✔✔16 bits; (13 bits fragment offset and 3 bits for flags);
used to break up larger packets into smaller ones if a router can't transmit a large
packet; tells where each part goes so it can be reconstructed at next destination
