Questions and Answers
What does the 'A' flag in a Router Advertisement (RA) message indicate?
Which multicast address does R1 use to send Router Advertisement (RA) messages to all nodes?
What information does the RA message include when the 'O' and 'M' flags are set to 0?
What is the purpose of Router Solicitation (RS) messages?
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Which command can be used to verify if R1 has joined the IPv6 all-routers group?
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What is the frequency of RA messages sent by R1?
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What must a host do to generate an IPv6 Global Unicast Address (GUA) using SLAAC?
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Which IPv6 multicast address does the IPv6 all-routers group respond to?
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What triggers a router to send a Router Advertisements (RA) message?
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Which method does SLAAC utilize to generate a host's 64-bit IPv6 interface identifier (ID)?
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How does SLAAC interact with DHCPv6 when obtaining an IPv6 address?
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What is the role of the Router Solicitation (RS) message in the SLAAC process?
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How frequently does a router send Router Advertisements (RAs) if no RS messages are received from hosts?
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What does the O flag set to 1 in a Router Advertisement (RA) message indicate?
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If a client receives a stateless RA message, what action does it take?
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Which command is used to enable Stateless DHCPv6 on an interface?
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What is the primary purpose of a stateful DHCPv6 operation?
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How does the DHCPv6 server interact in a stateless configuration?
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What information is typically contained in a stateless RA message?
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What UDP port is used by DHCPv6 messages sent from the client to the server?
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What default value does the M flag have in a stateless RA message?
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What is a key feature of the Router Solicitation (RS) process?
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What happens if the O flag is set to 0 in the RA?
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What does the A flag in an RA message signify?
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Which flag in the RA message indicates that a stateful DHCPv6 server should be used?
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What is the primary function of SLAAC in an IPv6 network?
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How frequently does SLAAC send periodic ICMPv6 RA messages?
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What scenario would lead to a host using the O flag from an RA message?
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Which of the following best describes the nature of SLAAC?
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Which of the following flags must be unselected to indicate that SLAAC is not being used?
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In a network with no DHCPv6 server, which method allows hosts to configure their IPv6 addresses?
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What does the A flag set to 1 in an RA message indicate to the client?
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How often does a router send RA messages by default?
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If an RA message includes both the A and M flags, what does this indicate?
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What type of service does SLAAC represent in terms of address assignment?
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Which command is used to enable a router to send RA messages?
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What information does a host acquire from the RA message when using SLAAC?
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What do the O and M flags set to 0 in an RA message instruct the client to do?
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What is the purpose of the DAD process in SLAAC?
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Which method is NOT used by a host to generate its 64-bit interface identifier in SLAAC?
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What triggers a router to send an additional RA message?
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What does SLAAC stand for in the context of IPv6 configuration?
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When using SLAAC, how does a host check for uniqueness of its IPv6 GUA?
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Study Notes
SLAAC Overview
- Stateless Address Autoconfiguration (SLAAC) allows hosts to configure their own IPv6 global unicast addresses without needing a DHCPv6 server.
- SLAAC is stateless, meaning no server maintains addressing information.
- ICMPv6 Router Advertisement (RA) messages are sent periodically (every 200 seconds) to assist hosts in configuring their addresses.
Router Solicitation and Advertisement
- Hosts can send Router Solicitation (RS) messages to request Router Advertisement (RA) messages.
- RA messages contain address configuration information for hosts utilizing SLAAC.
- R1 configured with:
- Link-local address: fe80::1
- Global Unicast Address (GUA): 2001:db8:acad:1::1
- Subnet: 2001:db8:acad:1::/64
- IPv6 all-nodes multicast group: ff02::1
RA Message Flags
- Flags in RA messages inform hosts how to configure addressing:
- A flag (Autoconfiguration flag): Set to 1, indicates using SLAAC to create a GUA.
- O flag (Other Configuration flag): Set to 1, indicates additional configuration info is available from a stateless DHCPv6 server.
- M flag (Managed Address Configuration flag): Indicates the use of a stateful DHCPv6 server for obtaining a GUA.
Host Configuration Processes
- Hosts typically acquire a 64-bit IPv6 subnet from RA and generate a unique 64-bit interface identifier (ID) through:
- Random generation: Used by default in Windows 10.
- EUI-64 method: Uses the host's MAC address to create an interface ID; however, this raises privacy concerns.
Duplicate Address Detection (DAD)
- DAD ensures the generated GUA is unique through ICMPv6 Neighbor Solicitation (NS) messages.
- The solicited-node multicast address duplicates the last 24 bits of the host's IPv6 address.
Stateless DHCPv6
- When the RA indicates stateless DHCPv6, the host uses RA message information for addressing and contacts a DHCPv6 server for additional configurations.
- The DHCPv6 server provides configuration parameters but does not maintain IPv6 address bindings.
Stateful DHCPv6
- If the RA indicates stateful DHCPv6, the host relies solely on the DHCPv6 server for all configuration information.
Commands and Configuration
- To enable SLAAC, routers must join the IPv6 all-routers group using the "ipv6 unicast-routing" command.
- Use "show ipv6 interface" command to verify router settings.
- The command "ipv6 nd other-config-flag" sets the O flag to 1 for stateless DHCPv6; "no ipv6 nd other-config-flag" resets it to SLAAC only.
ICMPv6 Messages
- PC sends an RS message to the all-routers multicast address (ff02::2) to request an RA.
- The router replies with an RA message sent to the all-nodes multicast address (ff02::1), which the PC uses to configure its IPv6 settings.
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Description
Test your knowledge on the Stateless Address Autoconfiguration (SLAAC) process and its deployment options. This quiz will cover concepts such as Router Solicitation, Router Advertisement, and IPv6 addressing. Prepare to understand the workings of link-local and global unicast addresses.