[Dnsmasq-discuss] bridged interface gets wrong ip

Simon Kelley simon at thekelleys.org.uk
Sun Dec 30 19:27:00 GMT 2007


Daniel Mierswa wrote:
> hey there
> i don't know a lot about bridging but it seems to me i just got that
> working since gentoo offers a nice way to configure it.
> however i get the wrong ip for my bridge. here's some output.
> 
> $ ip link
> [...]
> 2: eth0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc
> pfifo_fast qlen 1000
>     link/ether 00:17:31:81:08:c8 brd ff:ff:ff:ff:ff:ff
> 8: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
>     link/ether 00:17:31:81:08:c8 brd ff:ff:ff:ff:ff:ff
> 
> $ brctl show
> [...]
> br0             8000.0017318108c8       no              eth0
> 
> $ cat /etc/dnsmasq.conf
> [...]
> dhcp-host=00:17:31:81:08:c8,10.0.0.15 # Istari
> [...]
> 
> $ cat /var/log/dnsmasq
> [...]
> Dec 30 19:53:51 [dnsmasq] DHCPDISCOVER(eth0) 00:17:31:81:08:c8
> Dec 30 19:53:51 [dnsmasq] DHCPOFFER(eth0) 10.0.0.17 00:17:31:81:08:c8
> Dec 30 19:53:51 [dnsmasq] not using configured address 10.0.0.15 because
> it is leased to 00:17:31:81:08:c8
> [...]
> 
> it's either weird or it's me not knowing better but from the output of
> my distribution (gentoo) it seems like dhcpcd is only started once and
> therefore there shouldn't be any conflict about duplicate ip
> [...]
>  * Starting br0
>  *   Creating bridge br0 ...        [ ok ]
>  *   Adding ports to br0
>  *     eth0 ...                     [ ok ]
>  *   Bringing up br0
>  *     dhcp
>  *       Running dhcpcd ...         [ ok ]
>  *       br0 received address 10.0.0.17/24
> [...]
> 
> which is proven with eth0 not showing up on listing ipv4 addresses
> $ ip -4 addr
> [...]
> 8: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
>     inet 10.0.0.17/24 brd 10.0.0.255 scope global br0
> 
> any ideas why i keep getting the wrong ip?
> thanks in advance
> 

My guess is that two interfaces with the same MAC address might be the 
root of the confusion, but I can't explain exactly why. It would be 
useful to see dnsmasq's lease database, in the file 
/var/lib/misc/dnsmasq.leases

Cheers,

Simon.



More information about the Dnsmasq-discuss mailing list