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8: DHCPv6 (Dynamic Host Configuration Protocol for IPv6)
Rick GrazianiCabrillo College
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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
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DHCPv6
Global Unicast
Manual Dynamic
StaticIPv6
unnumbered
Static + EUI 64
SLAAC DHCPv6
SLAAC + DHCPv6
Similar to IPv4 unnumbered
Stateless Stateful
DHCPv6-PD
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DHCP Server
Dynamic IPv4 Address Allocation
DHCP Client
I need an IPv4 addressing information from a DHCP server.
Here is your IPv4 address, subnet mask,
default gateway and DNS server addresses.
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All Dynamic Addressing Begins with the RA Message
• 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.
DHCPv6 Server
ICMPv6 Router Advertisement
ICMPv6 Router Solicitation
Multicast: To all IPv6 routers, I need
IPv6 address information
Multicast: To all IPv6 devices,
let me tell you how to do this …
I might not even be needed.
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Router Advertisement: 3 Options
DHCPv6 Server
RA
Router(config)# ipv6 unicast-routing
Option 1: SLAAC – No DHCPv6 (Default on Cisco routers)
“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)
Option 3: All addressing except default gateway use DHCPv6
“I can’t help you. Ask a DHCPv6 server for all your information.”
DHCPv6
Option 1 and 2: Stateless Address Autoconfiguration• DHCPv6 Server does not maintain state of addressesOption 3: Stateful Address Configuration• Address received from DHCPv6 Server
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RA Message Options
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.
DHCPv6 Server
ICMPv6 Router AdvertisementOption 1, 2, or 3
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RA Message Options
DHCPv6 Server
ICMPv6 Router AdvertisementOption 1, 2, or 3
Option Other Configuration (“O”) Flag
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
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Option 3 and the “A” Flag
Option Managed Configuration (“M”) Flag
Address Autoconfiguration (“A”) Flag
Prefix in RA can be used for SLAAC
Option 3: All addressing except default gateway use DHCPv6
1 1 (default) Yes
Option 3: All addressing except default gateway use DHCPv6
1 0 No
ICMPv6 RAM Flag = 1A Flag = 1
G 0/1
DHCPv6
DHCPv6 Server
As a Windows host I will still use the RA prefix to create
temporary (SLAAC) addresses)
0
The autonomous address configuration (A) flag tells hosts that they can create an address for themselves by combining the prefix in the RA with an interface identifier.
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DHCPv6
• SLAAC was discussed in Lesson 7.
Global Unicast
Manual Dynamic
StaticIPv6
unnumbered
Static + EUI 64
SLAAC DHCPv6
SLAAC + DHCPv6
Similar to IPv4 unnumbered
Stateless Stateful
DHCPv6-PD
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RA Message
DHCPv6 Server
RA
Router(config)# ipv6 unicast-routing
Option 1: SLAAC – No DHCPv6 (Default on Cisco routers)
“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)
Option 3: All addressing except default gateway use DHCPv6
“I can’t help you. Ask a DHCPv6 server for all your information.”
DHCPv6
Option 1 and 2: Stateless Address Autoconfiguration• DHCPv6 Server does not maintain state of addressesOption 3: Stateful Address Configuration• Address received from DHCPv6 Server
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DHCPv6 I created my own address (Stateless),
and have the default gateway, but I need a
DNS address…
IPv6 Router & DHCPv6 Server
SOLICIT To all DHCPv6 Servers 3
ADVERTISE Unicast
INFORMATION REQUESTTo all DHCPv6 Servers
REPLY Unicast
Router as a Stateless DHCPv6 Server
ICMPv6 Router Advertisement
4
5
6
• Option 2: Stateless DHCPv6• O Flag = 1, M Flag = 0
ICMPv6 Router Solicitation 1
2
Note: Domain name and DNS server list may be included if router (and end system) support RFC 6106 IPv6 RA Options for DNS Configuration.
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Setting the Other Configuration Flag
ICMPv6 Router Advertisement
• Option 2: Stateless DHCPv6• O Flag = 1, M Flag = 0
Router(config)# interface gigabitethernet 0/0Router(config-if)# ipv6 nd other-config-flag
G 0/0
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RA Message: Stateless DHCPv6
To: FF02::1 (All-IPv6 devices)
From: FE80::1 (Link-local address)
Prefix: 2001:DB8:CAFE:1::
Prefix-length: /64
Other Configuration Flag: 1
RA
1
MAC: 00-19-D2-8C-E0-4C
Prefix: 2001:DB8:CAFE:1::
Prefix-length: /64
Default Gateway: FE80::1
Global Unicast Address:
2001:DB8:CAFE:1: + Interface ID
2001:DB8:CAFE:1::/64
EUI-64 Process or Random 64-bit value
2
Stateless DHCPv6 Server3
SLAAC for Addressing & DNS for Other Information
2001:DB8:CAFE:1:6909:cb1c:36a0:a595DHCPv6For DNS
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Configuring Router as a Stateless DHCPv6 Server
Step 1: Enable IPv6 routing to send ICMPv6 Router AdvertisementRouter(config)# ipv6 unicast-routing
Step 2: Configure “stateless” DHCPv6 and parametersRouter(config)# ipv6 dhcp pool pool-nameRouter(config-dhcpv6)# dns-server dns-server-addressRouter(config-dhcpv6)# domain-name domain-name
Step 3: Configure interface: RA message and DHCPv6 serverRouter(config)# interface type numberRouter(config-if)# ipv6 nd other-config-flagRouter(config-if)# ipv6 dhcp server pool-name
IPv6 Router & DHCPv6 Server
RA 0 = 1 DHCPv6
No client address information.
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IPv6 Router & DHCPv6 Server
2001:DB8:CAFE:1/64G0/0:1
DNS Server
Configuring Router as a Stateless DHCPv6 Server
RA Message
DHCPv6
O Flag = 1, M Flag = 0
I created my own address (Stateless),
and now I need to get a DNS address using stateless DHCPv6.
2001:DB8:CAFE:9::99
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Router(config)# ipv6 unicast-routing
Router(config)# ipv6 dhcp pool IPV6-STATELESSRouter(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99Router(config-dhcpv6)# domain-name www.example.com
Router(config)# interface GigabitEthernet 0/0Router(config-if)# ipv6 address 2001:DB8:CAFE:1::1/64Router(config-if)# ipv6 address FE80::1 link-localRouter(config-if)# ipv6 nd other-config-flagRouter(config-if)# ipv6 dhcp server IPV6-STATELESS
Configuring Router as a Stateless DHCPv6 Server2001:DB8:CAFE:1/64G0/0
:1DNS Server
2001:DB8:CAFE:9::99 RAO = 1
DHCPv6
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PC> ipconfig /all
Physical Address. . . .: 00-21-9B-88-0E-40 IPv6 Address. . . . . .: 2001:db8:cafe:1:6909:cb1c:36a0:a595 Default Gateway . . . .: fe80::1 DNS Servers . . . . . .: 2001:db8:cafe:9::99 Connection-specific DNS Suffix Search List: www.example.com
2001:DB8:CAFE:1/64G0/0:1
DNS Server
2001:DB8:CAFE:9::99 RAO = 1
DHCPv6
Verifying Stateless DHCPv6 Server Configuration
Random 64 bits
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Router# show ipv6 interface gigabitethernet 0/0GigabitEthernet 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#
2001:DB8:CAFE:1/64G0/0:1
DNS Server
2001:DB8:CAFE:9::99 RAO = 1
DHCPv6
Verifying Stateless DHCPv6 Server Configuration
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RA Message
DHCPv6 Server
RA
Router(config)# ipv6 unicast-routing
Option 1: SLAAC – No DHCPv6 (Default on Cisco routers)
“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)
Option 3: All addressing except default gateway use DHCPv6
“I can’t help you. Ask a DHCPv6 server for all your information.”
DHCPv6
Option 1 and 2: Stateless Address Autoconfiguration• DHCPv6 Server does not maintain state of addressesOption 3: Stateful Address Configuration• Address received from DHCPv6 Server
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DHCPv6 I’m only using the default gateway address from the
RA. I need to contact a stateful DHCPv6 server for all my addressing.
IPv6 Router & DHCPv6 Server
SOLICIT To all DHCPv6 Servers 3
ADVERTISE Unicast
REQUESTTo all DHCPv6 Servers
REPLY Unicast
Router as a Stateful DHCPv6 Server
ICMPv6 Router Advertisement
4
5
6
• Option 3: Stateful DHCPv6• O Flag = 0, M Flag = 1
ICMPv6 Router Solicitation 1
2
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Setting the Managed Configuration Flag
ICMPv6 Router Advertisement
• Option 3 Stateful DHCPv6 • O Flag = 0, M Flag = 1
Router(config)# interface gigabitethernet 0/1Router(config-if)# ipv6 nd managed-config-flag
G 0/1
DHCPv6
DHCPv6 Server
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Stateful DHCPv6 without SLAAC
ICMPv6 Router Advertisement
• Option 3 Stateful DHCPv6 • O Flag = 0, M Flag = 1• No SLAAC: A Flag = 0
Router(config)# interface gigabitethernet 0/1Router(config-if)# ipv6 nd managed-config-flagRouter(config-if)# ipv6 nd prefix prefix/length no-autoconfig
G 0/1
DHCPv6
DHCPv6 Server
• 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 address-configuration flag).
As a Windows host I will still use the RA prefix to create
temporary (SLAAC) addresses)
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RA Message: Stateful DHCPv6
To: FF02::1 (All-IPv6 devices)
From: FE80::1 (Link-local address)
Prefix: 2001:DB8:CAFE:2::
Prefix-length: /64
Managed Configuration Flag: 1
Autonomous Address Flag: 0
RA
1
Default Gateway: FE80::1
Global Unicast Address: DHCPv6
2001:DB8:CAFE:2::/64
2
Stateful DHCPv6 Server
Stateful DHCPv6
DHCPv6
As a Windows host I will still use the RA prefix to create
temporary (SLAAC) addresses)
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Configuring Router as a Stateful DHCPv6 Server
Step 1: Enable IPv6 routing to send ICMPv6 Router AdvertisementRouter(config)# ipv6 unicast-routing
Step 2: Configure “stateful” DHCPv6 and parametersRouter(config)# ipv6 dhcp pool pool-nameRouter(config-dhcpv6)# address prefix prefix/lengthRouter(config-dhcpv6)# dns-server dns-server-addressRouter(config-dhcpv6)# domain-name domain-name
Step 3: Configure interface: RA message and DHCPv6 serverRouter(config)# interface type numberRouter(config-if)# ipv6 nd managed-config-flagRouter(config-if)# ipv6 nd prefix prefix/prefix-length no-autoconfigRouter(config-if)# ipv6 dhcp server pool-name
IPv6 Router & DHCPv6 Server
RAM = 1 A=1 DHCPv6
Client address information.
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Router(config)# ipv6 unicast-routing
Router(config)# ipv6 dhcp pool IPV6-STATEFULRouter(config-dhcpv6)# address prefix 2001:DB8:CAFE:2:DEED::/80Router(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99Router(config-dhcpv6)# domain-name www.example.com
Router(config)# interface GigabitEthernet 0/1Router(config-if)# ipv6 address 2001:DB8:CAFE:2::1/64Router(config-if)# ipv6 address FE80::1 link-localRouter(config-if)# ipv6 nd managed-config-flagRouter(config-if)# ipv6 dhcp server IPV6-STATEFUL
Configuring Router as a Stateful DHCPv6 Server2001:DB8:CAFE:2/64G0/1
:1DNS Server
2001:DB8:CAFE:9::99 RAM = 1
DHCPv6
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Router-IPV4(config)# ip dhcp excluded-address 192.168.1.1 192.168.1.9
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.
• 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
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Including Specific Addresses
2001:DB8:CAFE:2::/642001:DB8:CAFE:2:0:0:0:02001:DB8:CAFE:2:FFFF:FFFF:FFFF:FFFF
2001:DB8:CAFE:2:DEED::/802001:DB8:CAFE:2:DEED:0:0:02001:DB8:CAFE:2:DEED:0:0:12001:DB8:CAFE:2:DEED:0:0:2 . . .
/64 /80
INCLUDED assigned addresses will have these 80 bits.
Available addresses for this network
Router(config-dhcpv6)# address prefix 2001:DB8:CAFE:2:DEED::/80
All other addresses are EXCLUDED
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PC> ipconfig /all
Physical Address. . . .: 00-21-9B-88-0E-40 IPv6 Address. . . . . .: 2001:db8:cafe:2:deed:2de8:cfd8:5 Default Gateway . . . .: fe80::1 DNS Servers . . . . . .: 2001:db8:cafe:9::99 Connection-specific DNS Suffix Search List: www.example.com
2001:DB8:CAFE:2/64G0/1:1
DNS Server
2001:DB8:CAFE:9::99 RAM = 1
DHCPv6
Verifying Stateful DHCPv6 Server Configuration
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Router# show ipv6 interface gigabitethernet 0/1GigabitEthernet 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#
2001:DB8:CAFE:2/64G0/1:1
DNS Server
2001:DB8:CAFE:9::99 RAM = 1
DHCPv6
Verifying Stateful DHCPv6 Server Configuration
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Router(config)# ipv6 unicast-routing
Router(config)# ipv6 dhcp pool IPV6-STATELESSRouter(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99Router(config-dhcpv6)# domain-name www.example.com
Router(config)# ipv6 dhcp pool IPV6-STATEFULRouter(config-dhcpv6)# address prefix 2001:DB8:CAFE:2:DEED::/80Router(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99Router(config-dhcpv6)# domain-name www.example.com
Router(config)# interface GigabitEthernet 0/0Router(config-if)# ipv6 address 2001:DB8:CAFE:1::1/64Router(config-if)# ipv6 address FE80::1 link-localRouter(config-if)# ipv6 nd other-config-flagRouter(config-if)# ipv6 dhcp server IPV6-STATELESS
Router(config)# interface GigabitEthernet 0/1Router(config-if)# ipv6 address 2001:DB8:CAFE:2::1/64Router(config-if)# ipv6 address FE80::1 link-localRouter(config-if)# ipv6 nd managed-config-flagRouter(config-if)# ipv6 dhcp server IPV6-STATEFUL
Stateless and Stateful DHCPv6 Server
G0/1
G0/0
StatelessS
tateful
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Forwarding DHCPv6 Messages
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.
2001:DB8:CAFE:2/64G0/1:1
DHCPv6 Server
2001:DB8:CAFE:9::55
DHCPv6
Router(config)# interface GigabitEthernet 0/1Router(config-if)# ipv6 dhcp relay destination ipv6-address [exit-int]
RELAY-FORWARD
G0/0:1
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Forwarding DHCPv6 Messages using unicast
When the destination of the DHCP server is a global unicast address, no multicast routing is required.
2001:DB8:CAFE:2/64G0/1:1
DHCPv6 Server
2001:DB8:CAFE:9::55
DHCPv6
Router(config)# ipv6 unicast-routing
Router(config)# interface GigabitEthernet 0/1Router(config-if)# ipv6 nd managed-config-flagRouter(config-if)# ipv6 dhcp relay destination 2001:DB8:CAFE:9::55 g0/0
RELAY-FORWARD
To: 2001:DB8:CAFE:9::55
G0/0:1
Only required if link-local unicast is used
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Forwarding DHCPv6 Messages using Multicast
When the destination of the DHCP server is FF05::1:3 (All-DHCPv6 Servers) multicast address, then we need multicast routing enabled for IPv6.
2001:DB8:CAFE:2/64G0/1:1
DHCPv6 Server
2001:DB8:CAFE:9::55
DHCPv6
Router(config)# ipv6 unicast-routingRouter(config)# ipv6 multicast-routing
Router(config)# interface GigabitEthernet 0/1Router(config-if)# ipv6 nd managed-config-flagRouter(config-if)# ipv6 dhcp relay destination FF05::1:3
RELAY-FORWARD
To FF05::1:3 All-DHCPv6 Servers
G0/0:1
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DHCPv4 and Private Addresses for the Home
• 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)
ISP HOME
Public IPv4 Addressfor the interface
G0/1 G0/1
10.0.0.0/8172.16.0.0/12192.168.0.0/16
G0/0
Private IPv4 Address
NAT
DHCPv4 DHCPv4
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The World of IPv6 and DHCPv6-PD
• 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)
ISP-DR HOME-RRG0/1 G0/1 G0/0
Delegating Router (DR)
Requesting Router (RR)
Global IPv6 Address Global IPv6 Address
Complete IPv6 Reachability
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HOME Router’s ISP Facing Interface
• 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?
ISP-DR HOME-RRG0/1 G0/1 G0/0
Delegating Router (DR)
Requesting Router (RR)
IPv6 Address for the interface:• SLAAC • DHCPv6 (Stateful or Stateless)
?
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DHCPv6-PD Steps Overview
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
ISP-DR HOME-RRG0/1 G0/1 G0/0
Delegating Router (DR)
Requesting Router (RR)
Global IPv6 Address Global IPv6 Address
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DHCPv6 Steps 1 and 2
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
ISP-DR HOME-RRG0/1 G0/1 G0/0
Delegating Router (DR)
Requesting Router (RR)
G0/2DHCPv6-PD REQUEST
DHCPv6-PD REPLY with /48 prefix
1
2
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DHCPv6 Step 3
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
ISP-DR HOME-RRG0/1 G0/1 G0/0
Delegating Router (DR)
Requesting Router (RR)
G0/2DHCPv6-PD REQUEST
DHCPv6-PD REPLY with /48 prefix
1
2
RA with /64 prefix3
RA with /64 prefix
3
RA with prefix
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Our Example
• 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.
ISP-DR HOME-RR
G0/1 G0/1EUI-64
G0/0:1
2001:DB8:AB00:1::/642001:DB8:FEED:6::/64
Router Advertisement2001:DB8:AB00:1::/64
Router Advertisement2001:DB8:FEED:6::/64
DHCPv6-PD Prefix Delegation for the HOME2001:DB8:AB00:/48
SLAAC
SLAAC
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Another Look at the Process
ISP-DR HOME-RR
G0/1 G0/1EUI-64
G0/0:1
ICMPv6 Router Advertisement
ICMPv6 Router Solicitation
SOLICIT: Prefix Delegation request
ADVERTISE
REQUEST
REPLY: Include Prefix
ICMPv6 Router Advertisement (RA)SLAAC
DHCPv6-PD
Other options are Stateless and Stateful DHCPv6
RR must be enabled with the PD option
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HOME-RR Configuration (1 of 2)
ISP-DR HOME-RR
G0/1 G0/1EUI-64
G0/0
Router Advertisement
Router Solicitation
DHCPv6-PD Request
HOME(config)# ipv6 unicast-routing ! Required to send RA ! for LAN (next slide)HOME(config)# interface gig 0/1HOME(config-if)# ipv6 address autoconfig default ! Use RA & add defaultHOME(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP ! Request DHCPv6-PD HOME(config)# interface gig 0/0HOME(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)
ISP-DR HOME-RR
G0/1 G0/1EUI-64
G0/0
HOME(config)# ipv6 unicast-routing ! Required to send RA ! for LAN (next slide)HOME(config)# interface gig 0/1HOME(config-if)# ipv6 address autoconfig default ! Use RA & add defaultHOME(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP ! Request DHCPv6-PD
HOME(config)# interface gig 0/0HOME(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64 ! For RA
Router AdvertisementDHCPv6-PD Request
DHCPv6-PD Reply
2001:DB8:AB00:1::/64
2001:DB8:AB00::/482001:DB8:AB00:1::/64
::1
First 48 bits uses prefix in DHCPv6-PD 2001:DB8:AB00::Subnet-ID Interface ID
Prefix Length
©
ISP-DR Configuration (1 of 2)
ISP-DR HOME-RR
G0/1 G0/1EUI-64
G0/0RA
DHCPv6-PD Reply2001:DB8:AB00::/48
ISP(config)# ipv6 unicast-routingISP(config)# interface gig 0/1ISP(config-if)# ipv6 address 2001:db8:feed:6::1/64ISP(config-if)# ipv6 address fe80::feed:1 link-localISP(config-if)# ipv6 dhcp server DHCPV6-CLIENT-ADDRESS
ISP(config)# ipv6 dhcp pool DHCPV6-CLIENT-ADDRESSISP(config-dhcpv6)# prefix-delegation pool DHCPV6-PD-POOLISP(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99ISP(config-dhcpv6)# domain-name example.com
ISP(config)# ipv6 local pool DHCPV6-PD-POOL 2001:DB8:AB00::/40 48
DHCPv6-PD Request
2001:DB8:FEED:6::/64
2001:DB8:AB00::/48
DNSServer
©
ISP-DR Configuration (2 of 2)
ISP-DR HOME-RR
G0/1 G0/1EUI-64
G0/0
DHCPv6-PD Reply2001:DB8:AB00::/48
2001:DB8:FEED:6::/64
2001:DB8:AB00::/40
2001:DB8:AB00::/482001:DB8:AB01::/48 2001:DB8:AB02::/48 …2001:DB8:ABFF::/48
ISP(config)# ipv6 dhcp pool DHCPV6-CLIENT-ADDRESSISP(config-dhcpv6)# prefix-delegation pool DHCPV6-PD-POOLISP(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99ISP(config-dhcpv6)# domain-name example.com
ISP(config)# ipv6 local pool DHCPV6-PD-POOL 2001:DB8:AB00::/40 48 ! PD pool
Reserve a /40 to allocate addresses for ISP’s DHCPv6-PD clients 2001:DB8:ABxx::/40
From the /40 each DHCPv6-PD client will get a /48
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HOME-RR Applies DHCPv6-PD Information on G0/0
ISP-DR HOME-RR
G0/1 G0/1EUI-64
G0/0
DHCPv6-PD Reply2001:DB8:AB00::/48
2001:DB8:FEED:6::/64
ISP(config)# ipv6 dhcp pool DHCPV6-CLIENT-ADDRESSISP(config-dhcpv6)# prefix-delegation pool DHCPV6-PD-POOLISP(config-dhcpv6)# dns-server 2001:DB8:CAFE:9::99
ISP(config)# ipv6 local pool DHCPV6-PD-POOL 2001:DB8:AB00::/40 48 ! PD pool
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
Prefix
::1
2001:DB8:AB00:1::/64
Router Advertisement2001:DB8:AB00:1::/64
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Verifying ISP-DR DHCPv6 Pool
ISP-DR HOME-RR
G0/1 G0/1EUI-64
G0/02001:DB8:FEED:6::/64
::1
2001:DB8:AB00:1::/64
ISP# show ipv6 dhcp interface gig 0/1GigabitEthernet0/1 is in server mode Using pool: DHCPV6-CLIENT-ADDRESS Preference value: 0 Hint from client: ignored Rapid-Commit: disabledISP# ISP(config)# interface gig 0/1
ISP(config-if)# ipv6 dhcp server DHCPV6-CLIENT-ADDRESS
ISP(config)# ipv6 dhcp pool DHCPV6-CLIENT-ADDRESSISP(config-dhcpv6)# prefix-delegation pool DHCPV6-PD-POOLISP(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 HOME-RR
G0/1 G0/1EUI-64
G0/02001:DB8:FEED:6::/64
::1
2001:DB8:AB00:1::/64
ISP# show ipv6 local pool DHCPV6-PD-POOLPrefix is 2001:DB8:AB00::/40 assign /48 prefix1 entries in use, 255 available, 0 rejected0 entries cached, 1000 maximumUser Prefix Interface 00030001885A923B29E000040001 2001:DB8:AB00::/48 ISP#
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
From the /40 each DHCPv6-PD client will get a /48
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Verifying HOME-RR Addresses
ISP-DR HOME-RR
G0/1 G0/1EUI-64
G0/02001:DB8:FEED:6::/64
::1
2001:DB8:AB00:1::/64
HOME# show ipv6 interface briefGigabitEthernet0/0 [up/up] FE80::1 2001:DB8:AB00:1::1GigabitEthernet0/1 [up/up] FE80::8A5A:92FF:FE3B:29E1 2001:DB8:FEED:6:8A5A:92FF:FE3B:29E1HOME-RR#
HOME(config)# ipv6 unicast-routingHOME(config)# interface gig 0/1HOME(config-if)# ipv6 address autoconfig default HOME(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP
HOME(config)# interface gig 0/0HOME(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
DHCPv6-PD
SLAAC
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Verifying HOME-RR Addresses
ISP-DR HOME-RR
G0/1 G0/1EUI-64
G0/02001:DB8:FEED:6::/64
::1
2001:DB8:AB00:1::/64
HOME# show ipv6 interface gig 0/0GigabitEthernet0/0 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-routingHOME(config)# interface gig 0/1HOME(config-if)# ipv6 address autoconfig default HOME(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP
HOME(config)# interface gig 0/0HOME(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
Router Advertisement2001:DB8:AB00:1::/64
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Verifying HOME-RR Routing Table
ISP-DR HOME-RR
G0/1 G0/1EUI-64
G0/02001:DB8:FEED:6::/64
::1
2001:DB8:AB00:1::/64
HOME# show ipv6 routeIPv6 Routing Table - default - 7 entriesCodes: ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr – Redirect
ND ::/0 [2/0] via FE80::FEED:1, GigabitEthernet0/1S 2001:DB8:AB00::/48 [1/0] via Null0, directly connected<Output omitted>HOME# HOME(config)# ipv6 unicast-routing
HOME(config)# interface gig 0/1HOME(config-if)# ipv6 address autoconfig default HOME(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP
HOME(config)# interface gig 0/0HOME(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
Default Route2001:DB8:AB00::/48X
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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 GrazianiCabrillo College