Enable DHCPv6 in dnsmasq to distribute fixed range IPv6 addresses but failed

Question

Help wanted! I want to create a AP in my Raspbian PI. And i choose dnsmasq as the dhcpv4 and dhcpv6 server. However, my laptop can acquire IPv4 successfully but fail to get a IPv6. Why the dnsmasq doesn't work for IPv6?

# my dnsmasq.conf
domain-needed
no-resolv
no-poll
server=8.8.8.8
server=8.8.4.4
all-servers
interface=wlan0
dhcp-range=192.168.233.100, 192.168.233.200, 255.255.255.0, 12h
dhcp-range=fec0::ff00, fec0::fffe/10, 12h
enable-ra
dhcp-option-force=26,1397
log-queries
log-dhcp
conf-dir=/etc/dnsmasq.d

# glance at the dnsmasq log when i make a DHCP request
hostapd: wlan0: STA 88:53:2e:65:8c:a4 IEEE 802.11: associated
hostapd: wlan0: STA 88:53:2e:65:8c:a4 RADIUS: starting accounting session 56703A6F-00000010
hostapd: wlan0: STA 88:53:2e:65:8c:a4 WPA: pairwise key handshake completed (RSN)
dnsmasq-dhcp[3585]: 2738259568 available DHCP range: 192.168.233.100 -- 192.168.233.200
dnsmasq-dhcp[3585]: 2738259568 client provides name: anri
dnsmasq-dhcp[3585]: 2738259568 DHCPREQUEST(wlan0) 192.168.233.200 88:53:2e:65:8c:a4
dnsmasq-dhcp[3585]: 2738259568 tags: wlan0
dnsmasq-dhcp[3585]: 2738259568 DHCPACK(wlan0) 192.168.233.200 88:53:2e:65:8c:a4 anri
dnsmasq-dhcp[3585]: 2738259568 requested options: 1:netmask, 28:broadcast, 2:time-offset, 3:router,
dnsmasq-dhcp[3585]: 2738259568 requested options: 15:domain-name, 6:dns-server, 119:domain-search,
dnsmasq-dhcp[3585]: 2738259568 requested options: 12:hostname, 44:netbios-ns, 47:netbios-scope,
dnsmasq-dhcp[3585]: 2738259568 requested options: 26:mtu, 121:classless-static-route, 42:ntp-server,
dnsmasq-dhcp[3585]: 2738259568 requested options: 121:classless-static-route, 249, 33:static-route,
dnsmasq-dhcp[3585]: 2738259568 requested options: 252, 42:ntp-server
dnsmasq-dhcp[3585]: 2738259568 next server: 192.168.233.254
dnsmasq-dhcp[3585]: 2738259568 sent size:  1 option: 53 message-type  5
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option: 54 server-identifier  192.168.233.254
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option: 51 lease-time  43200
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option: 58 T1  21600
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option: 59 T2  37800
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option:  1 netmask  255.255.255.0
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option: 28 broadcast  192.168.233.255
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option:  3 router  192.168.233.254
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option:  6 dns-server  192.168.233.254
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option: 12 hostname  anri
dnsmasq-dhcp[3585]: 2738259568 sent size:  2 option: 26 mtu  1397
dnsmasq-dhcp[3585]: RTR-SOLICIT(wlan0)
dnsmasq-dhcp[3585]: 2738259568 available DHCP range: 192.168.233.100 -- 192.168.233.200
dnsmasq-dhcp[3585]: 2738259568 client provides name: anri
dnsmasq-dhcp[3585]: 2738259568 DHCPREQUEST(wlan0) 192.168.233.200 88:53:2e:65:8c:a4
dnsmasq-dhcp[3585]: 2738259568 tags: wlan0
dnsmasq-dhcp[3585]: 2738259568 DHCPACK(wlan0) 192.168.233.200 88:53:2e:65:8c:a4 anri
dnsmasq-dhcp[3585]: 2738259568 requested options: 1:netmask, 28:broadcast, 2:time-offset, 3:router,
dnsmasq-dhcp[3585]: 2738259568 requested options: 15:domain-name, 6:dns-server, 119:domain-search,
dnsmasq-dhcp[3585]: 2738259568 requested options: 12:hostname, 44:netbios-ns, 47:netbios-scope,
dnsmasq-dhcp[3585]: 2738259568 requested options: 26:mtu, 121:classless-static-route, 42:ntp-server,
dnsmasq-dhcp[3585]: 2738259568 requested options: 121:classless-static-route, 249, 33:static-route,
dnsmasq-dhcp[3585]: 2738259568 requested options: 252, 42:ntp-server
dnsmasq-dhcp[3585]: 2738259568 next server: 192.168.233.254
dnsmasq-dhcp[3585]: 2738259568 sent size:  1 option: 53 message-type  5
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option: 54 server-identifier  192.168.233.254
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option: 51 lease-time  43200
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option: 58 T1  21600
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option: 59 T2  37800
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option:  1 netmask  255.255.255.0
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option: 28 broadcast  192.168.233.255
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option:  3 router  192.168.233.254
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option:  6 dns-server  192.168.233.254
dnsmasq-dhcp[3585]: 2738259568 sent size:  4 option: 12 hostname  anri
dnsmasq-dhcp[3585]: 2738259568 sent size:  2 option: 26 mtu  1397

Solution

You are making a few different mistakes in your configuration. First of all site-local addresses have been deprecated for many years. Any documentation telling you to use addresses starting with fec0 is outdated and needs to be updated.

The replacement for site-local addresses is called unique local addresses. These are constructed by using fd as the first octet followed by five random octets. For example you could have fdda:772b:1c61::/48 as your local prefix.

However both types of addresses mentioned above are unsuitable for computers you want to communicate with anything outside your own network. If you want those computers to communicate outside your own network, you should be assigning them addresses from the prefix your ISP have routed to you.

Additionally for many scenarios using DHCPv6 is not the best option. This depends on your specific needs, but often using just a router advertisement daemon (such as radvd) is a more suitable choice than a DHCPv6 server.

Comments

[Ray]

Thanks for the tips. I just want to deploy a LAN with IPv6, so i prefer the local addresses. And DHCPv6 comes to my mind firstly because of it's simple concept. I'll try RA later.

[kasperd]

@Reimondo Router advertisements are simpler and more widely supported than DHCPv6.