[Dnsmasq-discuss] Problem when system has both hardwired and wireless connections

[Simon Kelley]

On 03/10/13 15:11, Chris Green wrote:
> On Thu, Oct 03, 2013 at 02:58:23PM +0100, Simon Kelley wrote:
>> On 03/10/13 14:38, Chris Green wrote:
>>> I have just noticed that my system running dnsmasq keeps repeating this
>>> sequence in syslog:-
>>>
>>>      Oct  3 14:33:47 revo dhclient: DHCPREQUEST of 192.168.1.148 on wlan0 to 192.168.1.2 port 67
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 available DHCP range:
>> 192.168.1.80 -- 192.168.1.150
>>>      Oct  3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 client provides name: revo
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 DHCPREQUEST(lo) 192.168.1.148
>> 00:25:56:1f:ba:69
>>>      Oct  3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 tags: lo
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 DHCPACK(lo) 192.168.1.148
>> 00:25:56:1f:ba:69 revo
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 requested options:
>> 1:netmask, 28:broadcast, 2:time-offset, 3:router,
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 requested options:
>> 15:domain-name, 6:dns-server, 119:domain-search,
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 requested options:
>> 12:hostname, 44:netbios-ns, 47:netbios-scope,
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 requested options:
>> 26:mtu, 121:classless-static-route, 42:ntp-server,
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 requested options:
>> 121:classless-static-route, 249, 252, 42:ntp-server
>>>      Oct  3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 next server: 192.168.1.2
>>>      Oct  3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 sent size:  1 option: 53 message-type  5
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 sent size: 4 option:
>> 54 server-identifier 192.168.1.2
>>>      Oct  3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 sent size:  4 option: 51 lease-time  1h
>>>      Oct  3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 sent size:  4 option: 58 T1  27m30s
>>>      Oct  3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 sent size:  4 option: 59 T2  50m
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 sent size: 4 option:
>> 1 netmask 255.255.255.0
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 sent size: 4 option:
>> 28 broadcast 192.168.1.255
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 sent size: 4 option:
>> 6 dns-server 192.168.1.2
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 sent size: 7 option:
>> 15 domain-name zbmc.eu
>>>      Oct  3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 sent size:  4 option: 12 hostname  revo
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: 1192620333 sent size: 4 option:
>> 3 router 192.168.1.1
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: not giving name revo.zbmc.eu
>> to the DHCP lease of 192.168.1.148 because the name exists in /etc/hosts
>>
>>>      with address 192.168.1.2
>>> Oct 3 14:33:47 revo dnsmasq-dhcp[3989]: not giving name revo to the DHCP
>> lease of 192.168.1.148 because the name exists in /etc/hosts with
>>>      address 192.168.1.2
>>>
>>> Is there any simple way to stop it doing this - apart from turning the
>>> wireless off?
>>>
>>
>> What do you want to achieve?  having revo.zbmc.eu resolve to both
>> wired and wireless addresses, or just suppressing the warnings?
>>
> Hmm, that's a good question!  :-)
>
> revo.zbmc.eu is the server machine on my network which runs dnsmasq and
> has the following in its /etc/hosts file:-
>
>      192.168.1.1 vigor 2820n
>      192.168.1.2 revo dns
>      192.168.1.4 chris zbmc.eu
>      192.168.1.5 maxinexp
>      192.168.1.6 ben
>      192.168.13.254 2wire BT2700HGV gateway.2wire.net
>
> The ideal would be that if the hardwired connection to 192.168.1.2 fails
> then revo.zbmc.eu would still be available as DNS server via its
> wireless connection.  Can it be set up to provide two DNS addresses to
> DHCP clients with one being the existing hardwired one and the other
> being the wireless one?  The wireless connection can obviously have a
> different name like revowifi but I'm not quite clear how to do the rest.
>
>
Hmm, I'm assuming that DHCP requests on your wireless network somehow 
get back to the wired network on revo?

OK, avoid the warning, the easiest thing to do is to fix the config of 
dhclient on revo to not send a hostname.

Actually, scratch that: the easiest thing to do is give the wlan 
interface on revo a static IP address, in the same way you've done with 
the wired interface, then configure dnsmasq to send both addresses

dhcp-option=6, <ip address of revo-wired>,<ip address of revo-wireless>


Simon.