[Dnsmasq-discuss] Help with dnsmasq and vlans tags

john doe johndoe65534 at mail.com
Tue Dec 4 15:26:46 GMT 2018


On 12/4/2018 12:02 PM, jmperrote wrote:
> El 2018-12-03 13:30, john doe escribió:
>> On 12/3/2018 4:27 PM, jmperrote wrote:
>>> We need help to configure dnsmasq with vlans tagged on router.
>>>
>>> We actually have a dnsmasq server serving dns and dhcp, and 3 nics, one
>>> for each vlans:
>>>
>>> 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:eth0,set:VLAN_137,10.11.137.90,10.11.137.98,6h
>>> 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,10.11.137.1 # gateway
>>>
>>> dhcp-range=interface:eth0,set:VLAN_237,10.11.237.50,10.11.237.200,6h
>>> 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,10.11.237.1 # gateway
>>>
>>>
>>> Know we are migratting to a dnsmasq solution with one nic a tagged
>>> vlans: But the result is not that we want:
>>>
>>> We configure this:
>>>
>>> dhcp-range=tag:vlan37,set:VLAN_37,10.11.37.50,10.11.37.200,6h
>>> dhcp-range=tag:vlan137,set:VLAN_137,10.11.137.50,10.11.137.200,6h
>>> dhcp-range=tag:vlan237,set:VLAN_237,10.11.237.50,10.11.237.200,6h
>>> dhcp-option=tag:vlan37,option:dns-server,10.11.37.15
>>> dhcp-option=tag:vlan137,option:dns-server,10.11.37.15
>>> dhcp-option=tag:vlan237,option:dns-server,10.11.37.15
>>> dhcp-option=tag:vlan137,option:router,10.11.137.1
>>> dhcp-option=tag:vlan37,option:router,10.11.37.1
>>> dhcp-option=tag:vlan237,option:router,10.11.237.1
>>>
>>> But all clients recive allways the same gateway, 10.11.237.1
>>>
>>
>> I'm not sure to fully understand the issue(s) you are facing.
>> As far as dnsmasq is concerned, there is no differences between 3
>> physical "nicks" and 3 VLAN tagged interfaces  (802.1Q).
>> So for a start you could simply try:
>>
>> # Specify DHCP range with a tag
>> dhcp-range=set:vlan99,172.23.100.200,172.23.100.230,12h
>> dhcp-range=set:vlan100,172.23.101.200,172.23.101.230,12h
>> dhcp-range=set:vlan100,172.23.102.200,172.23.102.230,12h
> 
> 
>  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.

-- 
John Doe



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