Stateless DHCPv6 + SLAAC [2/4]

This is a common LAN Deployment model in which DHCPv6 is used to advertise DNS and domain name and IPv6 prefixes are assigned using classic SLAAC (Stateless Address Auto-Configuration).

(Server configuration [> 12.4(24) T])

ipv6 dhcp pool SLAAC-POOL

dns-server XXXX:YYYY:8B6B:90E0::57

dns-server 2001:DB8::57



interface FastEthernet0/1

ipv6 address 2001:DB8:23::2/64

ipv6 nd other-config-flag

ipv6 dhcp server SLAAC-POOL rapid-commit


The Client gets the prefix from ND protocol (Network Discovery) through RS (Router Solicitation)/RA (Router Advertisement).

The Server sets a special flag in RA message to inform the client that it can get other stateful information like DNS and domain name through DHCP request.

Picture1: Stateless message exchange

Picture2: RA special flag

Client configuration [> 12.4(24) T]:

interface FastEthernet0/0

ipv6 address autoconfig

ipv6 enable





*Oct 24 00:51:45.989: IPv6 DHCP: Sending INFORMATION-REQUEST to FF02::1:2 on FastEthernet0/0

*Oct 24 00:51:45.989: IPv6 DHCP: DHCPv6 changes state from IDLE to INFORMATION-REQUEST (STATELESS) on FastEthernet0/0

*Oct 24 00:51:46.001: IPv6 DHCP: Received REPLY from FE80::C803:37FF:FEAC:6 on FastEthernet0/0

*Oct 24 00:51:46.001: IPv6 DHCP: Adding server FE80::C803:37FF:FEAC:6

*Oct 24 00:51:46.005: IPv6 DHCP: Processing options

*Oct 24 00:51:46.005: IPv6 DHCP: Configuring DNS server XXXX:YYYY:8B6B:90E0::57

*Oct 24 00:51:46.005: IPv6 DHCP: Configuring DNS server 2001:DB8::57

*Oct 24 00:51:46.005: IPv6 DHCP: Configuring domain name

*Oct 24 00:51:46.009: IPv6 DHCP: DHCPv6 changes state from INFORMATION-REQUEST to IDLE (REPLY_RECEIVED) on FastEthernet0/0




FastEthernet0/0 [up/up]



FastEthernet0/1 [up/up]




R2 (Server) :

R2#sh ipv6 dhcp binding

R2#sh ipv6 dhcp data

R2#sh ipv6 dhcp interface

FastEthernet0/1 is in server mode

Using pool: SLAAC-POOL

Preference value: 0

Hint from client: ignored

Rapid-Commit: enabled


R2#sh ipv6 dhcp pool


DNS server: XXXX:YYYY:8B6B:90E0::57

DNS server: 2001:DB8::57

Domain name:

Active clients: 0


Note the DHCPv6 provides only DNS and domain name information, no IPv6 address assignment

Picture3: DHCP information request

Picture4: DHCP information reply


Picture5: ICMPv6 flow between DHCPv6 server and client interfaces:


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One Response to Stateless DHCPv6 + SLAAC [2/4]

  1. Pingback: IOS DHCPv6 deployment schemes « CCIE, the beginning!

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