[Dnsmasq-discuss] Help with dnsmasq and vlans tags

Geert Stappers stappers at hendrikx-itc.nl
Wed Dec 5 12:58:31 GMT 2018


On Wed, Dec 05, 2018 at 09:09:25AM -0300, jmperrote wrote:
> El 2018-12-04 12:26, john doe escribió:
> > On 12/4/2018 12:02 PM, jmperrote wrote:
> > > 
> > >  John Doe, sorry for my mistake, my actual configuration of dnsmasq
> > > are:
> > > 
> > >     dhcp-range=interface:eth0,set:VLAN_37,10.11.37.50,10.11.37.200,6h
> > >     dhcp-option=eth0,6,10.11.37.15 #dns primario
> > >     dhcp-option=eth0,1,255.255.255.0 # mascara de red
> > >     dhcp-option=eth0,option:router,10.11.37.1 # gateway
> > > 
> > >     dhcp-range=interface:eth1,set:VLAN_137,10.11.137.90,10.11.137.98,6h
> > >     dhcp-option=eth1,6,10.11.37.15 #dns primario
> > >     dhcp-option=eth1,1,255.255.255.0 # mascara de red
> > >     dhcp-option=eth1,option:router,10.11.137.1 # gateway
> > > 
> > >     dhcp-range=interface:eth2,set:VLAN_237,10.11.237.50,10.11.237.200,6h
> > >     dhcp-option=eth2,6,10.11.37.15 #dns primario
> > >     dhcp-option=eth2,1,255.255.255.0 # mascara de red
> > >     dhcp-option=eth2,option:router,10.11.237.1 # gateway
> > > 
> > > We have 3 nics on the system eth0/eth1/eth2, one for each VLAN, and
> > > try to replace for one nic with VLANs tagged.
> > > 
> > > We try the tag option and the dhcp assign ip on correct range for each
> > > PC on each vlan, but dnsmasq allways assign to the PC the same
> > > gateway, that is the las vlan configured.
> > > 
> > > For example on this configuraton assign the correct range to the PC,
> > > but the gateway always assign 10.11.237.1 gateway, to all PC
> > > 
> > > dhcp-range=interface:eth0.37,set:VLAN_37,10.11.37.90,10.11.37.98,6h
> > > dhcp-option=eth0.37,6,10.11.37.15 #dns primario
> > > dhcp-option=eth0.37,1,255.255.255.0 # mascara de red
> > > dhcp-option=eth0.37,option:router,10.11.37.1 # gateway
> > > 
> > > dhcp-range=interface:eth0.137,set:VLAN_137,10.11.137.90,10.11.137.98,6h
> > > dhcp-option=eth0.137,6,10.11.37.15 #dns primario
> > > dhcp-option=eth0.137,1,255.255.255.0 # mascara de red
> > > dhcp-option=eth0.137,option:router,10.11.137.1 # gateway
> > > 
> > > dhcp-range=interface:eth0.237,set:VLAN_237,10.11.237.50,10.11.237.200,6h
> > > dhcp-option=eth0.237,6,10.11.37.15 #dns primario
> > > dhcp-option=eth0.237,1,255.255.255.0 # mascara de red
> > > dhcp-option=eth0.237,option:router,10.11.237.1 # gateway
> > > 
> > > 
> > > It is necessary to use "vconfig" to configure virtual vlan interface
> > > on the operating system, or can use tagged vlans from the router ?
> > > 
> > 
> > To be able to answer your question I need to know the following:
> > 
> >  - What hardware is the router (netgear, cisco ...)?
> >  - What type of distribution (name and version) are you using 'vconfig'
> > on (Linux, Oracle)?
> > 
> > I can't answer your question without knowing your network topology, but
> > if the router is VLAN tagging capable I would use it and also use the
> > DHCP capability from that router.
> > 
> > Also, to isolate whether it is a vlan configuration or a dnsmasq issue
> > simply try the line I have provided, obviously you can change the Ip
> > ranges to your liking.
> 
> 
> Hello john doe,

Hello Mailinglist,

> 
> Send the data:
>  -- Router mikrotik RB1100 AH
>  -- Ubuntu 16.04
>  -- Using vconfig with 3 VLANs
> 
> Yes, the router have capabilitie to dhcp,
> you recommend to use that instead of dnsmasq for dhcp ?.

What I did read in the reply from john doe:

  Other options might resolve the original problem.


But, yes, it is possible to replace
three NICs with single NIC plus three VLANs.  Surely for DHCP stuff.
If three NICs were choose due high bandwidth usage,
that can't be solved by "VLAN".


Cheers
Geert Stappers




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