[Dnsmasq-discuss] Clarification of prefix length field in dhcp-range

Kevin Darbyshire-Bryant kevin at darbyshire-bryant.me.uk
Sat Oct 5 14:21:26 BST 2013


Hi All,

dnsmasq2.67rc3 - possibly odd behaviour, probably I misunderstand :-)

I have an interface that has a /64 on it.  dnsmasq.conf has amongst
other things
"
dhcp-range=::100, ::F:FFFF:FFFF, constructor:br0, ra-names, 64, 12h
enable-ra
"

This picks up the /64 prefix, allocates a DHCPv6 range and basically
works as I would expect.  In theory the ', 64' in the line is redundant.

Now, if I change said interface to be a /48 (restarting dnsmasq), the
logfile says it's built a constructed range as before, but it no longer
does RA and in fact DHCPv6 requests get rebuffed with a 'no valid
range'.  Shouldn't the ', 64' force this to behave as a /64 for the
constructed range?  And shouldn't it do RA?

Many thanks,

Kevin


Non working logfile extract (so with a /48 on br0 interface)

Oct  4 19:41:26 Router daemon.info dnsmasq[4518]: started, version
2.67rc3-38-gfbc150d cachesize 1500
Oct  4 19:41:26 Router daemon.info dnsmasq[4518]: compile time options:
IPv6 GNU-getopt no-RTC no-DBus no-i18n no-IDN DHCP DHCPv6 no-Lua TFTP
no-conntrack ipset Tomato-helper auth
Oct  4 19:41:26 Router daemon.warn dnsmasq[4518]: warning: interface
ppp9 does not currently exist
Oct  4 19:41:26 Router daemon.warn dnsmasq[4518]: warning: interface
ppp8 does not currently exist
Oct  4 19:41:26 Router daemon.warn dnsmasq[4518]: warning: interface
ppp7 does not currently exist
Oct  4 19:41:26 Router daemon.warn dnsmasq[4518]: warning: interface
ppp6 does not currently exist
Oct  4 19:41:26 Router daemon.warn dnsmasq[4518]: warning: interface
ppp5 does not currently exist
Oct  4 19:41:26 Router daemon.warn dnsmasq[4518]: warning: interface
ppp4 does not currently exist
Oct  4 19:41:26 Router daemon.info dnsmasq[4518]: asynchronous logging
enabled, queue limit is 5 messages
Oct  4 19:41:26 Router daemon.info dnsmasq-dhcp[4518]: DHCP, IP range
192.168.235.21 -- 192.168.235.254, lease time 12h
Oct  4 19:41:26 Router daemon.info dnsmasq-dhcp[4518]: DHCPv6, IP range
::100 -- ::f:ffff:ffff, lease time 12h, template for br0
Oct  4 19:41:26 Router daemon.info dnsmasq-dhcp[4518]: DHCPv4-derived
IPv6 names on br0
Oct  4 19:41:26 Router daemon.info dnsmasq-dhcp[4518]: router
advertisement on br0
Oct  4 19:41:26 Router daemon.info dnsmasq-dhcp[4518]: DHCPv6, IP range
2001:470:6b99::100 -- 2001:470:6b99::f:ffff:ffff, lease time 12h,
constructed for br0
Oct  4 19:41:26 Router daemon.info dnsmasq-dhcp[4518]: DHCPv4-derived
IPv6 names on 2001:470:6b99::, constructed for br0
Oct  4 19:41:26 Router daemon.info dnsmasq-dhcp[4518]: router
advertisement on 2001:470:6b99::, constructed for br0
Oct  4 19:41:26 Router daemon.info dnsmasq[4518]: using local addresses
only for domain internal
Oct  4 19:41:26 Router daemon.info dnsmasq[4518]: reading
/etc/resolv.dnsmasq
Oct  4 19:41:26 Router daemon.info dnsmasq[4518]: using nameserver
90.207.238.99#53
Oct  4 19:41:26 Router daemon.info dnsmasq[4518]: using nameserver
90.207.238.97#53
Oct  4 19:41:26 Router daemon.info dnsmasq[4518]: using nameserver
2001:470:20::2#53
Oct  4 19:41:26 Router daemon.info dnsmasq[4518]: using local addresses
only for domain internal
Oct  4 19:41:27 Router daemon.info dnsmasq[4518]: read /etc/hosts - 4
addresses
Oct  4 19:41:27 Router daemon.info dnsmasq[4518]: read
/etc/dnsmasq/hosts/hosts - 30 addresses
Oct  4 19:41:27 Router daemon.info dnsmasq-dhcp[4518]: read
/etc/dnsmasq/dhcp/dhcp-hosts
Oct  4 19:41:28 Router daemon.info dnsmasq-dhcp[4518]: DHCPREQUEST(br0)
192.168.235.130 ac:3c:0b:0c:e7:fd
Oct  4 19:41:28 Router daemon.info dnsmasq-dhcp[4518]: DHCPACK(br0)
192.168.235.130 ac:3c:0b:0c:e7:fd Kevins-iPad
Oct  4 19:41:28 Router daemon.info dnsmasq-dhcp[4518]: DHCPREQUEST(br0)
192.168.235.139 a0:ed:cd:ca:69:c6
Oct  4 19:41:28 Router daemon.info dnsmasq-dhcp[4518]: DHCPACK(br0)
192.168.235.139 a0:ed:cd:ca:69:c6 Kevins-iPhone-5
Oct  4 19:41:31 Router daemon.info dnsmasq-dhcp[4518]: RTR-SOLICIT(br0)
ac:3c:0b:0c:e7:fd
Oct  4 19:41:32 Router daemon.info dnsmasq-dhcp[4518]: RTR-SOLICIT(br0)
a0:ed:cd:ca:69:c6
Oct  4 19:41:33 Router daemon.warn dnsmasq-dhcp[4518]: no address range
available for DHCPv6 request via br0
Oct  4 19:41:35 Router daemon.info dnsmasq-dhcp[4518]: DHCPREQUEST(br0)
192.168.235.235 24:77:03:47:8f:ec
Oct  4 19:41:35 Router daemon.info dnsmasq-dhcp[4518]: DHCPACK(br0)
192.168.235.235 24:77:03:47:8f:ec Animal
Oct  4 19:41:35 Router daemon.warn dnsmasq-dhcp[4518]: no address range
available for DHCPv6 request via br0
Oct  4 19:41:36 Router daemon.info dnsmasq-dhcp[4518]: RTR-SOLICIT(br0)
ac:3c:0b:0c:e7:fd
Oct  4 19:41:36 Router daemon.info dnsmasq-dhcp[4518]: RTR-SOLICIT(br0)
24:77:03:47:8f:ec
Oct  4 19:41:39 Router daemon.warn dnsmasq-dhcp[4518]: no address range
available for DHCPv6 request via br0
Oct  4 19:41:40 Router daemon.info dnsmasq-dhcp[4518]: RTR-SOLICIT(br0)
24:77:03:47:8f:ec
Oct  4 19:41:47 Router daemon.warn dnsmasq-dhcp[4518]: no address range
available for DHCPv6 request via br0

Working (with /64)

Oct  5 14:06:10 Router daemon.info dnsmasq[17194]: started, version
2.67rc3-38-gfbc150d cachesize 1500
Oct  5 14:06:10 Router daemon.info dnsmasq[17194]: compile time options:
IPv6 GNU-getopt no-RTC no-DBus no-i18n no-IDN DHCP DHCPv6 no-Lua TFTP
no-conntrack ipset Tomato-helper auth
Oct  5 14:06:10 Router daemon.warn dnsmasq[17194]: warning: interface
ppp9 does not currently exist
Oct  5 14:06:10 Router daemon.warn dnsmasq[17194]: warning: interface
ppp8 does not currently exist
Oct  5 14:06:10 Router daemon.warn dnsmasq[17194]: warning: interface
ppp7 does not currently exist
Oct  5 14:06:10 Router daemon.warn dnsmasq[17194]: warning: interface
ppp6 does not currently exist
Oct  5 14:06:10 Router daemon.warn dnsmasq[17194]: warning: interface
ppp5 does not currently exist
Oct  5 14:06:10 Router daemon.warn dnsmasq[17194]: warning: interface
ppp4 does not currently exist
Oct  5 14:06:10 Router daemon.info dnsmasq[17194]: asynchronous logging
enabled, queue limit is 5 messages
Oct  5 14:06:10 Router daemon.info dnsmasq-dhcp[17194]: DHCP, IP range
192.168.235.21 -- 192.168.235.254, lease time 12h
Oct  5 14:06:10 Router daemon.info dnsmasq-dhcp[17194]: DHCPv6, IP range
::100 -- ::f:ffff:ffff, lease time 12h, template for br0
Oct  5 14:06:10 Router daemon.info dnsmasq-dhcp[17194]: DHCPv4-derived
IPv6 names on br0
Oct  5 14:06:10 Router daemon.info dnsmasq-dhcp[17194]: router
advertisement on br0
Oct  5 14:06:10 Router daemon.info dnsmasq-dhcp[17194]: DHCPv6, IP range
2001:470:6b99:da2b::100 -- 2001:470:6b99:da2b::f:ffff:ffff, lease time
12h, constructed for br0
Oct  5 14:06:10 Router daemon.info dnsmasq-dhcp[17194]: DHCPv4-derived
IPv6 names on 2001:470:6b99:da2b::, constructed for br0
Oct  5 14:06:10 Router daemon.info dnsmasq-dhcp[17194]: router
advertisement on 2001:470:6b99:da2b::, constructed for br0
Oct  5 14:06:10 Router daemon.info dnsmasq-dhcp[17194]: RTR-ADVERT(br0)
2001:470:6b99:da2b::
Oct  5 14:06:10 Router daemon.info dnsmasq-dhcp[17194]: IPv6 router
advertisement enabled
Oct  5 14:06:10 Router daemon.info dnsmasq[17194]: using local addresses
only for domain internal
Oct  5 14:06:10 Router daemon.info dnsmasq[17194]: reading
/etc/resolv.dnsmasq
Oct  5 14:06:10 Router daemon.info dnsmasq[17194]: using nameserver
90.207.238.99#53
Oct  5 14:06:10 Router daemon.info dnsmasq[17194]: using nameserver
90.207.238.97#53
Oct  5 14:06:10 Router daemon.info dnsmasq[17194]: using nameserver
2001:470:20::2#53
Oct  5 14:06:10 Router daemon.info dnsmasq[17194]: using local addresses
only for domain internal
Oct  5 14:06:10 Router daemon.info dnsmasq[17194]: read /etc/hosts - 4
addresses
Oct  5 14:06:10 Router daemon.info dnsmasq[17194]: read
/etc/dnsmasq/hosts/hosts - 30 addresses
Oct  5 14:06:10 Router daemon.info dnsmasq-dhcp[17194]: read
/etc/dnsmasq/dhcp/dhcp-hosts
Oct  5 14:06:10 Router daemon.info dnsmasq-dhcp[17194]: RTR-ADVERT(br0)
2001:470:6b99:da2b::
Oct  5 14:06:25 Router daemon.info dnsmasq-dhcp[17194]: RTR-ADVERT(br0)
2001:470:6b99:da2b::
Oct  5 14:06:36 Router daemon.info dnsmasq-dhcp[17194]: RTR-ADVERT(br0)
2001:470:6b99:da2b::
Oct  5 14:06:47 Router daemon.info dnsmasq-dhcp[17194]: RTR-ADVERT(br0)
2001:470:6b99:da2b::
Oct  5 14:07:01 Router daemon.info dnsmasq-dhcp[17194]: RTR-ADVERT(br0)
2001:470:6b99:da2b::
Oct  5 14:07:12 Router daemon.info dnsmasq-dhcp[17194]: RTR-ADVERT(br0)
2001:470:6b99:da2b::
Oct  5 14:18:43 Router daemon.info dnsmasq-dhcp[17194]: DHCPCONFIRM(br0)
00:01:00:01:16:a2:0a:60:f0:de:f1:be:f5:48
Oct  5 14:18:43 Router daemon.info dnsmasq-dhcp[17194]: DHCPREPLY(br0)
2001:470:6b99:da2b::4da7:6688 00:01:00:01:16:a2:0a:60:f0:de:f1:be:f5:48
Oct  5 14:18:46 Router daemon.info dnsmasq-dhcp[17194]: RTR-SOLICIT(br0)
24:77:03:47:8f:ec
Oct  5 14:18:46 Router daemon.info dnsmasq-dhcp[17194]: RTR-ADVERT(br0)
2001:470:6b99:da2b::
Oct  5 14:18:47 Router daemon.info dnsmasq-dhcp[17194]: DHCPREQUEST(br0)
192.168.235.235 24:77:03:47:8f:ec
Oct  5 14:18:47 Router daemon.info dnsmasq-dhcp[17194]: DHCPACK(br0)
192.168.235.235 24:77:03:47:8f:ec Animal

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 3768 bytes
Desc: S/MIME Cryptographic Signature
URL: <http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/attachments/20131005/904adf66/attachment.bin>


More information about the Dnsmasq-discuss mailing list