Comptia Network+ (N10-006) Part 4: Making Tcp/ip Work

Front 1

What are the steps of a TCP three-way handshake?

Back 1

Client sends SYN.

Server sends SYN ACK.

Client sends ACK.

Hint 1

Synchronize acknowledgement

Front 2

What are the steps to closing a TCP session?

Back 2

Client sends FIN.

Server sends FIN ACK.

Client sends ACK.

Hint 2

Finish acknowledgement

Front 3

What are the advantages/disadvantages of TCP and UDP?

Back 3

TCP is connection oriented, allowing for detection of lost packets.

UDP is connectionless, used when speed is more important than reliability - DHCP, e.g.

Front 4

What comprises a TCP Segment?

Back 4

Originating and destination port numbers; sequence number; ACK; data packet.

Front 5

What comprises a UDP Datagram?

Back 5

Originating and destination port numbers; data length; checksum; data packet.

Front 6

What is ICMP and how is it used?

Back 6

Internet Control Message Protocol. Works at the Internet layer of the TCP/IP model, used for quick communications - Ping, ARP, e.g.

Front 7

What is IGMP, and how is it used?

Back 7

Internet Group Management Protocol. Works at the Internet layer of the TCP/IP model. Used for creating multicasts, using 224.x.x.x IP addresses.

Front 8

What comprises an ICMP packet?

Back 8

Type value (Ping or ARP, e.g.); checksum.

Front 9

What comprises an IGMP packet?

Back 9

Type value; checksum; Group Address (224.x.x.x); Source Address (originating server IP).

Front 10

What is Wireshark?

Back 10

Packet/protocol analyzer

Front 11

What is netstat?

Back 11

Lists all open ports and connections on the local computer.

Front 12

What are some of the different switches for netstat and their purposes?

Back 12

-n: displays info in numerical form

-b: displays executable involved in connection

-o: displays process ID for connection

-a: displays all active ports, irrelevant of connection

-r: displays local routing table (same as 'route print')

Front 13

What are the particulars of HTTP?

Back 13

Hyper Text Transfer Protocol, used for Internet traffic. Uses port 80. No encryption.

Front 14

What are the particulars of HTTPS?

Back 14

HTTP with security (encryption). Uses port 443. Encrypts web data being transferred between server and client.

Front 15

What are the two most popular web server types?

Back 15

Microsoft's IIS (Internet Information Service) and Apache (open source).

Front 16

What are the particulars of FTP?

Back 16

File Transfer Protocol. Used to transfer files over the Internet. Uses ports 21 (outgoing) and 20 (incoming). No encryption.

Front 17

What is the purpose of an anonymous account on an FTP server?

Back 17

Allows users without accounts on the system to download files.

Front 18

What are three ways to access an FTP server?

Back 18

Third-party FTP client; web browser (using FTP:// in Address field); command prompt (ftp command).

Front 19

What are common commands when using FTP at a command prompt?

Back 19

Open (connect to a server)

Put (upload a file)

Get (download a file)

Disconnect (end a server session)

Front 20

What is the secure version of FTP?

Back 20

SFTP, using SSL and TLS.

Front 21

What is TFTP?

Back 21

Trivial FTP. Uses UDP, on port 69. Requires TFTP server and client software.

Front 22

What protocol is used to send email in a server-client environment?

Back 22

SMTP - Simple Mail Transfer Protocol, using TCP port 25.

Front 23

What protocols are used to receive mail?

Back 23

-POP3 (Post Office Protocol v3), using TCP port 110.

-IMAP4 (Internet Message Access Protocol v4), using TCP port 143.

Front 24

What is required when configuring an email client?

Back 24

SMTP and POP3 or IMAP settings.

Front 25

What's the basic difference between POP and IMAP?

Back 25

IMAP allows for organization (folders, e.g.) on the server; POP handles this on the client only, meaning that any changes made on one client will not replicate to another on a different computer.

Front 26

What is Telnet?

Back 26

Remote server-client software via command prompt, using TCP port 23. No encryption, but requires login credentials.

Front 27

What is SSH?

Back 27

Secure Shell. Encrypted version of Telnet, using TCP port 22.

Front 28

What is rlogin?

Back 28

An old remote server-client software, using no encryption nor login credentials.

Front 29

What is DNS?

Back 29

Domain Name System. DNS servers resolve IP addresses based off of FQDNs (Fully Qualified Domain Names).

Front 30

What are the components of a FQDN?

Back 30

-At the right, the top-level domain. (com, e.g.)

-At the left, the computer name. (www, e.g.)

-In between, the secondary domain. (google, e.g.)

Front 31

What are the limits of a FQDN?

Back 31

127 individual names (including top-level and computer); 256 characters.

Front 32

What two tasks do DNS servers perform?

Back 32

Create and respond to DNS queries. (Workstations do not create DNS queries.)

Front 33

What steps go into retrieving an IP address for an Internet FQDN?

Back 33

-Client computer requests IP from local DNS server.

-DNS server uses Root Hints list to query a Root DNS Server.

-Root DNS server responds with the IP for the top-level domain DNS server.

-TLD DNS server responds with the IP for the secondary domainDNS server.

-SD DNS server responds with the IP for the original request.

Front 34

What are forward lookup zones (FLZ) when relating to DNS?

Back 34

Used to resolve FQDNs to IP addresses.

Front 35

What are reverse lookup zones (RLZ) when relating to DNS?

Back 35

Used to resolve IP addresses to FQDNs.

Front 36

What is a Start of Authority (SOA) FLZ DNS record?

Back 36

The authoritative name server for a domain, or the primary DNS server. Only one per domain.

Front 37

What is a Name Server (NS) FLZ DNS record?

Back 37

Provides quick FQDN to IP address resolution. Several allowed per domain.

Front 38

What are host FLZ DNS records?

Back 38

Individual computer names on the domain.

Front 39

What's the difference between A and AAAA host records?

Back 39

A is IPv4; AAAA is IPv6.

Front 40

What is an alias host record, and what's another name for it?

Back 40

Used for a secondary name for a server. (Fileserver vs. FS01, e.g.)

CNAME, or canonical name.

Front 41

What is a Mail Exchanger (MX) DNS record?

Back 41

Directs mail to the mail server in the domain.

Front 42

What is a Service Location (SRV) DNS record?

Back 42

Directs to a particular service - FTP or Telnet, e.g.

Front 43

What is the purpose of the HOSTS file?

Back 43

Contains IP addresses and their associated FQDNs. Pre-dates and takes precedence over DNS.

Front 44

What is NBTSTAT and some of its switches?

Back 44

NetBIOS over IP.

-c Show NBT cache of namessand IPs.

-s Show sessions (current connections).

Front 45

What is DDNS?

Back 45

Dynamic DNS. Assigns a FQDN to a DHCP-assigned (changeable) external IP address.

Front 46

What's the fastest way to test for a DNS issue?

Back 46

Try accessing via IP address rather than FQDN. If reachable, DNS is the issue.

Front 47

What is NSLOOKUP?

Back 47

Name Saver Lookup. Used to see default DNS server information. Use 'server [IP address]' to verify DNS addresses.

Front 48

What is DIG?

Back 48

Domain Information Groper. (Third-party tool.)

Front 49

What two components are required to encrypt cleartext to cyphertext?

Back 49

An algorithm and a key.

Front 50

What is symmetric encryption?

Back 50

An algorithm that uses the same key to encrypt and decrypt data.

Front 51

What is asymmetric encryption?

Back 51

Requires a public key (shared between both ends of the encrypted conversation, and used to encrypt) and a private key (used only to decrypt).

Front 52

What is a hash?

Back 52

A one-way, fixed-length encryption, often used for data verification. Common hashes are MD5 and SHA-1.

Front 53

What's the difference between authentication vs. authorization?

Back 53

Authentication is the confirmation - access credentials, e.g.

Authorization controls what resources can be accessed with those credentials.

Front 54

What are the three types of access controls?

Back 54

-Mandatory Access Control, using labels which define access.

-Discretionary Access Control, allowing individualized access.

-Role-based Access Control, using groups to define access.

Front 55

What is RADIUS?

Back 55

A form of AAA - Authentication/Authorization/Accountability - system, using a server, client, and supplicant, and database. (The supplicant - a laptop, e.g., requests authentication from the client.)

Front 56

What ports are utilized by RADIUS?

Back 56

UDP 1812-1813 or 1645-1646

Front 57

What is TACACS+?

Back 57

A Cisco proprietary AAA system, using a server, client (router, e.g.), and user. Uses TCP port 49.

Front 58

What are the components of Kerberos?

Back 58

A Windows domain controller (which automatically becomes a Kerberos Key Distribution Center, which is also an Authentication Server and a Ticket Granting Service) and a client workstation.

Front 59

What happens during a Kerberos authentication process?

Back 59

Client sends hashed credentials; authentication server sends a Ticket Granting Ticket (TGT) to client (granting authentication). TGT is time-stamped and sent back to Ticket Granting Service, which time-stamps the TGT again, making it a Token. The Token is used for accessing domain resources.

Front 60

What is a drawback for Kerberos?

Back 60

Relies heavily on timestamps, therefore works best on wired networks.

Front 61

What is EAP?

Back 61

Extensible Authentication Protocol. Used to store several different types of AAA protocols, but can't be used with Kerberos. Used most frequently with wireless connectivity.

Front 62

What are some of the different types of EAP?

Back 62

-EAP PSK (Personal Shared Key)

-EAP PEAP (Password Encrypted Authentication Protocol, i.e. credentials)

-EAP MD5 (hashes)

-EAP TLS (single certificate)

-EAP TTLS (multiple certificates)

Front 63

What is the purpose of tunneling?

Back 63

Used to encrypt data from unencrypted protocols - FTP through SSH, e.g.

Hint 63

Secrets

Front 64

What is NTP?

Back 64

Network Time Protocol, running on port 123, used for precise timing for programs requiring time functions - Kerberos, e.g.