[Dnsmasq-discuss] Fwd: Replicate "deny unknown-clients" from dhcpd

[Simon Kelley]

Didster wrote:
> Hi,
> 
> I have been using dnsmasq for a while and it's great.  I am trying to
> install it now on a friends machine who wants to replicate the
> behavior of dhcpd's "deny unknown-clients" for his server.
> 
> I know you can do something like:
> 
> dhcp-range=thelan,192.168.0.20,static,infinite
> 
> And then:
> 
> dhcp-host=01:30:46:51:ca:48,laptop,192.168.0.4
> 
> To allow IPs to be given out to machines that have dhcp-host entires
> (this is what I do) and deny unknown clients.
> 
> But he is not happy having to provide the IP address of each machine.
> Basically, he doesn't want each machines IP to be static, but only
> wants dnsmasq to hand out IPs to machines that have known MAC
> addresses.  You can do this in dhcpd by having "deny unknown-clients"
> and then not having a fixed-address: for each host.
> 
> Is this possiable in dnsmasq?  I have tried removing the IP from the
> dhcp-host lines - I just get "no address available" errors in syslog.
> 
> Is there a solution to this?
> 

You can do this (at least in theory - I've not tested this particular 
configuration.) It's not particularly pretty.


The trick is

dhcp-ignore=#known

which tells dnsmasq to ignore any DHCP request where the tag "known" is 
not set.

Now, for each known host, set the tag

dhcp-host=11:22:33:44:55:66,net:known
dhcp-host=12:34:56:78:70:12,net:known
.
.


and finally, give a DHCP range as normal

dhcp-range=192.168.0.1,192.168.0.100


HTH

Simon.