4. Communications And Network Security Flashcards
What is the OSI model mnemonic?
All People Seem To Need Data Processing
What is the 7th level of the OSI model, and an example?
Application
Example: data
What is the 6th level of the OSI model, and an example?
Presentation
Example: data
Present data in a format that all computers can understand.
The ONLY layer without any protocols.
Concerned with (file level) encryption, compression and formatting.
What is the 5th level of the OSI model, and an example?
Session
Example: data
Responsible for establishing a connection between two applications (either on the same or different computers).
What is the 4th level of the OSI model, and an example?
Transport
Example: segments
Pervades end-to-end data transport between two machines.
Protocols used here: SSL/TLS, TCP, UDP.
What is the 3th level of the OSI model, and an example?
Network
Example: packets
What is the 2nd level of the OSI model, and an example?
Data
Example: frame, dumb switches.
What is the 1st level of the OSI model, and an example?
Physical
Example: bits
What are common threats to the 1st level of the OSI model?
Theft, unauthorized access, vandalism, sniffing, data emanation.
How do switches in the 2nd layer of the OSI model direct traffic?
They use IP addressing to direct traffic and isolate traffic into broadcast domains.
Is a layer 3 switch necessary for inter-VLAN communication?
No, layer 2 switches can perform this function.
What are the frequently exploited attacks for layer 3 of the OSI model?
Loki - sending data in ICMP headers(as a covert channel).
Ping of Death - violates the MTU (maximum transmission unit) size.
Ping floods - lots of ping traffic
SMURF - uses spoofed source address (target) and directed broadcasts to launch a DDoS.
In what case is UDP better to use then TCP?
When “real time” transfer is essential. Media streaming, gaming, etc.
What kind of firewall is at the 3rd layer of the OSI model?
Packet filters
- uses ACL to control access.
- not stateful, just looks at the network and transport layers.
What kind of firewall is at the 5th layer of the OSI model?
Stateful Firewalls
- router keeps track of connections table.
What kind of firewall is at the 7th layer of the OSI model?
Application Firewalls
- NAT/PAT
—NAT allows one-to-one mapping of IP addresses.
—PAT allows multiple private addresses to share one public address.
- like what is at work.
What subnets are set aside for private IP addressing?
- x.x.x
- 16.x.x - 172.31.x.x
- 168.x.x
What does POTS stand for?
Plain old telephone system.
Type of circuit switching technology for WAN.
What does PSTN stand for?
Public Service Telephone Network. Type of circuit switching for WAN.
What does ISDN stand for ?
DSL. It is a type of circuit switching for WAN.
Uses the same lines as phone lines.
What kind of packet switching do cable modems use?
MPLS (multi-protocol labeled switching)
Purely layer 3 technology
How does VOIP work?
It converts analog to digital through use of telephony adapters or smartphones.
Not designed to be secure.
Greatest threat is eavesdropping.
What are the security threats to wireless APs?
Unauthorized access
Sniffing data
War driving
Unauthorized access points.
What is the weakest transmission encryption?
WEP - wired equivalent privacy.
Describe WEP
It has a weak initialization vector (IV)
IV transmitted in plain text
Uses RC-4 stream cipher
Only option for 802.11b
Describe WPA
Wireless protected access
Introduced TKIP
Still uses RC-4
Describe WPA2
Wireless Protected Access 2
Introduced AES
Is not backwards compatible with WPA.
What are the three main flavors of cloud computing?
Software as a service
Platform as a service
Infrastructure as a service
What are the different types of cloud networks?
- Private
- Public
- Community
- Hybrid (public and private)
