questions and answers 2026\2027 A+
Grade
Inside local address
- correct answer The IP address assigned to a host on the inside network.
When the lease time start for DHCP
- correct answer After the DHCPAck is sent.
If you can ping 127.0.0.1 in your computer, what does it mean?
- correct answer 127.0.0.1 is the loopback address
TCP/IP is installed properly in your computer
Command to bind VLAN to port
- correct answer switchport access vlan 1
Command to configure trunk port
- correct answer switchport trunk encapsulation dot1q
switchport mode trunk
switchport trunk allowed vlan 1
switchport trunk allowed add vlan 114
Inside global address
- correct answer A valid public address that host on the inside network is assigned as it exits the router
Outside Global address
- correct answer A reachable IP address assigned to a host on internet.
,In a home network where it has a pc, a router, and a web server, pc has an address of 192.168.1.10,
which is what address?
- correct answer Inside local address
In a network where it has a pc, a router, and a web server, a router has an address of 200.200.200.1.
When a PC trying to send a packet to the internet, it uses router's address, which is what address?
- correct answer Inside global address
IPv4 Characteristics
- correct answer Connectionless: data is transmitted to other hosts without prior arrangement, UDP is
also connectionless.
Best-effort delivery: A network in which the network doesn't provide any guarantee that the data is
delivered or the quality of data.
Media independent: Operates independently of the medium carrying the data. However, it's concerned
with MTU.
Defined by RFC 791
In a home network where it has a pc, a router, and a web server, a webserver has an address of
100.100.100.1, which is what address
- correct answer It's an outside global address.
Describe NAT (network address translation)
- correct answer When a packet is sent out to from local network, a public address is assigned to this
packet, usually is the address of the router.
Describe PAT (Port address translation)
- correct answer When two machines in the local network want to access the services on public
network, port will be added to the inside global IP add to identify machines.
, Next available port
- correct answer What if two local machines use the same port number to access a web service? Router
will use next available function.
if two machines, one with IP 192.168.1.10 and one with 192.168.1.11 both use port 100 to access
google. The router will with an add of 200.200.200.1 will likely use 200.200.200.1:100 for .10 machine
and 200.200.200.1:101 for .11 machine. During this process, inside local machine's service port will not
be changed.
When a packet is sent, what sender doesn't know? And what receiver doesn't know?
- correct answer Sender doesn't know if the receiver is present
if the packet arrives
if the receiver can read the packet
receiver doesn't know when it is coming.
Gateway
- correct answer The address of the router interface
Network portion needs to be on the same network as all of the hosts
eg:
Host: 192.168.1.2/24
Gateway: 192.168.1.254/24
Address Resolution Protocol (ARP)
- correct answer Map a IP add to a MAC address
3 approaches of IP subnetting
- correct answer Classes: 2layer hierarchy
Fixed-length subnetwork mask: 3 layer hierarchy
Non-fixed-length subnetwork mask: n layer hierarchy
VLSM