Day 23 - DHCP & DNS Flashcards
When a DHCPv4-configured device boots up or connects to the network, the client broadcasts what type of message?
DHCPDISCOVER broadcast message
After a DHCP client sends a DHCPDISCOVER broadcast message, what does the DHCP server respond with?
DHCPOFFER unicast message
After a DHCP server sends a DHCPOFFER unicast message, what does the DHCP client respond with?
DHCPREQUEST broadcast message
After the DHCP client sends the DHCPREQUEST broadcast message, what does the DHCP server respond with?
DHCPACK
If a client is powered down or taken off the network, the IP address given by DHCP is what?
Returned to the pool for reuse
In what ways can a Cisco router be involved with DHCP
As a DHCP server
A DHCP relay agent
A DHCP client
What are the commands to configure a Cisco DHCP server to hand out ip addresses?
ip dhcp excluded-address {starting-ip-address} {ending-ip-address}
ip dhcp pool {name-of-pool}
network {network-address} {subnet}
default-router {ip-address}
dns-server {ip-address}
What command would you check to see if DHCP for a Router is being used a DHCP client?
show dhcp lease
What commands would you use on a Router to set it up as a DHCP client?
int {int}
-outside facing interface to the ISP
ip address dhcp
no shutdown
What command would you use to disable DHCP service on a device?
no service dhcp
What command would you use to verify DHCPv4 operation?
show ip dhcp binding
On a DHCP client, how would you release and renew DHCP configurations?
ipconfig /release
ipconfig /renew
To ensure that broadcasted DHCPDISCOVER messages are sent to the remote DHCPv4 server, what command would you use on a Cisco device?
ip helper-address
How many UDP services does the ip helper-address command forward?
8
What services does the ip helper-address command forward?
Port 37: Time
Port 49: TACACS
Port 53: DNS
Port 67: DHCP/BOOTP Server
Port 68: DHCP/BOOTP Client
Port 69: TFTP
Port 137: NetBios name service
Port 138: NetBios datagram service
How would you specify additional protocols other than DHCP to be forwarded by the ip helper-address command?
ip forward-protocol udp {port-number} {protocol}
IPv6 has two methods for obtaining a global unicast address. What are they?
SLAAC (Stateless address autoconfiguration)
Stateful DHCPv6
This method of obtaining an IPv6 address uses ICMPv6 Router Solicitation and Router Advertisement messages to provide addressing and other configuration information
SLAAC
When a client is configured to obtain its addressing information automatically using SLAAC, the client sends a __________ __________ __________ to the router. This message is then sent to the IPv6 all-routers __________ __________
Router Solicitation message
Multicast address
An IPv6 DHCP client uses this type of Neighbor Discovery protocol message to create its own IP address
Router advertisement (RA)
This type of message is normally used to learn the data link layer address of a neighbor on the same network
Neighbor Solicitation message
What type of message informs a client how to obtain automatic IPv6 addressing?
Router Advertisement message
To configure a router as a stateless DHCP server, you need to make sure what is enabled?
ipv6 unicast-routing
What are some types of record address for DNS?
A
NS
AAAA
MX
What does URI stand for?
Uniform resource identifier
What command would you use on a MacOS or Linux client to verify network information such as gateway address, IP address, etc.
ifconfig
With IPv6 SLAAC, routers respond to RS messages with what?
Router advertisements
