[Dnsmasq-discuss] No dynamic addresses to unknown hosts

Simon Kelley simon at thekelleys.org.uk
Mon Jan 19 16:12:53 GMT 2009


ms at webstollen.de wrote:
>>> dhcp-range=net:meeting,192.168.3.101,192.168.3.200,24h
>>> dhcp-range=net:webstollen,192.168.4.101,192.168.4.200,24h
>>> dhcp-range=net:dockland,192.168.6.101,192.168.6.200,24h
>>>
>> These say "only use the range only when the tag (webstollen, meeting, 
>> dockland) is set. There's no range available for use when none of the 
>> those three tags are set.
>>
>> Since an unknown host will not set those tags, there is no available 
>> range and therefore no available address.
> 
> What do those tags mean? My Windows clients dont't have any tags set and 
> I think that they can't set any. What is the difference between 
> "net:webstollen" and "webstollen" in the lines:
> 
> dhcp-range=net:webstollen,192.168.4.101,192.168.4.200,24h
> dhcp-option=webstollen,3,192.168.4.1
> 
> Don't they mean the same?


There's a useful summary at the end of this:
http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2008q4/002658.html

In general, "net:webstollen" and "webstollen" mean the same thing, BUT 
not in dhcp-range. in dhcp-range, <tag> sets a tag, whilst net:<tag> 
matches it. This is very confusing and really should be re-designed.


> 
> 
>> Which address range do you want unknown clients to be allocated too?
> 
> Depending on the subnet they're in, they should get addresses from the 
> ranges defined above. Example: If an unknown client from subnet 
> 192.168.4.0 requests an address, it should get an address between 
> 192.168.4.101 and 192.168.4.200.
> 

Are your subnets on different physical networks? Until clients get an 
address, there's no way to tell which subnet it's in, that's defined by 
it's address. All you know is which network/broadcast domain it is 
plugged into. Dnsmasq handles addresses based on network (using the 
interface that the request arrived on) automatically.

As long as your VLANS setup is sane, it should just work without needing 
tags at all to do address allocation.


Cheers,

Simon.

> 
> Thanks for your answer, Simon!
> 
> Manfred
> 




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