IPv6 DHCP on a Cisco 1800?

[Ronni Feldt]

I have made a small IPv6 network using my Cisco 1812 (12.4(15)T17).

-------------------- CONFIGURATION --------------------
!
ipv6 unicast-routing
ipv6 cef
!
ipv6 dhcp pool VLAN10
 prefix-delegation pool VLAN10 lifetime infinite infinite
 dns-server 2001:4860:4860::8888
 dns-server 2001:4860:4860::8844
 domain-name d5.int
!
!
interface Tunnel0
 description Hurricane Electric IPv6 Tunnel Broker
 no ip address
 ipv6 address <prefix>::2/64
 ipv6 enable
 tunnel source y.y.y.y
 tunnel destination h.h.h.h
 tunnel mode ipv6ip
!
interface FastEthernet0
 ip address dhcp
 ip access-group acl in
 ip nat outside
 ip virtual-reassembly
 duplex auto
 speed auto
 no cdp enable
!
interface Vlan10
 description CLIENTS
 ip address x.x.x.x m.m.m.m
 no ip proxy-arp
 ip nat inside
 ip virtual-reassembly
 ipv6 address <prefix>:10::1/64
 ipv6 enable
 ipv6 mtu 1280
 ipv6 nd other-config-flag
 ipv6 dhcp server VLAN10
 ipv6 virtual-reassembly
!
!
ipv6 route ::/0 Tunnel0
ipv6 local pool VLAN10 <prefix>:10::/64 64
!
-------------------------------------------------------

The first time I configured a DHCP address on my Linux it got an IPv6 address; all tries after a reboot fails.
Windows got an IPv6 address, after restart all tries fails.

Debug output:
# debug ipv6 dhcp detail

-------------------- DEBUG --------------------
May 30 12:12:31.392: IPv6 DHCP: Received SOLICIT from FE80::3473:7E72:C34F:3170 on Vlan10
May 30 12:12:31.392: IPv6 DHCP: detailed packet contents
May 30 12:12:31.392:   src FE80::3473:7E72:C34F:3170 (Vlan10)
May 30 12:12:31.392:   dst FF02::1:2
May 30 12:12:31.392:   type SOLICIT(1), xid 4823206
May 30 12:12:31.392:   option ELAPSED-TIME(8), len 2
May 30 12:12:31.392:     elapsed-time 0
May 30 12:12:31.392:   option CLIENTID(1), len 14
May 30 12:12:31.392:     000100011936CCAC3C970E510213
May 30 12:12:31.392:   option IA-NA(3), len 12
May 30 12:12:31.392:     IAID 0x18247703, T1 0, T2 0
May 30 12:12:31.392:   option UNKNOWN(39), len 23
May 30 12:12:31.392:   option VENDOR-CLASS(16), len 14
May 30 12:12:31.392:   option ORO(6), len 8
May 30 12:12:31.392:     DOMAIN-LIST,DNS-SERVERS,VENDOR-OPTS,UNKNOWN
May 30 12:12:31.392: IPv6 DHCP: Option IA-NA(3) is not supported yet
May 30 12:12:31.392: IPv6 DHCP: Sending ADVERTISE to FE80::3473:7E72:C34F:3170 on Vlan10
May 30 12:12:31.392: IPv6 DHCP: detailed packet contents
May 30 12:12:31.392:   src FE80::217:95FF:FE4E:57E4
May 30 12:12:31.392:   dst FE80::3473:7E72:C34F:3170 (Vlan10)
May 30 12:12:31.392:   type ADVERTISE(2), xid 4823206
May 30 12:12:31.392:   option SERVERID(2), len 10
May 30 12:12:31.392:     000300010017954E57E4
router#
May 30 12:12:31.392:   option CLIENTID(1), len 14
May 30 12:12:31.392:     000100011936CCAC3C970E510213
May 30 12:12:31.392:   option STATUS-CODE(13), len 15
May 30 12:12:31.392:     status code NOADDRS-AVAIL(2)
May 30 12:12:31.392:     status message: NOADDRS-AVAIL
May 30 12:12:32.392: IPv6 DHCP: Received SOLICIT from FE80::3473:7E72:C34F:3170 on Vlan10
May 30 12:12:32.392: IPv6 DHCP: detailed packet contents
May 30 12:12:32.392:   src FE80::3473:7E72:C34F:3170 (Vlan10)
May 30 12:12:32.392:   dst FF02::1:2
May 30 12:12:32.392:   type SOLICIT(1), xid 4823206
May 30 12:12:32.392:   option ELAPSED-TIME(8), len 2
May 30 12:12:32.392:     elapsed-time 100
May 30 12:12:32.392:   option CLIENTID(1), len 14
May 30 12:12:32.392:     000100011936CCAC3C970E510213
May 30 12:12:32.392:   option IA-NA(3), len 12
May 30 12:12:32.392:     IAID 0x18247703, T1 0, T2 0
May 30 12:12:32.392:   option UNKNOWN(39), len 23
May 30 12:12:32.392:   option VENDOR-CLASS(16), len 14
May 30 12:12:32.392:   option ORO(6), len 8
May 30 12:12:32.392:     DOMAIN-LIST,DNS-SERVERS,VENDOR-OPTS,UNKNOWN
May 30 12:12:32.392: IPv6 DHCP: Option IA-NA(3) is not supported yet
May 30 12:12:32.392: IPv6 DHCP: Sending ADVERTISE to FE80::3473:7E72:C34F:3170 on Vlan10
May 30 12:12:32.392: IPv6 DHCP: detailed packet contents
May 30 12:12:32.392:   src FE80::217:95FF:FE4E:57E4
May 30 12:12:32.392:   dst FE80::3473:7E72:C34F:3170 (Vlan10)
May 30 12:12:32.392:   type ADVERTISE(2), xid 4823206
May 30 12:12:32.392:   option SERVERID(2), len 10
May 30 12:12:32.392:     000300010017954E57E4
router#
May 30 12:12:32.392:   option CLIENTID(1), len 14
May 30 12:12:32.392:     000100011936CCAC3C970E510213
May 30 12:12:32.392:   option STATUS-CODE(13), len 15
May 30 12:12:32.392:     status code NOADDRS-AVAIL(2)
May 30 12:12:32.392:     status message: NOADDRS-AVAIL
--------------------------------------------------------------------------------

The last two entries:
May 30 12:12:32.392:     status code NOADDRS-AVAIL(2)
May 30 12:12:32.392:     status message: NOADDRS-AVAIL

Says that theres no addresses available?

Do I miss something in my configuration?

A lot of the documentation and examples on the internet uses the command:
# ipv6 dhcp pool SOME_POOL
 address ...

But I don't have this command.

Anyone knows how to get this working?

[Peter Paluch · Accepted solution]

Ronni,

Unfortunately, the support for the usual DHCPv6 address assignments was only added in IOS 12.4(24)T with the address prefix command.

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipv6/command/ipv6-cr-book/ipv6-a1.html#wp2812007540

Without this command, your DHCP server will not be able to assign individual addresses to clients. The prefix delegation you have configured is a different, unrelated feature which you should remove from your configuration. Your DHCP server should be currently capable of assigning supplementary configuration to your clients such as DNS, domain names, etc., but the address itself will need to be obtained via SLAAC rather than through DHCPv6. Your router appears to be configured correctly in that it tells the stations to get their address via SLAAC and other configuration via DHCPv6 but these two flags (Managed flag, Other config flag) may not be always properly honored by the clients.

So what I suggest doing is removing the prefix-delegation command from your current DHCPv6 pool, and trying again. Keep in mind that the client addresses will have to be obtained via SLAAC. If this does not work then you may need to upgrade the IOS.

Best regards,
Peter