10) Explaining Network Services Flashcards
Focuses on application protocols that perform low-level network operations tasks, such as providing dynamic address or name resolution services. You should understand the functions of the network services protocols and the ports that they rely upon to operate. a) Explain the use of network addressing services. b) Explain the use of name resolution services. c) Configure DNS services.
An administrator is configuring the TCP/IP settings in workstations and wants to use the solution with the least amount of overhead. What setting will the administrator select?
A. UDP
B. TCP
C. IP
D. DHCP
D. DHCP
The administrator will use Dynamic Host Configuration Protocol (DHCP) which provides an automatic method for allocating an IP address, subnet mask, and other optional parameters.
The User Datagram Protocol (UDP) works at the Transport layer, but unlike TCP, it is a connectionless, nonguaranteed method of communication with no acknowledgments or flow control.
The Transport Control Protocol (TCP) works at the Transport layer and is a connection-oriented, guaranteed method of communication with acknowledgments and flow control.
The Internet Protocol (IP) works at the Network layer and provides logical addressing and packet forwarding between different networks.
An administrator is configuring a DHCP server. What configurations must the administrator apply to the server? (Select all that apply.)
A. The server must receive a dynamic IP address
B. The administrator must configure the DHCPDISCOVER packet
C. The server must receive a static IP address
D. The administrator must configure a scope
C. The server must receive a static IP address
D. The administrator must configure a scope
An administrator must allocate a static address to the DHCP server as network services that always need to be on should always have static IP addresses.
An administrator must configure a scope or a range (or pool) of IP addresses and subnet masks plus option values to allocate.
An administrator should not allocate a dynamic address to a DHCP server as network services that always need to be on should always have static IP addresses.
When negotiating a DHCP connection, some hosts cannot receive unicast without an IP address. They should set a broadcast bit in the DHCPDISCOVER packet.
A client is attempting to renew its lease with the DHCP server so that it can keep the same IP addressing information. How much of the lease duration has lapsed?
A. At least 50%
B. At least 87.5%
C. At least 0
D. At least 255
A. At least 50%
A client can renew the lease when at least half the lease’s period has elapsed so that it keeps the same IP addressing information.
If the original DHCP server does not renew a client’s lease by the time 87.5% of the lease duration is up, the client will attempt to renew with any available DHCP Server.
DHCP options besides IP address and subnet mask have a tag byte or decimal value between 0 and 255, although the DHCP server cannot use 0 as an option value.
DHCP options besides IP address and subnet mask have a tag byte or decimal value between 0 and 255, although the DHCP server cannot use 255 as an option value.
An administrator is using DHCP and wants to retain centralized management of IP addressing but needs to ensure that specific devices that supply always-on functionality have static IP address assignments. What is the best solution?
A. Configure static assignments on those devices
B. Assign addresses from a specially configured exclusion range
C. Create reservations
D. Configure scopes
C. Create Reservations
To retain centralized management of IP addressing, the administrator can create a reservation which is a mapping of a MAC address or interface ID to a specific IP address within the DHCP server’s address pool.
The administrator can configure static assignments using IP addresses outside the DHCP scope; however, this does not allow the administrator to retain centralized management.
The administrator can assign IP addresses from a specially configured exclusion range; however, the administrator must statically assign them, and this does not allow the administrator to retain centralized management.
A scope is a range of IP addresses and options configured for a single subnet. Administrators define scopes by providing a start and end IP address along with a subnet mask.
An organization has multiple subnets but is only using one DHCP server. How is this possible? (Select all that apply.)
A. Stateless address autoconfiguration
B. Default gateway
C. DHCP relay
D. UDP forwarding
C. DHCP relay
D. UDP Forwarding
Administrators can configure a DHCP relay agent to provide forwarding of DHCP traffic between subnets to avoid provisioning and configuring DHCP servers on every subnet.
UDP forwarding is a more general application of a DHCP relay, but UDP forwarding forwards DHCP, the Network Time Protocol (NTP), and other broadcast-based applications.
In IPv6, the Stateless Address Autoconfiguration (SLAAC) process can locate routers (default gateways) and generate a host address with a suitable network prefix automatically.
A default gateway is the IP address of the router that allows devices on one subnet to communicate with devices on other subnets.
An administrator ran a command and determined that the FQDN of a client is forbes.sales.realty.com. What is the hostname of the client?
A. com
B. sales
C. forbes
D. realty
C. forbes
A fully qualified domain name (FQDN) consists of the hostname and a domain suffix. In this domain, forbes is the hostname and the domain suffix is sales.realty.com.
A fully qualified domain name (FQDN) consists of the hostname and a domain suffix. In this domain, the suffix .com is the top-level domain.
A fully qualified domain name (FQDN) consists of the hostname and a domain suffix. In this domain, sales is a domain name within the top-level domain .com.
A fully qualified domain name (FQDN) consists of the hostname and a domain suffix. In this domain, realty is a domain name within the top-level domain .com.
ICANN is a non-profit organization that’s dedicated to keeping the Internet secure. What does ICANN manage? (Select all that apply.)
A. Country codes
B. Generic TLDs
C. FQDNs
D. DNS
B. Generic TLDs
D. DNS
ICANN (Internet Corporation for Assigned Names and Numbers) manages the generic TLDs (top level domains) such as .com, .org, .net, .info, and .biz.
ICANN manages the Domain Name System (DNS) which is a global hierarchy of distributed name server databases that contain information on domains and hosts within those domains.
Organizations appointed by the relevant government generally manage country codes such as .uk, .ca, and .de.
Organizations must register a domain name with a registrar to ensure that it is unique, but the organization that registered the domain name manages its FQDNs (fully qualified domain names).
A user has typed www.network.com into a web browser. The domain name server cannot resolve the name, so it is querying other name servers to try to find it. What kind of lookup is the domain name server performing?
A. Iterative
B. Recursive
C. Start of authority
D. Resource record
B. Recursive
A recursive lookup means that if the queried server is not authoritative, it does take on the task of querying other name servers until it finds the requested record or times out.
In an iterative lookup, a name server responds to a query with either the requested record or the address of a name server at a lower level in the hierarchy that is authoritative for the namespace.
The Start of Authority (SOA) record identifies the primary authoritative name server that maintains complete resource records for a zone.
Resource records allow a DNS name server to resolve queries for names and services hosted in the domain into IP addresses.
An organization is using IPv4 addresses. Which of the following records will resolve a hostname to the IP address?
A. A
B. AAAA
C. CNAME
D. Alias
A. A
Administrators use an address (A) record in the domain name system to resolve a hostname to an IPv4 address using the UDP transport protocol over port 53 by default.
Administrators use an AAAA record in the domain name system to resolve a hostname to an IPv6 address. Due to the large address sizes of IPv6, AAAA records can exceed the maximum UDP packet size.
A Canonical Name (CNAME), or alias record, configures an alias for an existing address record (A or AAAA). An administrator can redirect an alias to a completely different host if needed.
An alias record, or Canonical Name (CNAME) record, configures an alias for an existing address record (A or AAAA).
An administrator configures a new mail server to meet the organization’s goals. Which record lists the IP addresses or names of servers that can send email from a particular domain and combats the sending of spam?
A. SPF
B. SRV
C. TXT
D. MX
A. SPF
A Sender Policy Framework (SPF) record lists the IP addresses or names of servers that can send email from a particular domain and combats the sending of spam.
A Service (SRV) record contains the service name and port for a particular application. SRV records often locate VoIP or media servers.
A text record (TXT) stores any free-form text that may support other network services. A single domain name may have many TXT records.
A Mail Exchange (MX) record identifies an email server for the domain. The host identified in an MX record must have an associated A or AAAA record. A MX record must not point to a CNAME record.
An organization is using IPv4 addresses. Which of the following records will resolve a hostname to the IP address?
A. A
B. AAAA
C. CNAME
D. Alias
A. A
Administrators use an address (A) record in the domain name system to resolve a hostname to an IPv4 address using the UDP transport protocol over port 53 by default.
Administrators use an AAAA record in the domain name system to resolve a hostname to an IPv6 address. Due to the large address sizes of IPv6, AAAA records can exceed the maximum UDP packet size.
A Canonical Name (CNAME), or alias record, configures an alias for an existing address record (A or AAAA). An administrator can redirect an alias to a completely different host if needed.
An alias record, or Canonical Name (CNAME) record, configures an alias for an existing address record (A or AAAA).
