8: DHCPv6 (Dynamic Host
Configuration Protocol for IPv6)
Rick Graziani
Cabrillo College
Rick.Graziani@cabrillo.edu
For more information please check out my Cisco Press book and video series:
IPv6 Fundamentals: A Straightforward
Approach to Understanding IPv6
•
By Rick Graziani
•
ISBN-10: 1-58714-313-5
IPv6 Fundamentals LiveLessons: A
Straightforward Approach to Understanding IPv6
•
By Rick Graziani
•
ISBN-10: 1-58720-457-6
©
8.1: Router Advertisement and DHCPv6
DHCPv6
Global Unicast
Manual
Dynamic
Stateless
Static
IPv6
unnumbered
Stateful
SLAAC
DHCPv6
SLAAC +
DHCPv6
DHCPv6-PD
Similar to IPv4 unnumbered
Static + EUI 64
©
Dynamic IPv4 Address Allocation
I need an IPv4 addressing
information from a DHCP server.
DHCP Server
DHCP Client
Here is your IPv4
address, subnet mask,
default gateway and
DNS server addresses.
©
All Dynamic Addressing Begins with
the RA Message
ICMPv6 Router Advertisement
ICMPv6 Router Solicitation
Multicast: To all
IPv6 routers, I need
IPv6 address
information
DHCPv6
Server
Multicast: To all
IPv6 devices,
I might not even be
let me tell you how
needed. 
to do this …
• An ICMPv6 Router Advertisement (RA) suggests to all IPv6 devices on the
link how it will receive IPv6 Address Information.
• Sent periodically by an IPv6 router or…
• … when the router receives a Router Solicitation message from a host.
©
Option 1 and 2: Stateless Address Autoconfiguration
Router Advertisement:
3 Options
• DHCPv6 Server does not maintain state of addresses
Option 3: Stateful Address Configuration
• Address received from DHCPv6 Server
Router(config)# ipv6 unicast-routing
DHCPv6
Option 1: SLAAC – No DHCPv6 (Default on Cisco routers)
DHCPv6 Server
“I’m everything you need (Prefix, Prefix-length, Default Gateway)”
Option 2: SLAAC + Stateless DHCPv6 for DNS address
“Here is my information but you need to get other information such
as DNS addresses from a DHCPv6 server.” (DNS can be in RA)
RA
Option 3: All addressing except default gateway use DHCPv6
“I can’t help you. Ask a DHCPv6 server for all your information.”
©
RA Message Options
ICMPv6 Router Advertisement
Option 1, 2, or 3
DHCPv6
Server
The type of Router Advertisement option depends on two RA flags:
Other Configuration Flag and Managed Configuration Flag
• Default: Both flags are set to 0 (Option 1)
• Use me (RA) for all your addressing information, no additional information
available via DHCPv6.
• Other Configuration Flag when set to “1” (Option 2)
• Use me (RA) for your address but you need to get OTHER information from
a stateless DHCPv6 server.
• Managed Configuration Flag when set to “1” (Option 3)
• The client needs to get ALL of it’s MANAGED information from a stateful
DHCPv6 server, except default gateway.
©
RA Message Options
ICMPv6 Router Advertisement
Option 1, 2, or 3
Option
Other Configuration
(“O”) Flag
DHCPv6
Server
Managed Configuration
(“M”) Flag
Option 1: SLAAC – No DHCPv6
(Default on Cisco routers)
0
0
Option 2: SLAAC + Stateless
DHCPv6 for DNS address
1
0
Option 3: All addressing except
default gateway use DHCPv6
0
1
©
Option 3 and the “A” Flag
G 0/1
As a Windows host I will still
use the RA prefix to create
temporary (SLAAC) addresses)
ICMPv6 RA
M Flag = 1
A Flag = 10
DHCPv6
DHCPv6 Server
Option
Managed
Configuration
(“M”) Flag
Option 3: All addressing
The autonomous
except
default gateway address
use
DHCPv6
they
can create an address
Address
Autoconfiguration
(“A”) Flag
Prefix in RA can
be used for
SLAAC
1
1 (default)
Yes
configuration (A) flag tells hosts that
for themselves by combining the prefix
Option
All addressing
in the3:RA
with an interface identifier.
1
0
No
except default gateway
use DHCPv6
©
Obtaining an IPv6 Address Automatically
©
8.2: Stateless DHCPv6
DHCPv6
Global Unicast
Manual
Dynamic
Stateless
Static
IPv6
unnumbered
Stateful
SLAAC
DHCPv6
SLAAC +
DHCPv6
DHCPv6-PD
Similar to IPv4 unnumbered
Static + EUI 64
•
SLAAC was discussed in Lesson 7.
©
RA Message
Option 1 and 2: Stateless Address Autoconfiguration
• DHCPv6 Server does not maintain state of addresses
Option 3: Stateful Address Configuration
• Address received from DHCPv6 Server
Router(config)# ipv6 unicast-routing
DHCPv6
Option 1: SLAAC – No DHCPv6 (Default on Cisco routers)
DHCPv6 Server
“I’m everything you need (Prefix, Prefix-length, Default Gateway)”
Option 2: SLAAC + Stateless DHCPv6 for DNS address
“Here is my information but you need to get other information such
as DNS addresses from a DHCPv6 server.” (DNS can be in RA)
RA
Option 3: All addressing except default gateway use DHCPv6
“I can’t help you. Ask a DHCPv6 server for all your information.”
©
Router as a Stateless DHCPv6 Server
ICMPv6 Router Solicitation
IPv6 Router &
DHCPv6 Server
2
•
Note: Domain name and DNS •
ICMPv6 Router Advertisement
Option 2: Stateless DHCPv6
O Flag = 1, M Flag = 0
server list may be included if
router (and end system) support
RFC 6106 IPv6 RA Options for
DNS Configuration.
4
6
1
DHCPv6
SOLICIT
To all DHCPv6 Servers
3
INFORMATION REQUEST
To all DHCPv6 Servers
5
ADVERTISE
Unicast
I created my own address
(Stateless),
and have the default
gateway, but I need a
DNS address…
REPLY
Unicast
©
Setting the Other Configuration Flag
G 0/0
ICMPv6 Router Advertisement
•
•
Option 2: Stateless DHCPv6
O Flag = 1, M Flag = 0
Router(config)# interface gigabitethernet 0/0
Router(config-if)# ipv6 nd other-config-flag
©
SLAAC for Addressing & DNS for Other Information
MAC: 00-19-D2-8C-E0-4C
2001:DB8:CAFE:1::/64
RA Message: Stateless DHCPv6
To:
1
2
FF02::1 (All-IPv6 devices)
From: FE80::1 (Link-local address)
Prefix: 2001:DB8:CAFE:1::
Prefix: 2001:DB8:CAFE:1::
RA
Prefix-length: /64
Prefix-length: /64
Default Gateway: FE80::1
Other Configuration Flag: 1
Global Unicast Address:
2001:DB8:CAFE:1:6909:cb1c:36a0:a595
2001:DB8:CAFE:1: + Interface ID
DHCPv6
For DNS
Stateless DHCPv6 Server
3
EUI-64 Process or
Random 64-bit value
©
Configuring Router as a Stateless DHCPv6 Server
IPv6 Router &
DHCPv6 Server
RA
0=1
DHCPv6
Step 1: Enable IPv6 routing to send ICMPv6 Router Advertisement
Router(config)# ipv6 unicast-routing
Step 2: Configure “stateless” DHCPv6 and parameters
Router(config)# ipv6 dhcp pool pool-name
Router(config-dhcpv6)# dns-server dns-server-address
Router(config-dhcpv6)# domain-name domain-name
No client
address
information.
Step 3: Configure interface: RA message and DHCPv6 server
Router(config)# interface type number
Router(config-if)# ipv6 nd other-config-flag
Router(config-if)# ipv6 dhcp server pool-name
©
Configuring Router as a Stateless DHCPv6 Server
IPv6 Router &
DHCPv6 Server
G0/0
:1
2001:DB8:CAFE:1/64
RA Message
O Flag = 1, M Flag = 0
DNS Server
2001:DB8:CAFE:9::99
DHCPv6
I created my own address
(Stateless),
and now I need to get a DNS
address using stateless DHCPv6.
©
Configuring Router as a Stateless DHCPv6 Server
DNS Server
2001:DB8:CAFE:9::99
G0/0
:1
2001:DB8:CAFE:1/64
RA
O=1
DHCPv6
Router(config)# ipv6 unicast-routing
Router(config)# ipv6 dhcp pool IPV6-STATELESS
Router(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99
Router(config-dhcpv6)# domain-name www.example.com
Router(config)# interface GigabitEthernet 0/0
Router(config-if)# ipv6 address 2001:DB8:CAFE:1::1/64
Router(config-if)# ipv6 address FE80::1 link-local
Router(config-if)# ipv6 nd other-config-flag
Router(config-if)# ipv6 dhcp server IPV6-STATELESS
©
Verifying Stateless DHCPv6 Server Configuration
DNS Server
2001:DB8:CAFE:9::99
G0/0
:1
2001:DB8:CAFE:1/64
RA
O=1
DHCPv6
PC> ipconfig /all
Physical Address. .
IPv6 Address. . . .
Default Gateway . .
DNS Servers . . . .
Connection-specific
. .: 00-21-9B-88-0E-40
Random 64 bits
. .: 2001:db8:cafe:1:6909:cb1c:36a0:a595
. .: fe80::1
. .: 2001:db8:cafe:9::99
DNS Suffix Search List: www.example.com
©
Verifying Stateless DHCPv6 Server Configuration
DNS Server
2001:DB8:CAFE:9::99
G0/0
:1
2001:DB8:CAFE:1/64
RA
O=1
DHCPv6
Router# show ipv6 interface gigabitethernet 0/0
GigabitEthernet 0/0 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::1
Global unicast address(es):
2001:DB8:CAFE:1::1, subnet is 2001:DB8:CAFE:1::/64
<Output omitted>
Hosts use stateless autoconfig for addresses.
Hosts use DHCP to obtain other configuration.
Router#
©
8.3: Stateful DHCPv6
RA Message
Option 1 and 2: Stateless Address Autoconfiguration
• DHCPv6 Server does not maintain state of addresses
Option 3: Stateful Address Configuration
• Address received from DHCPv6 Server
Router(config)# ipv6 unicast-routing
DHCPv6
Option 1: SLAAC – No DHCPv6 (Default on Cisco routers)
DHCPv6 Server
“I’m everything you need (Prefix, Prefix-length, Default Gateway)”
Option 2: SLAAC + Stateless DHCPv6 for DNS address
“Here is my information but you need to get other information such
as DNS addresses from a DHCPv6 server.” (DNS can be in RA)
RA
Option 3: All addressing except default gateway use DHCPv6
“I can’t help you. Ask a DHCPv6 server for all your information.”
©
Router as a Stateful DHCPv6 Server
ICMPv6 Router Solicitation
IPv6 Router &
DHCPv6 Server
2
1
ICMPv6 Router Advertisement
•
•
Option 3: Stateful DHCPv6
O Flag = 0, M Flag = 1
DHCPv6
4
6
SOLICIT
To all DHCPv6 Servers
3
REQUEST
To all DHCPv6 Servers
5
ADVERTISE
Unicast
I’m only using the default
gateway address from the
RA. I need to contact a
stateful DHCPv6 server
for all my addressing.
REPLY
Unicast
©
Setting the Managed Configuration Flag
G 0/1
ICMPv6 Router
Advertisement
•
•
DHCPv6
DHCPv
6
Server
Option 3 Stateful DHCPv6
O Flag = 0, M Flag = 1
Router(config)# interface gigabitethernet 0/1
Router(config-if)# ipv6 nd managed-config-flag
©
Stateful DHCPv6 without SLAAC
G 0/1
ICMPv6 Router
Advertisement
•
•
•
As a Windows host I will still
use the RA prefix to create
temporary (SLAAC) addresses)
DHCPv6
Option 3 Stateful DHCPv6
O Flag = 0, M Flag = 1
No SLAAC: A Flag = 0
DHCPv
6
Server
Router(config)# interface gigabitethernet 0/1
Router(config-if)# ipv6 nd managed-config-flag
Router(config-if)# ipv6 nd prefix prefix/length no-autoconfig
•
•
no-autoconfig (Optional) Indicates to hosts on the local link that the specified
prefix cannot be used for IPv6 autoconfiguration (SLAAC).
The prefix will be advertised with the A-bit clear (autonomous addressconfiguration flag).
©
As a Windows host I will still
use the RA prefix to create
temporary (SLAAC) addresses)
Stateful DHCPv6
2001:DB8:CAFE:2::/64
RA Message: Stateful DHCPv6
To:
1
2
FF02::1 (All-IPv6 devices)
From: FE80::1 (Link-local address)
Prefix: 2001:DB8:CAFE:2::
Default Gateway: FE80::1
RA
Global Unicast Address: DHCPv6
Prefix-length: /64
Managed Configuration Flag: 1
Autonomous Address Flag: 0
DHCPv6
Stateful DHCPv6 Server
©
Configuring Router as a Stateful DHCPv6 Server
IPv6 Router &
DHCPv6 Server
RA
M = 1 A=1
DHCPv6
Step 1: Enable IPv6 routing to send ICMPv6 Router Advertisement
Router(config)# ipv6 unicast-routing
Step 2: Configure “stateful” DHCPv6 and parameters
Router(config)# ipv6 dhcp pool pool-name
Router(config-dhcpv6)# address prefix prefix/length
Router(config-dhcpv6)# dns-server dns-server-address
Router(config-dhcpv6)# domain-name domain-name
Client address
information.
Step 3: Configure interface: RA message and DHCPv6 server
Router(config)# interface type number
Router(config-if)# ipv6 nd managed-config-flag
Router(config-if)# ipv6 nd prefix prefix/prefix-length no-autoconfig
©
Router(config-if)# ipv6 dhcp server pool-name
Configuring Router as a Stateful DHCPv6 Server
DNS Server
2001:DB8:CAFE:9::99
G0/1
:1
2001:DB8:CAFE:2/64
RA
M=1
DHCPv6
Router(config)# ipv6 unicast-routing
Router(config)# ipv6 dhcp pool IPV6-STATEFUL
Router(config-dhcpv6)# address prefix 2001:DB8:CAFE:2:DEED::/80
Router(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99
Router(config-dhcpv6)# domain-name www.example.com
Router(config)# interface GigabitEthernet 0/1
Router(config-if)# ipv6 address 2001:DB8:CAFE:2::1/64
Router(config-if)# ipv6 address FE80::1 link-local
Router(config-if)# ipv6 nd managed-config-flag
Router(config-if)# ipv6 dhcp server IPV6-STATEFUL
©
Including Only Valid Addresses to Be Assigned
• With IPv4, a router enabled as a DHCPv4 server we specifically
EXCLUDE addresses from being assigned.
• All other addresses are INCLUDED as possible assigned addresses.
Router-IPV4(config)# ip dhcp excluded-address 192.168.1.1 192.168.1.9
• With IPv6, a router enabled as a DHCPv6 server we specifically
INCLUDE addresses to be assigned.
• All other addresses are EXCLUDED as possible assigned addresses.
• Using the prefix length of the LAN may include the router’s address and
other statically assigned addresses.
Router(config-dhcpv6)# address prefix 2001:DB8:CAFE:2::/64
Router(config-dhcpv6)# address prefix 2001:DB8:CAFE:2:DEED::/80
©
Including Specific Addresses
Router(config-dhcpv6)# address prefix 2001:DB8:CAFE:2:DEED::/80
2001:DB8:CAFE:2::/64
2001:DB8:CAFE:2:0:0:0:0
2001:DB8:CAFE:2:FFFF:FFFF:FFFF:FFFF
/64
Available
addresses for this
network
/80
2001:DB8:CAFE:2:DEED::/80
2001:DB8:CAFE:2:DEED:0:0:0
2001:DB8:CAFE:2:DEED:0:0:1
2001:DB8:CAFE:2:DEED:0:0:2
INCLUDED assigned
addresses will have
these 80 bits.
. . .
All other addresses
are EXCLUDED
©
Verifying Stateful DHCPv6 Server Configuration
DNS Server
2001:DB8:CAFE:9::99
G0/1
:1
2001:DB8:CAFE:2/64
RA
M=1
DHCPv6
PC> ipconfig /all
Physical Address. .
IPv6 Address. . . .
Default Gateway . .
DNS Servers . . . .
Connection-specific
. .: 00-21-9B-88-0E-40
. .: 2001:db8:cafe:2:deed:2de8:cfd8:5
. .: fe80::1
. .: 2001:db8:cafe:9::99
DNS Suffix Search List: www.example.com
©
Verifying Stateful DHCPv6 Server Configuration
DNS Server
2001:DB8:CAFE:9::99
G0/1
:1
2001:DB8:CAFE:2/64
RA
M=1
DHCPv6
Router# show ipv6 interface gigabitethernet 0/1
GigabitEthernet 0/1 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::1
Global unicast address(es):
2001:DB8:CAFE:2::1, subnet is 2001:DB8:CAFE:2::/64
<output omitted>
Hosts use DHCP to obtain routable addresses.
Router#
©
Router(config)# ipv6 unicast-routing
Router(config)# ipv6 dhcp pool IPV6-STATELESS
Router(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99
Router(config-dhcpv6)# domain-name www.example.com
Stateless and Stateful
DHCPv6 Server
Router(config)# ipv6 dhcp pool IPV6-STATEFUL
Router(config-dhcpv6)# address prefix 2001:DB8:CAFE:2:DEED::/80
Router(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99
Router(config-dhcpv6)# domain-name www.example.com
Router(config)# interface GigabitEthernet 0/1
Router(config-if)# ipv6 address 2001:DB8:CAFE:2::1/64
Router(config-if)# ipv6 address FE80::1 link-local
Router(config-if)# ipv6 nd managed-config-flag
Router(config-if)# ipv6 dhcp server IPV6-STATEFUL
Stateless
G0/1
Stateful
Router(config)# interface GigabitEthernet 0/0
Router(config-if)# ipv6 address 2001:DB8:CAFE:1::1/64
Router(config-if)# ipv6 address FE80::1 link-local
Router(config-if)# ipv6 nd other-config-flag
Router(config-if)# ipv6 dhcp server IPV6-STATELESS
G0/0
©
8.4: DHCPv6 Relay
Forwarding DHCPv6 Messages
G0/0
:1
DHCPv6 Server
2001:DB8:CAFE:9::55
RELAY-FORWARD
G0/1
:1
2001:DB8:CAFE:2/64
DHCPv6
Router(config)# interface GigabitEthernet 0/1
Router(config-if)# ipv6 dhcp relay destination ipv6-address [exit-int]
Relay agent creates a RELAY-FORWARD message containing the original
DHCPv6 message from the client and forwards the message to a server.
The ipv6-address can be:
• Unicast or multicast IPv6 address
• Link-scope: The output interface must be specified for this kind of address.
©
Forwarding DHCPv6 Messages using unicast
G0/0
:1
DHCPv6 Server
2001:DB8:CAFE:9::55
G0/1
:1
2001:DB8:CAFE:2/64
RELAY-FORWARD
DHCPv6
To: 2001:DB8:CAFE:9::55
Router(config)# ipv6 unicast-routing
Only required if
link-local
unicast is used
Router(config)# interface GigabitEthernet 0/1
Router(config-if)# ipv6 nd managed-config-flag
Router(config-if)# ipv6 dhcp relay destination 2001:DB8:CAFE:9::55 g0/0
When the destination of the DHCP server is a global unicast address, no multicast
routing is required.
©
Forwarding DHCPv6 Messages using Multicast
G0/0
:1
DHCPv6 Server
2001:DB8:CAFE:9::55
G0/1
:1
2001:DB8:CAFE:2/64
RELAY-FORWARD
DHCPv6
To FF05::1:3 All-DHCPv6 Servers
Router(config)# ipv6 unicast-routing
Router(config)# ipv6 multicast-routing
Router(config)# interface GigabitEthernet 0/1
Router(config-if)# ipv6 nd managed-config-flag
Router(config-if)# ipv6 dhcp relay destination FF05::1:3
When the destination of the DHCP server is FF05::1:3 (All-DHCPv6 Servers)
multicast address, then we need multicast routing enabled for IPv6.
©
8.5: DHCPv6 Prefix Delegation Process
DHCPv4 and Private Addresses for the Home
NAT
ISP
DHCPv4
G0/1
Public IPv4 Address
for the interface
G0/1
HOME
DHCPv4
G0/0
Private IPv4 Address
10.0.0.0/8
172.16.0.0/12
192.168.0.0/16
• ISP only has to deliver a public IPv4 address for Home router interface.
• DHCPv4 and RFC 1918 private address space is used for home
network.
• NAT is used for translation – but has its drawbacks!
• No NAT between private-public IPv6 (always in debate)
©
The World of IPv6 and DHCPv6-PD
Complete IPv6 Reachability
Delegating
Router (DR)
ISP-DR
Requesting
Router (RR)
G0/1
G0/1 HOME-RR G0/0
Global IPv6 Address
Global IPv6 Address
• IPv6 end-to-end reachability:
• Home network gets its own IPv6 prefix (public address)
• No NAT
• Uses DHCPv6-PD (Prefix Delegation)
• ISP router is known as the Delegating Router (DR)
• HOME router is known as the Requesting Router (RR)
©
HOME Router’s ISP Facing Interface
Delegating
Router (DR)
ISP-DR
Requesting
Router (RR)
G0/1
IPv6 Address for the interface:
• SLAAC
• DHCPv6 (Stateful or Stateless)
G0/1 HOME-RR G0/0
?
• First, HOME’s ISP facing interface needs an IPv6 address.
• Similar to any IPv6 client it may dynamically get an address using:
• SLAAC - Using prefix in RA
• Stateless DHCPv6 – SLAAC but DHCPv6 for DNS address
• Stateful DHCPv6 - Like DHCPv4
• What about the address for the HOME LAN?
©
DHCPv6-PD Steps Overview
Delegating
Router (DR)
ISP-DR
Requesting
Router (RR)
G0/1
G0/1 HOME-RR G0/0
Global IPv6 Address
Global IPv6 Address
HOME-RR first gets an IPv6 address on its ISP-facing interface, then:
• Step 1: Request a Prefix for its LAN(s)
• Step 2: Subnet the prefix for its LANs (optional) – Get a /48 but assign /64s
• Step 3: Assign an IPv6 address from the prefix to its LAN interface
Advertises the prefix in a Router Advertisement to devices on the LAN
©
DHCPv6 Steps 1 and 2
Delegating
Router (DR)
ISP-DR
Requesting
Router (RR)
G0/1
G0/1 HOME-RR G0/0
DHCPv6-PD REQUEST
2
1
G0/2
DHCPv6-PD REPLY with /48 prefix
Step 1. HOME asks the ISP for an address to allocate for it’s LANs
• DHCPv6-PD is initiated by the RR
Step 2. ISP delegates an IPv6 prefix for HOME
• Example: ISP sends HOME a /48 prefix
©
DHCPv6 Step 3
Delegating
Router (DR)
ISP-DR
2
Requesting
Router (RR)
3
RA
RA
with
with
/64
prefix
prefix
G0/1 HOME-RR G0/0 3
G0/2
1
DHCPv6-PD REQUEST
G0/1
DHCPv6-PD REPLY with /48 prefix
Step 3. HOME advertises prefix using SLAAC RA messages (currently only option)
• HOME assigns an address from the prefix to its LAN interface and…
advertises the prefix out its interface using ICMPv6 RA messages
• HOME assigns the prefix or subnets of the prefix to one or more interfaces
• Example: HOME interfaces are assigned /64 subnets from the /48 prefix
©
8.6: DHCPv6-PD Configuration
Example
Our Example
2001:DB8:FEED:6::/64
G0/1
ISP-DR
SLAAC
2001:DB8:AB00:1::/64
G0/0
G0/1
EUI-64 HOME-RR :1
Router Advertisement
2001:DB8:FEED:6::/64
SLAAC
DHCPv6-PD
•
•
•
•
•
Prefix Delegation for the HOME
2001:DB8:AB00:/48
Router Advertisement
2001:DB8:AB00:1::/64
HOME’s G0/1 interface gets an address using SLAAC
ISP delegates 2001:DB8:AB00::/48 prefix to HOME for its LANs using DHCP-PD
HOME will use the 2001:DB8:AB00:1::/64 subnet for its G0/0 LAN.
Assign :1 to the G0/0 interface
HOME will send 2001:DB8:AB00:1::/64 prefix and other information in RA.
©
Another Look at the Process
ICMPv6 Router Solicitation
ICMPv6 Router Advertisement
G0/1
Other options are Stateless
and Stateful DHCPv6
G0/0
G0/1
EUI-64 HOME-RR :1
ISP-DR
SOLICIT: Prefix Delegation request
RR must be enabled with the PD option
ADVERTISE
DHCPv6-PD
REQUEST
REPLY: Include Prefix
SLAAC
ICMPv6 Router Advertisement (RA)
©
HOME-RR Configuration (1 of 2)
G0/1
ISP-DR
G0/0
G0/1
EUI-64 HOME-RR
Router Solicitation
Router Advertisement
DHCPv6-PD Request
HOME(config)# ipv6 unicast-routing
HOME(config)# interface gig 0/1
HOME(config-if)# ipv6 address autoconfig default
HOME(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP
! Required to send RA
! for LAN (next slide)
! Use RA & add default
! Request DHCPv6-PD
HOME(config)# interface gig 0/0
HOME(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
! Next slide
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HOME-RR Configuration (2 of 2)
G0/1
ISP-DR
2001:DB8:AB00:1::/64
G0/0
G0/1
EUI-64 HOME-RR ::1
DHCPv6-PD Request
Router Advertisement
DHCPv6-PD Reply
2001:DB8:AB00:1::/64
2001:DB8:AB00::/48
HOME(config)# ipv6 unicast-routing
! Required to send RA
! for LAN (next slide)
HOME(config)# interface gig 0/1
HOME(config-if)# ipv6 address autoconfig default
HOME(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP
! Use RA & add default
! Request DHCPv6-PD
Prefix Length
HOME(config)# interface gig 0/0
HOME(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64 ! For RA
First 48 bits uses prefix in DHCPv6-PD 2001:DB8:AB00::
Subnet-ID Interface ID
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ISP-DR Configuration (1 of 2)
ISP-DR
DNS
Server
2001:DB8:FEED:6::/64
G0/1
G0/0
G0/1
RA
EUI-64 HOME-RR
DHCPv6-PD Request
DHCPv6-PD Reply
2001:DB8:AB00::/48
2001:DB8:AB00::/48
ISP(config)# ipv6 unicast-routing
ISP(config)# interface gig 0/1
ISP(config-if)# ipv6 address 2001:db8:feed:6::1/64
ISP(config-if)# ipv6 address fe80::feed:1 link-local
ISP(config-if)# ipv6 dhcp server DHCPV6-CLIENT-ADDRESS
ISP(config)# ipv6 dhcp pool DHCPV6-CLIENT-ADDRESS
ISP(config-dhcpv6)# prefix-delegation pool DHCPV6-PD-POOL
ISP(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99
ISP(config-dhcpv6)# domain-name example.com
ISP(config)# ipv6 local pool DHCPV6-PD-POOL 2001:DB8:AB00::/40 48
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ISP-DR Configuration (2 of 2)
ISP-DR
2001:DB8:FEED:6::/64
G0/1
G0/0
G0/1
EUI-64 HOME-RR
2001:DB8:AB00::/40
2001:DB8:AB00::/48
2001:DB8:AB01::/48
2001:DB8:AB02::/48
…
2001:DB8:ABFF::/48
DHCPv6-PD Reply
2001:DB8:AB00::/48
ISP(config)# ipv6 dhcp pool DHCPV6-CLIENT-ADDRESS
ISP(config-dhcpv6)# prefix-delegation pool DHCPV6-PD-POOL
ISP(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99
ISP(config-dhcpv6)# domain-name example.com
From the /40 each DHCPv6PD client will get a /48
ISP(config)# ipv6 local pool DHCPV6-PD-POOL 2001:DB8:AB00::/40 48
Reserve a /40 to allocate addresses for ISP’s
DHCPv6-PD clients 2001:DB8:ABxx::/40
! PD pool
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HOME-RR Applies DHCPv6-PD Information on G0/0
ISP-DR
2001:DB8:FEED:6::/64
2001:DB8:AB00:1::/64
G0/1
G0/0
G0/1
EUI-64 HOME-RR ::1
DHCPv6-PD Reply
2001:DB8:AB00::/48
Router Advertisement
2001:DB8:AB00:1::/64
Prefix
ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
First 48 bits uses prefix in DHCPv6-PD 2001:DB8:AB00:: Subnet-ID
Interface ID
ISP(config)# ipv6 dhcp pool DHCPV6-CLIENT-ADDRESS
ISP(config-dhcpv6)# prefix-delegation pool DHCPV6-PD-POOL
ISP(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99
ISP(config)# ipv6 local pool DHCPV6-PD-POOL 2001:DB8:AB00::/40 48
! PD pool
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8.7: Verifying DHCPv6-PD
Verifying ISP-DR DHCPv6 Pool
ISP-DR
2001:DB8:FEED:6::/64
2001:DB8:AB00:1::/64
G0/1
G0/0
G0/1
EUI-64 HOME-RR ::1
ISP# show ipv6 dhcp interface gig 0/1
GigabitEthernet0/1 is in server mode
Using pool: DHCPV6-CLIENT-ADDRESS
Preference value: 0
Hint from client: ignored
Rapid-Commit: disabled
ISP#
ISP(config)# interface gig 0/1
ISP(config-if)# ipv6 dhcp server DHCPV6-CLIENT-ADDRESS
ISP(config)# ipv6 dhcp pool DHCPV6-CLIENT-ADDRESS
ISP(config-dhcpv6)# prefix-delegation pool DHCPV6-PD-POOL
ISP(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99
ISP(config)# ipv6 local pool DHCPV6-PD-POOL 2001:DB8:AB00::/40 48
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Verifying ISP-DR DHCPv6 Pool Information
ISP-DR
2001:DB8:FEED:6::/64
2001:DB8:AB00:1::/64
G0/1
G0/0
G0/1
EUI-64 HOME-RR ::1
ISP# show ipv6 local pool DHCPV6-PD-POOL
Prefix is 2001:DB8:AB00::/40 assign /48 prefix
1 entries in use, 255 available, 0 rejected
0 entries cached, 1000 maximum
User
Prefix
Interface
00030001885A923B29E000040001
2001:DB8:AB00::/48
ISP#
Reserve a /40 to allocate
addresses for ISP’s DHCPv6PD clients 2001:DB8:ABxx::/40
From the /40 each DHCPv6PD client will get a /48
ISP(config)# ipv6 local pool DHCPV6-PD-POOL 2001:DB8:AB00::/40 48
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Verifying HOME-RR Addresses
ISP-DR
2001:DB8:FEED:6::/64
2001:DB8:AB00:1::/64
G0/1
G0/0
G0/1
EUI-64 HOME-RR ::1
HOME# show ipv6 interface brief
GigabitEthernet0/0
[up/up]
FE80::1
DHCPv6-PD
2001:DB8:AB00:1::1
GigabitEthernet0/1
[up/up]
FE80::8A5A:92FF:FE3B:29E1
SLAAC
2001:DB8:FEED:6:8A5A:92FF:FE3B:29E1
HOME-RR#
HOME(config)# ipv6 unicast-routing
HOME(config)# interface gig 0/1
HOME(config-if)# ipv6 address autoconfig default
HOME(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP
HOME(config)# interface gig 0/0
HOME(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
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Verifying HOME-RR Addresses
ISP-DR
2001:DB8:FEED:6::/64
2001:DB8:AB00:1::/64
G0/1
G0/0
G0/1
EUI-64 HOME-RR ::1
Router Advertisement
HOME# show ipv6 interface gig 0/0
2001:DB8:AB00:1::/64
GigabitEthernet0/0 is up, line protocol is up
General-prefix in use for addressing
Global unicast address(es):
2001:DB8:AB00:1::1, subnet is 2001:DB8:AB00:1::/64 [CAL/PRE]
<Output ommited>
Hosts use stateless autoconfig for addresses.
HOME#
HOME(config)# ipv6 unicast-routing
HOME(config)# interface gig 0/1
HOME(config-if)# ipv6 address autoconfig default
HOME(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP
HOME(config)# interface gig 0/0
HOME(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
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Verifying HOME-RR Routing Table
2001:DB8:FEED:6::/64
2001:DB8:AB00:1::/64
G0/1
G0/0
G0/1
EUI-64 HOME-RR ::1
ISP-DR
Default Route
HOME# show ipv6 route
X 2001:DB8:AB00::/48
IPv6 Routing Table - default - 7 entries
Codes: ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr – Redirect
ND
::/0 [2/0]
via FE80::FEED:1, GigabitEthernet0/1
S
2001:DB8:AB00::/48 [1/0]
via Null0, directly connected
<Output omitted>
HOME(config)# ipv6 unicast-routing
HOME#
HOME(config)# interface gig 0/1
HOME(config-if)# ipv6 address autoconfig default
HOME(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP
HOME(config)# interface gig 0/0
HOME(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
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For more information please check out my Cisco Press book and video series:
IPv6 Fundamentals: A Straightforward
Approach to Understanding IPv6
•
By Rick Graziani
•
ISBN-10: 1-58714-313-5
IPv6 Fundamentals LiveLessons: A
Straightforward Approach to Understanding IPv6
•
By Rick Graziani
•
ISBN-10: 1-58720-457-6
©
8: DHCPv6 (Dynamic Host
Configuration Protocol for IPv6)
Rick Graziani
Cabrillo College
Rick.Graziani@cabrillo.edu