[Dnsmasq-discuss] How to pin IP range on an interface?

bln 77 bln_77 at yahoo.de
Thu Nov 7 06:42:42 GMT 2019



> Am 05.11.2019 um 22:31 schrieb Geert Stappers <stappers at stappers.nl>:
> 
> On Tue, Nov 05, 2019 at 01:26:55PM -0600, Lonnie Abelbeck wrote:
>>> On Nov 5, 2019, at 12:39 PM, bln 77 <bln_77 at yahoo.de> wrote:
>>> 
>>> Hi everyone,
>>> 
>>> I have a 10.1.0.0/16 network.
>>> I want to have clients in the same network because I want to be able to receive IP-broadcast for autodiscovery.
>>> I configured two VLANs and the router has an interface/ip in both:
>>> lan1: 10.1.1.0 with subnet mask 255.255.0.0
>>> lan2: 10.1.2.0 with subnet mask 255.255.0.0
>>> 
>>> Both interfaces are bridged together and I filter/firewall the traffic with etables rules.
>>> I have a filter that blocks DHCP traffic from being bridged/forwarded.
>>> 
>>> Now I want to configure dnsmasq to offer the following ranges on the interfaces so I can easily recognise in which net the client belongs:
>>> 
>>> dhcp-range=set:lan1,10.1.1.50,10.1.2.199,255.255.0.0,12h
>>> dhcp-range=set:lan2,10.1.2.50,10.1.3.199,255.255.0.0,12h
>>> 
>>> Unfortunately the clients on the second interface also getting an offer from the 10.1.1.x range.
>>> 
>>> I think both ranges are active on both interfaces?
>>> 
>>> Is there any way to pin a range to an interface?
>>> 
>>> Any help is appreciated.
>> 
>> Alternatively, use isolated subnets with 255.255.255.0 masks, no bridge, and enable "avahi-daemon" to share the broadcasts you need between subnets.
>> 
>> Everything is now simple ... except possibly configuring "avahi-daemon". :-)
>> 
> 
> Here another person that doesn't understand the use case of O.P.
> 
> But I think the question is
>>> Is there any way to pin a range to an interface?
> 
> 
> Two snippets from http://thekelleys.org.uk/dnsmasq/docs/dnsmasq-man.html
> 
> 1: The tag "bootp" is set for BOOTP requests, and a tag whose name is the
>   name of the interface on which the request arrived is also set.
> 
> 2: --dhcp-range=[tag:<tag>[,tag:<tag>],][set:<tag>,]<start-addr>
>     [,<end-addr>|<mode>][,<netmask>[,<broadcast>]][,<lease time>]
> 
> 
> Let us, this mailinglist, know how helpfull this posting was.
> 

This helped a lot. Didn’t knew that a tag is set automatically:)

Seems to work now:
dhcp-range=tag:eth0.1,10.1.1.50,10.1.1.199,255.255.0.0,12h
dhcp-range=tag:eth0.2,10.1.2.50,10.1.2.199,255.255.0.0,12h
lan1 and lan2 (openwrt) wasn’t set, instead the “real” name was used by dnsmasq

Thanks.





More information about the Dnsmasq-discuss mailing list