Communication & Network Security Flashcards

1
Q

Decimal

A

10

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2
Q

Binary

A

2

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3
Q

Hex

A

16

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4
Q

Protocol

A

Agreed upon set of rules

Defines the format and order of messages and actions taken upon receipt of the message

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5
Q

Encapsulation

A

Layered model (OSI)

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6
Q

OSI Layer

A
Please Do No Throw Sausage Pizza Away (Bottom to Top)
Application
Presentation
Session
Transport
Network
Data link
Physical
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7
Q

Application Layer

A

interacts with applications to determine which network service will be required.

Layer 5-7 - considered Data Layers

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8
Q

Presentation Layer

A

data sent from one side of the connection is received Presenting data to application (Characters set/ graphics) in a way that makes sense

Layer 5-7 - considered Data Layers

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9
Q

Session Layer

A

establish and maintains connection between systems

Layer 5-7 - considered Data Layers

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10
Q

Transport Layer

A

ensure transmission end to end
handles sequencing of packets in transmission
Port/TCP & UDP headers

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11
Q

Network Layer

A

interaction network address schemes
How different network segment interact with each
other
IP Address/Routing

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12
Q

Data Link Layer

A
connects physical layer to network 
Ethernet address (MAC)/switches
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13
Q

Physical Layer

A

transmission across physical media

Bits 0/1

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14
Q

TCP/IP Model

A

Layer 5-7 (Application)
Layer 4 - Host to Host transport
Layer 3 - Internet
Layer 1-2 Network Access

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15
Q

TCP/IP Protocol Stack

A

Developed 1970, Darpa, DOD

OSI still referenced when talking about layers

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16
Q

IP4 Packets Diagram

A
32 bits across. Every 32 bit is 4 bytes. 
5 rows so total of 20 bytes
Starts at 0
Bits 0-31
Bytes 0-19
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17
Q

IP4 Class Address

A

Classless Inter-Domain Router (CIDR) (/8 notation)
Class A: /8 - 1.0.0.0 to 127.255.255.255
Class B: /16 - 128.0.0.0 to 191.255.255.255
Class C: /24 - 192.0.0.0 to 223.255.255.255
Class D: Multicast
Class E: Reserved

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18
Q

IP Broadcast

A
Limited broadcast (no router will block ) 255.255.255.255
Direct broadcast - 192.168.1.255 - Broadcast from 192.1.168.0 network
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19
Q

RFC-1918 (think of NAT)

A

Private addresses

  1. 0.0.0/8
  2. 16.0.0/16 - 172.31.0.0/16
  3. 168.0.0/16
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20
Q

Network Address Translation (NAT)

A

one to one -
Pool NAT - maps to a set of public addresses
Many to one - multiple mapped to one
NAT limitation 64k

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21
Q

gethostbyname

A

have fully qualified domain name (eric.sans.org) and need the address

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22
Q

gethostbyaddr

A

when you have address and the need the fully qualified domain name

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23
Q

DNS request & response

A

UDP if under 512 bytes

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24
Q

DNS Security issues

A

Not reliable

DNS Poisoning Attack

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25
Q

DNSSEC

A

does not provide confidentiality

digital signature for packet

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26
Q

Authenticated Denial of Existence (DNS)

A

Proving DNS record does not exist

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27
Q

IPv6

A

IPv4 - 32 bit 4.2 billion unique addresses
IPv6 - 128bit 340 undecillion addresses
Faster, no checksum like IPv4

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28
Q

IPv6 Features

A

route aggregation - method used to minimize the number of routing tables required in an IP network.
Support IPv6 tunneling over IPv4
Fixed header bytes - next header
Auto-configuration - don’t need to assign IP address

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29
Q

User Datagram Protocol (UDP)

A
Layer 4
connection less communication
don't care if the packet gets there
less overhead
Good if small amount of packet loss is acceptable
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30
Q

UDP Ports

A

DNS 53
NTP - 123
BootP - 67 & 68
SNMP - 161

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31
Q

Transmission Control Protocol

A

3 way handshake
SYN
SYN-ACK
ACK

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32
Q

TCP Header (Key fields)

A
Source Port
Destination Port
Sequence number
Acknowledgement number
SYN bit
ACK bit
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33
Q

TCP Ports

A
20 - FTP Data (receive)
21 - FTP - (send)
22 - SSH
23 - Telnet
25 - SNMP
53- DNS
79- Finger
80 - http
443 - https
source port >= 1024 (ephemeral)
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34
Q

TCP Code Bit (Flags)

A
Urg (Urgent)
Ack (Acknowledgement)
PSH (Push) - think of data stream
RST (Reset) - terminate connection
SYN(Synchronize)
FIN(Finish)
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35
Q

TCP Port Scanning (response types)

A

SYN/ACK - port is open and unfiltered
RST/ACT - port is closed and unfiltered
No response: Unknown

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36
Q

Socket Pair

A

Source IP Address
Source Port number
Destination IP Address
Destination Port Number

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37
Q

Internet Control Message Protocol (ICMP)

A
report error (troubleshoot) rather than transfer info
Ping & Traceroute are ICMP
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38
Q

TraceRoute

A

Set TTL to 1 and when router receives it, it will drop it.
Next iteration - TTL decreases for the one below it
Incrementing TTL for each hop

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39
Q

Secure Shell (SSH)

A

Port 22
Supports Authentication, compression, confidentiality, and integrity
Supports wide range of ciphers, 3DES, AES, Blowfish
SSH1 - Man In the middle attack

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40
Q

Secure Multipurpose Internet Mail Extension (S/MIME)

A

Secure MIME

Email

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41
Q

Simple Network Management Protocol (SNMP)

A
Monitoring of network devices 
SNMPv1 and SNMPv2 - clear text community string (NO CONFIDENTIALITY)
Public - read
Private - read & write
Should use SNMPv3 - port 161
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42
Q

Multilayer Protocols

A

TCP/IP - span multiple layers (OSI)

DNP3 (Distributed Network Protocol)

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43
Q

DNP3 (Distributed Network Protocol)

A
Open protocol smarts Smart Grid
SCADA
IEEE 1815- 2010
allowed pre-share key only
IEEE 1815 - 2012 current standard
Supports PK
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44
Q

Network Attached Storage (NAS)

A

Read/Write entire files

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45
Q

Storage Area Network (SAN)

A

block/clusters to files (not entire files like NAS)

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46
Q

Internet Small Computer System Interface (ISCSI)

A

network cables/routed via IP (NAS)
think of SCSI drives that are connected to network
Lun - logical grouping of drives

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47
Q

Fibre Channel

A

Sans Protocol

Does not use Ethernet/does not easily scale across WAN

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48
Q

Fibre Channel (FCoE)

A

Local subnet only

TCP/IP is not used - layer 2

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49
Q

Fibre Channel over IP (FCIP)

A

can route (layer 3)

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50
Q

Voice of IP (VOIP)

A
Digitized before sending across wire
Combining data
Cost-effective
Redundancy
Security issue (PBX)
Expsoures
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51
Q

PSTN PBX/VOIP

A

Common and phased approach

PBX and VOIP network

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52
Q

UP PBX/PSTN

A

must use VOIP phones

IP PBX - soft switch route calls

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53
Q

VOIP Components

A
Media Gateways
Registration & Location servers
Proxy Servers
Messaging Servers
End-User devices (VOIP Phones)
54
Q

VOIP Protocols

A

Signaling (H.323 SIP) - setup and tear down call, locate users, negotiate protocols
Media (RTP) - transport of package
Supporting (IP, TCP, UDP, etc..)

55
Q

SIP (H.323)

A

Setup and tear down of calls

56
Q

SIP

A

Plaintext
TCP/UPD
Looks like HTTP

57
Q

RTP

A

Transmit voice content between VOIP devices
Over plaintext
Commonly over UDP, can use TCP

58
Q

Virtual Network Computing (VNC)

A

TCP Port 5900

59
Q

Remote Desktop Sharing (RDP)

A

TCP Port 3389

60
Q

802.11 Standard

A

**Fundamental risk - no physical control of network
Supports two physical layers
Infrared
Radio Frequency

61
Q

802.11 Types

A
  1. 11b - 11 Mbps at 2.4 ghz
  2. 11a - 54 Mbps at 5 ghz
  3. 11g - 54 Mbps at 5 ghz
  4. 11n - 300 Mbps using both 2.4 & 5 ghz
  5. 11ac - 1.3 Gbps at 5 ghz
62
Q

802.11 Network modes

A

Managed - client connect to WAP
Master - Wireless Access point
Ad-hoc - peer to peer
Monitor Mode - ready only/sniffing

63
Q

Wire Equivalent Privacy (WEP)

A

Inability to rotate WEP keys

Permit recovery of WEP keys in minutes

64
Q

Types of Network

A
PAN - Personal area network (bluetooth)
LAN - Local Area Netwrk
CAN - Campus Area Network
MAN - Metropolitan Area nework
WAN- Wide Area Network
GAN - Global Area Network
65
Q

LAN transmission method

A

unicast - from source to single network destination
multicast - from source to multiple network destination
Broadcast - source to all network address

66
Q

Physical Topology

A

How systems are connected - bus, ring, star

67
Q

Logical Topology

A

rules of communication

Ethernet/ATM

68
Q

Persistent Carrier Sense

A

No ack from destination, assumes collision and re-sends immediately

69
Q

Non-Persistent Carrier Sense

A

no ack from destination, assume collision, waits a random amount of time before resending

70
Q

Carrier Sense Multiple Access with Collision Dectection (CSMA/CD)

A

Ethernet

Send/transmit simultaneously

71
Q

Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)

A

Wireless

72
Q

Polling

A

Only allowed to send when given permission

73
Q

T1

A

DS1 - 1.544 mbps

74
Q

T3

A

DS3 - 44.376 mbps

75
Q

E1

A

Wide Area Digital Transmission- 2.048 mbps (Europe)

76
Q

E3

A

Wire Are Digital Transmission - 34.368 mbps

77
Q

SDLC

A

Normal Response Mode - polling speak when given to speak
Asynchronous Response mode (ARM) - cannot transmit without permission from primary *Error recovery
Asynchronous Balance Mode (ABM)- equally responsibility

78
Q

ISDN

A

reuse analog line infrastructure for data
High cost/Low speed
2 64K channel - 128k

79
Q

Digital Subscriber Line (DSL)

A

Point to point use existing phone lines

Symmetrical & Asymmetrical (download faster than upload)

80
Q

Symmetric Digital Subscriber Line (SDSL)

A

Symmetrical up/download

1.544 (T1 equal)

81
Q

High bit rate Digital Subscriber Line (HDSL)

A

Symmetrical up/download

1.544 (T1 equal)

82
Q

Single Pair High Speed Digital Subscriber Line (SHDSL)

A

standardized version of symmetric DSL
replace SDSL & HDSL
Up to 5.696 Mbit/s

83
Q

Asymmetric Digital Digital Subscriber Line (ADSL)

A

ADSL 2 - 12 mbps/3.5

ADSL 2+ - 24 mbps/3.5

84
Q

Very High Speed Digital Subscriber Line (VDSL)

A

VSDL 3 - 52 mbps/16 mbps
VDSL 4+ - interoperable with ADSL 2+
1600ft max

85
Q

Cable Modem

A

date rate - number of concurrent uesrs

1,000-4,500 ft

86
Q

X.25

A

built in error correction

Precursor to frame relay

87
Q

Asynchronous Transfer Mode (ATM)

A

Fixed cell size 48 bytes
Fixed header size 5 bytes
Total 53 bytes regardless of the size of the information each time.

88
Q

Multiprotocol Label Switching (MPLS)

A

First router - apply label

later router - only inspect label

89
Q

Modem

A

modulate binary data to be sent over analog network

demodulate analog data to digital binary

90
Q

CSU/DSU

A
converts LAN protocol to transfer over WAN
Circuit Closet (DMARC)
91
Q

DTE/DCE

A

Data Terminal Equipment (DTE) customer end of WAN - your router before ISP
Data Communications Equipment (DCE) ISP Network - ISP Router

92
Q

Repeaters

A

Layer 1
Signal deteriorate with distance
recreate signal before retransmitting

93
Q

Hubs

A

Layer 1
Operate as multiport repeater
No Security

94
Q

Bridges

A

Layer 2
Multiple devices to connect to one bridge port
Learn MAC of each systems
Does not forward traffic unless necessary

95
Q

Switch

A

Layer 2
Learns MAC address
Provides physical and logical separation

96
Q

VLANS

A

different VLAN will not see each other broadcast

97
Q

Routers

A

Routing Tables - routing information that points to all reachable network

98
Q

Firewall Types

A

Packet Filtering
Stateful - remember state information - matching request allowed in
Proxy -
Next Generation Firewalls (NGFW) - payload

99
Q

Coaxial

A

50 ohm - digital signaling
75 ohm cable for high speed data & analog signal
Baseband - Single channel
Broadband - multiple channel

100
Q

Fiber Optic Cable

A

resistance to electromagnetic interference

101
Q

Crossover Cable

A

+Tx to + Rx

-Tx to -Rx

102
Q

Category for twisted Pair

A
Cat 1 - telephone
Cat 2 - < 4 mbps
Cat 3 -  10 mbps
Cat 4 - 16 mbps
Cat 5 - 100 mbps
Cat 6 - 1000 mbps
103
Q

Analog Signal

A

continuous signal

104
Q

Digital Signal

A

pulses signal

105
Q

Asynchronous Communications

A

Not tied to a clock
Send start bit
Send stop bit

106
Q

Synchronous Communications

A

Tied to clock

Don’t need to send start & stop bit

107
Q

MAC address

A

48 bit, 12 hexadecimal

First 24 bit are organizationally unique identifier

108
Q

Routing Information Protocol (RIP)

A

Legacy
Based on hop count - shortest
Maximum 15 hops
Routing updates every 30 seconds

109
Q

Distance Vector

A

identify neighbors and figures out distances metrics to each.

110
Q

Open Shortest Path First

A

routers knows all the paths

factoring in # of hops and bandwidth

111
Q

Border Gateway Protocol (BGP)

A

Used by the Internet

112
Q

Interautonomous system routing

A

two or more BGP in different systems

113
Q

Intra-autonomous system routing

A

two or more BGP in same systems

114
Q

Pass-Through autonomous system routing

A

two or more BGP across autonomous systems without question

Extranet routing

115
Q

Autonomous System

A

route to the organization, not network.

Multiple routes - send to the closest/fastest one

116
Q

Software Defined Network (SDN)

A

Takes routing decision and gives it to server

Router just route, no decision to be made

117
Q

VPN Security Issue

A

Bypass firewall, IDES’s, virus scanner, web filter

Trusting the “other end “

118
Q

IPSEC

A

IETF - RFC 2401

119
Q

IPSEC Modes

A

Tunnel - sender to receiver (1 set of system) - don’t know the sender or receiver
Transport - sender encrypt, received decrypts

120
Q

TACAS Authentication

A

Start - continue - reply

Single Factor Authentication

121
Q

Extensible Authentication Protocol (EAP)

A

RFC-2284

AuthN Mechanism

122
Q

EAP-MD5

A

Client to Server
Weakest
Only one way authentication

123
Q

EAP-TLS

A

PKI (Client cert) on both server and client

Secure TSL tunnel for authN

124
Q

EAP-TTLS

A

Can pre-shared key or password

125
Q

PEAP

A

Cisco, Microsoft, RSA
Similar to EAP-TTLS
Not requiring 3rd party cert

126
Q

802.1X

A

No IP until you authenticate

127
Q

Supplicant

A

Software to authenticate 802.1x via Layer 2

128
Q

Authenticator

A

WAP - open/close port based on authentication

129
Q

Authentication Server

A

Diameter or Radius to user DB

130
Q

NAC

A

Health Check
Patches/AntiVirus up to date
Client pass - access is granted
Client failed - place in isolated vlan