[Dnsmasq-discuss] Unable to configure stateful prefix length larger than 64

Pablo Rodríguez Fernández morpheus17.pro at gmail.com
Tue Feb 26 17:05:37 GMT 2013


Hi,

I've installed dnsmasq v2.62 and have tried to do the same that is
described on
http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2012q2/005878.html,
being unable to setup a client host with the correct prefix length,
getting always an /64 address.

This is my (dhcpv6 relevant) dnsmasq.conf:
    domain-needed
    dhcp-range=fc00::14, fc00::1f, 124, 5m
    dhcp-option=option6:dns-server,fc00::11
    enable-ra
    log-dhcp

I checked with tcpdump that router sends router advertisements with the
correct prefix-length (unsoliciting or soliciting them with rdisc6):
    16:54:59.200913 IP6 (hlim 255, next-header ICMPv6 (58) payload
length: 8) fe80::219:66ff:fe38:6cf4 > ff02::2: [icmp6 sum ok] ICMP6,
router solicitation, length 8
    16:54:59.202489 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58)
payload length: 88) fe80::ba27:ebff:fe93:eafb >
fe80::219:66ff:fe38:6cf4: [icmp6 sum ok] ICMP6, router advertisement,
length 88
        hop limit 64, Flags [managed, other stateful], pref medium,
router lifetime 1800s, reachable time 0s, retrans time 0s
          prefix info option (3), length 32 (4): fc00::10/124, Flags
[none], valid time 7200s, pref. time 7200s
          mtu option (5), length 8 (1):  1500
          source link-address option (1), length 8 (1): b8:27:eb:93:ea:fb
          rdnss option (25), length 24 (3):  lifetime 1800s, addr: fc00::11

server is routing:
    $ sysctl -a | grep forwarding | grep ipv6 | grep -v \.lo
    net.ipv6.conf.all.forwarding = 1
    net.ipv6.conf.default.forwarding = 1
    net.ipv6.conf.eth0.forwarding = 1

and client is configured to accept ra:
    $ sysctl -a | grep accept_ra | grep -v \.lo
    net.ipv6.conf.all.accept_ra = 1
    net.ipv6.conf.all.accept_ra_defrtr = 1
    net.ipv6.conf.all.accept_ra_pinfo = 1
    net.ipv6.conf.all.accept_ra_rtr_pref = 1
    net.ipv6.conf.all.accept_ra_rt_info_max_plen = 0
    net.ipv6.conf.default.accept_ra = 1
    net.ipv6.conf.default.accept_ra_defrtr = 1
    net.ipv6.conf.default.accept_ra_pinfo = 1
    net.ipv6.conf.default.accept_ra_rtr_pref = 1
    net.ipv6.conf.default.accept_ra_rt_info_max_plen = 0
    net.ipv6.conf.eth0.accept_ra = 1
    net.ipv6.conf.eth0.accept_ra_defrtr = 1
    net.ipv6.conf.eth0.accept_ra_pinfo = 1
    net.ipv6.conf.eth0.accept_ra_rtr_pref = 1
    net.ipv6.conf.eth0.accept_ra_rt_info_max_plen = 0

But, when i do
    $ sudo dhclient -6 -1 -v eth0

i get:
    inet6 addr: fc00::18/64 Scope:Global

instead of:
    inet6 addr: fc00::18/124 Scope:Global

I also tried setting net.ipv6.conf.all.autoconf = 0 and others dhcp
client like dibbler-client or dhcp6c (from wide/kame) without success.
I've noticed that any of dhcp client i tried sends router solicitations,
could it be the problem?

Seems that other people
(https://forums.gentoo.org/viewtopic-t-833454-start-0.html) has
successfully assigned prefix length larger than 64 using dhcp+some ra
software (dnsmasq/radvd).

Am i missing something? May it be related to the multiple of 8 prefix
length bug
(http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2012q2/005879.html)
?

Sorry if this shouldn't be answered here, but i don't know where or to
who i should address this question.

Greetings,
Pablo



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