[Dnsmasq-discuss] DHCPv6

Christof Meerwald cmeerw at cmeerw.org
Mon Apr 8 21:38:29 BST 2013


On Mon, 08 Apr 2013 20:42:25 +0100, Simon Kelley wrote:
> On 08/04/13 19:17, Christof Meerwald wrote:
>> I am afraid I spoke too soon - behaviour seems to be a bit random.
>>
>> So, my dnsmasq configuration is available at
>> http://svn.cmeerw.net/cfg/fruity.cmeerw.net/etc/dnsmasq.conf
[...]
>> Any ideas?
>
> There's at least one possible explanation that doesn't involve a dnsmasq 
> bug, and several that do. The first thing to do is to turn on verbose 
> DHCP logging by adding
>
> log-dhcp
>
> to the config. If we can get log dumps of the same events with that 
> switched on, it will be a lot easier to see what's going on.

Ok, so it seems to depend a bit on the state in dnsmasq.leases. With a
fresh dnsmasq.leases (just containing the duid) it seems to be working
fine:

Apr  8 20:15:34 localhost dnsmasq-dhcp[2749]: 5343413 available DHCP range: 2a01:348:236:feed::d000 -- 2a01:348:236:feed::dfff
Apr  8 20:15:34 localhost dnsmasq-dhcp[2749]: 5343413 DHCPSOLICIT(eth0) 00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb 
Apr  8 20:15:34 localhost dnsmasq-dhcp[2749]: 5343413 DHCPADVERTISE(eth0) 2a01:348:236:feed::13 00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb 
Apr  8 20:15:34 localhost dnsmasq-dhcp[2749]: 5343413 requested options: 24:domain-search, 39:FQDN, 23:dns-server, 
Apr  8 20:15:34 localhost dnsmasq-dhcp[2749]: 5343413 requested options: 31:sntp-server
Apr  8 20:15:34 localhost dnsmasq-dhcp[2749]: 5343413 tags: known, dhcpv6, eth0
Apr  8 20:15:34 localhost dnsmasq-dhcp[2749]: 5343413 sent size: 14 option:  1 client-id  00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb
Apr  8 20:15:34 localhost dnsmasq-dhcp[2749]: 5343413 sent size: 14 option:  2 server-id  00:01:00:01:18:f3:64:29:b8:27:eb:a5:5a:4f
Apr  8 20:15:34 localhost dnsmasq-dhcp[2749]: 5343413 sent size: 40 option:  3 ia-na  IAID=2654529019 T1=3600 T2=6300
Apr  8 20:15:34 localhost dnsmasq-dhcp[2749]: 5343413 nest size: 24 option:  5 iaaddr  2a01:348:236:feed::13 PL=7200 VL=7200
Apr  8 20:15:34 localhost dnsmasq-dhcp[2749]: 5343413 sent size:  9 option: 13 status  0 success
Apr  8 20:15:34 localhost dnsmasq-dhcp[2749]: 5343413 sent size:  1 option:  7 preference  0
Apr  8 20:15:34 localhost dnsmasq-dhcp[2749]: 5343413 sent size: 16 option: 23 dns-server  2a01:348:236:feed::1
Apr  8 20:15:35 localhost dnsmasq-dhcp[2749]: 11311546 available DHCP range: 2a01:348:236:feed::d000 -- 2a01:348:236:feed::dfff
Apr  8 20:15:35 localhost dnsmasq-dhcp[2749]: 11311546 DHCPREQUEST(eth0) 00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb 
Apr  8 20:15:35 localhost dnsmasq-dhcp[2749]: 11311546 DHCPREPLY(eth0) 2a01:348:236:feed::13 00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb 
Apr  8 20:15:35 localhost dnsmasq-dhcp[2749]: 11311546 requested options: 24:domain-search, 39:FQDN, 23:dns-server, 
Apr  8 20:15:35 localhost dnsmasq-dhcp[2749]: 11311546 requested options: 31:sntp-server
Apr  8 20:15:35 localhost dnsmasq-dhcp[2749]: 11311546 tags: known, dhcpv6, eth0
Apr  8 20:15:35 localhost dnsmasq-dhcp[2749]: 11311546 sent size: 14 option:  1 client-id  00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb
Apr  8 20:15:35 localhost dnsmasq-dhcp[2749]: 11311546 sent size: 14 option:  2 server-id  00:01:00:01:18:f3:64:29:b8:27:eb:a5:5a:4f
Apr  8 20:15:35 localhost dnsmasq-dhcp[2749]: 11311546 sent size: 40 option:  3 ia-na  IAID=2654529019 T1=3600 T2=6300
Apr  8 20:15:35 localhost dnsmasq-dhcp[2749]: 11311546 nest size: 24 option:  5 iaaddr  2a01:348:236:feed::13 PL=7200 VL=7200
Apr  8 20:15:35 localhost dnsmasq-dhcp[2749]: 11311546 sent size:  9 option: 13 status  0 success
Apr  8 20:15:35 localhost dnsmasq-dhcp[2749]: 11311546 sent size: 16 option: 23 dns-server  2a01:348:236:feed::1

at this point dnsmasq has been stopped and the client has
(unsuccessfully) tried to release the lease.

dnsmasq has been restarted and the client tries again the get an IPv6
address:

Apr  8 20:17:44 localhost dnsmasq-dhcp[2763]: 10468696 available DHCP range: 2a01:348:236:feed::d000 -- 2a01:348:236:feed::dfff
Apr  8 20:17:44 localhost dnsmasq-dhcp[2763]: 10468696 DHCPSOLICIT(eth0) 00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb 
Apr  8 20:17:44 localhost dnsmasq-dhcp[2763]: 10468696 DHCPADVERTISE(eth0) 2a01:348:236:feed::da3b 00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb 
Apr  8 20:17:44 localhost dnsmasq-dhcp[2763]: 10468696 requested options: 24:domain-search, 39:FQDN, 23:dns-server, 
Apr  8 20:17:44 localhost dnsmasq-dhcp[2763]: 10468696 requested options: 31:sntp-server
Apr  8 20:17:44 localhost dnsmasq-dhcp[2763]: 10468696 tags: known, dhcpv6, eth0
Apr  8 20:17:44 localhost dnsmasq-dhcp[2763]: 10468696 sent size: 14 option:  1 client-id  00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb
Apr  8 20:17:44 localhost dnsmasq-dhcp[2763]: 10468696 sent size: 14 option:  2 server-id  00:01:00:01:18:f3:64:29:b8:27:eb:a5:5a:4f
Apr  8 20:17:44 localhost dnsmasq-dhcp[2763]: 10468696 sent size: 40 option:  3 ia-na  IAID=2654529019 T1=5400 T2=9450
Apr  8 20:17:44 localhost dnsmasq-dhcp[2763]: 10468696 nest size: 24 option:  5 iaaddr  2a01:348:236:feed::da3b PL=10800 VL=10800
Apr  8 20:17:44 localhost dnsmasq-dhcp[2763]: 10468696 sent size:  9 option: 13 status  0 success
Apr  8 20:17:44 localhost dnsmasq-dhcp[2763]: 10468696 sent size:  1 option:  7 preference  0
Apr  8 20:17:44 localhost dnsmasq-dhcp[2763]: 10468696 sent size: 16 option: 23 dns-server  2a01:348:236:feed::1
Apr  8 20:17:45 localhost dnsmasq-dhcp[2763]: 10612472 available DHCP range: 2a01:348:236:feed::d000 -- 2a01:348:236:feed::dfff
Apr  8 20:17:45 localhost dnsmasq-dhcp[2763]: 10612472 DHCPREQUEST(eth0) 00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb 
Apr  8 20:17:45 localhost dnsmasq-dhcp[2763]: 10612472 DHCPREPLY(eth0) 2a01:348:236:feed::da3b 00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb 
Apr  8 20:17:45 localhost dnsmasq-dhcp[2763]: 10612472 requested options: 24:domain-search, 39:FQDN, 23:dns-server, 
Apr  8 20:17:45 localhost dnsmasq-dhcp[2763]: 10612472 requested options: 31:sntp-server
Apr  8 20:17:45 localhost dnsmasq-dhcp[2763]: 10612472 tags: known, dhcpv6, eth0
Apr  8 20:17:45 localhost dnsmasq-dhcp[2763]: 10612472 sent size: 14 option:  1 client-id  00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb
Apr  8 20:17:45 localhost dnsmasq-dhcp[2763]: 10612472 sent size: 14 option:  2 server-id  00:01:00:01:18:f3:64:29:b8:27:eb:a5:5a:4f
Apr  8 20:17:45 localhost dnsmasq-dhcp[2763]: 10612472 sent size: 40 option:  3 ia-na  IAID=2654529019 T1=3600 T2=6300
Apr  8 20:17:45 localhost dnsmasq-dhcp[2763]: 10612472 nest size: 24 option:  5 iaaddr  2a01:348:236:feed::da3b PL=7200 VL=7200
Apr  8 20:17:45 localhost dnsmasq-dhcp[2763]: 10612472 sent size:  9 option: 13 status  0 success
Apr  8 20:17:45 localhost dnsmasq-dhcp[2763]: 10612472 sent size: 16 option: 23 dns-server  2a01:348:236:feed::1

I think I then did a few more release/acquire IPv6 addresses after
that. The dnsmasq.leases now contains:

1365463282 00:26:9e:38:e5:fb 192.168.174.13 twilight *
duid 00:01:00:01:18:f3:64:29:b8:27:eb:a5:5a:4f
1365459684 2654529019 2a01:348:236:feed::da3c * 00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb
1365459335 2147483647 2a01:348:236:feed::13 * 00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb
1365459539 2147483647 2a01:348:236:feed::da3b * 00:01:00:01:18:f3:5c:6c:00:26:9e:38:e5:fb

The IPv4 side looks fine, but the IPv6 entries look a bit strange now...

Hope that helps...


Christof

-- 

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