Net + Mod 6 Implementing Network Services Flashcards

Question 1

Q

Transport Layer Ports and Connections

Mod 6.1 Transport and Application Layer Protocols
Objectives 1.4 | 5.5

Answer

A

Layer 4 - delivery of multiplexed application data

Question 2

Q

Transmission Control Protocol (TCP)

Mod 6.1 Transport and Application Layer Protocols
Objectives 1.4 | 5.5

Answer

A

Works at the Transport layer to provide connection-oriented, guaranteed communication using acknowledgments to ensure that delivery has occurred
TCP takes data from the Application layer as a stream of bytes and divides it up into segments, each of which is given a header

Question 3

Q

TCP Handshake and Teardown

Mod 6.1 Transport and Application Layer Protocols
Objectives 1.4 | 5.5

Answer

A

Multiple TCP connections opened with the server is Handshake transaction = TCP flags
TCP Flags: Field in the header of a TCP segment designating the connection state, such as SYN(sync), ACK(acknowledge), or FIN(finshed)
To close a connection, also referred to as teardown

Question 4

Q

User Datagram Protocol

Mod 6.1 Transport and Application Layer Protocols
Objectives 1.4 | 5.5

Answer

A

Connectionless, nonguaranteed method of communication with no acknowledgments or flow control
The header size is 8 bytes, compared to 20 bytes (or more) for TCP

Question 5

Q

Netstat command Windows

Mod 6.1 Transport and Application Layer Protocols
Objectives 1.4 | 5.5

Answer

A

netstat - allows you to check the state of ports on the local host
- service misconfigurations
- identify suspicious remote connections on local host or remote IP address

(-p) switch with the protocol type
(-o) process ID (PID) number that has opened the port
(-b) process name
(-p) show the PID and process name
(-s) reports per protocol statistics, packets received, errors, discards, unknown requests, port requests, failed connections
(-e) Ethernet statistics

Question 6

Q

Common TCP and UDP Ports

Mod 6.1 Transport and Application Layer Protocols
Objectives 1.4 | 5.5

Answer

A

Look at book 6.1.6

Question 7

Q

Netstat command LINUX

Mod 6.1 Transport and Application Layer Protocols
Objectives 1.4 | 5.5

Answer

A

netstat:
- (-t) TCP
- (-u) UDP
- (-w) raw connections
- (-x) UNIX sockets/local server ports
- (-a) ports in the listening state in the output
- (-l(L)) only ports in the listening state, omitting established connections
- (-n) displays ports and addresses in numerical format
- (-4, -6) IPv4, IPv6
- (-I(i)) Ethernet statistics
- (-r) displays the routing table

Question 8

Q

DHCP

Mod 6.2 Dynamic Host Configuration Protocol
Objectives 1.4 | 3.4

Answer

A

automatic method for allocating an IP address, subnet mask, and optional parameters, such as the default gateway and DNS server addresses, when a host joins the network

4 Step
- Discover
- Offer
- Request
- Ack

Question 9

Q

DHCP Server Configuration

Mod 6.2 Dynamic Host Configuration Protocol
Objectives 1.4 | 3.4

Answer

A

DHCP server must be allocated a static IP address and configured with a range (or pool) of IP addresses and subnet masks plus option values to allocate
A range of addresses and options configured for a single subnet is referred to as a scope, start and end IP address along with a subnet mask

Question 10

Q

DHCP Options

Mod 6.2 Dynamic Host Configuration Protocol
Objectives 1.4 | 3.4

Answer

A

Lease Time
- T1 Timer: renew the lease when at least half the lease’s period
- T2 Timer: DHCP server does not respond, client attempts to rebind the same lease configuration with any available DHCP server

DHCP Options: DHCP configuration that assigns additional parameters, such as DNS server addresses. In DHCPv4, an option is used to identify the default gateway address
- default gateway
- ip address(es)
- DNS suffix domain name
- synchronization (NTP), file transfer (TFTP), VoIP proxy

Question 11

Q

DHCP Reservations & Exclusions

Mod 6.2 Dynamic Host Configuration Protocol
Objectives 1.4 | 3.4

Answer

A

Static assignments: uses IP address outside of DHCP scope
- lose the advantages of centralized configuration management

Reservations: mapping of a MAC address or interface ID to a specific IP address within the DHCP server’s address pool (static/fixed)
- automatically allocated reservation: refers to address leased permanently

Question 12

Q

Automatic Private IP Addressing

Mod 6.3 APIPA and SLAAC
Objectives 1.7 | 3.4

Answer

A

Automatic Private IP Addressing (APIPA) 169.254: cannot contact a DHCP server to revert to using an address from the range 169.254.x.y local link address

Question 13

Q

IPv6 Interface Autoconfiguration and Testing

Mod 6.3 APIPA and SLAAC
Objectives 1.7 | 3.4

Answer

A

IPv6, an interface must always be configured with a link local address
IPv4, you can either assign a routable IPv6 address statically or use an automatic addressing scheme

Neighbor Discovery (ND) Protocol: performs some of the functions on an IPv6 network that ARP and ICMP perform under IPv4
- Address autoconfiguration

Prefix discovery: Enables a host to discover the known network prefixes that have been allocated to the local segment
- Prefix discovery uses router solicitation (RS)
- router advertisement (RA) messages (Packet sent by an IPv6-capable router to notify hosts about prefixes and autoconfiguration methods available on the local link)
Local Address resolution: Allows a host to discover other nodes and routers on the local network (neighbors)
- uses neighbor solicitation (NS) and neighbor advertisement (NA) messages

Question 14

Q

IPv6 Interface Autoconfiguration and Testing

Mod 6.3 APIPA and SLAAC
Objectives 1.7 | 3.4

Answer

A

Stateless Address Autoconfiguration: used by IPv6, IPv4 uses link local addressing
- Mechanism used in IPv6 for hosts to assign addresses to interfaces without requiring manual intervention
- Host generates a link local address and uses Neighbor Discovery (ND) messages to test that it is unique
- host listens for a router advertisement (RA) or transmits a router solicitation (RS) using ND protocol messaging
- router can either provide a network prefix
- direct the host to a DHCPv6 server to perform stateful autoconfiguration
- perform some combination of stateless and stateful configuration

Question 15

Q

IPv6 Interface Autoconfiguration and Testing

Mod 6.3 APIPA and SLAAC
Objectives 1.7 | 3.4

Answer

A

ICMPv6

Error messaging: ICMPv6 supports the same sort of destination unreachable and time exceeded messaging as ICMPv4, Packet Too Big class of error, routers are no longer responsible for packet fragmentation and reassembly

Informational messaging: supports ICMPv4 functions, such as echo and redirect, plus a whole new class of messages designed to support ND(Neighbor Discovery) and MLD(Multicast Listener Discovery)

Question 16

Q

DHCPv6 Server Configuration

Mod 6.3 APIPA and SLAAC
Objectives 1.7 | 3.4

Answer

Study These Flashcards

A

DHCPv6 Server Configuration: DHCPv6 is often just used to provide additional option settings, rather than leases for host IP addresses

IPv6 does not support broadcast, clients use the multicast address ff02::1:2

Port 546 (clients)
Port 547 (servers)

Question 17

Q

DHCPv6 Server Configuration

Mod 6.3 APIPA and SLAAC
Objectives 1.7 | 3.4

Answer

Study These Flashcards

A

Stateless Mode Steps:
(1) NDP Router Solicitation
(2) NDP Router Advertisement
(3) DCHPv6 Solicit Message
(4) DHCPv6 Advertise Message
(5) DHCPv6 Information Request message
(6) DHCPv6 Reply Message

Stateful Mode Steps:
(1) NDP Router Solicitation
(2) NDP Router Advertisement
(3) DHCPv6 Solicit Message
(4) DHCPv6 Advertise Message
(5) DHCPv6 Information Request Message
(6) DHCPv6 Reply Message