[Dnsmasq-discuss] Disabling dynamic DHCP assignment for known hosts

Simon Kelley simon at thekelleys.org.uk
Sun Apr 30 18:23:05 BST 2017

I just committed a patch to do this. I chose the tag "known-othernet"
just because it seemed more descriptive.



On 19/04/17 19:36, Todd Sankey wrote:
> I tried a different approach. I created a patch (attached) so that the
> tag "knownother" is applied if there is a host definition that applies
> to a different context. In our setup, we then added
> "dhcp-ignore=tag:knownother".
> On Wed, Mar 15, 2017 at 1:14 PM, Todd Sankey <dev at lutean.com
> <mailto:dev at lutean.com>> wrote:
>     Our setup has two wifi networks with different network addresses,
>     one for employees and one for guests. On the employee network, the
>     hosts all have static host entries that include IP addresses. The
>     guest network has no static host entries. What we would like to do
>     is prevent the employee machines from getting any assignment on the
>     guest network.
>     We tried using "tag:!known" in the dhcp-range configuration, and we
>     have tried a tag-if statement that sets a tag based on the guest
>     network interface and known followed by a dhcp-ignore. Neither works. 
>     Looking through the code, I think it is because when looking for a
>     dhcp_config entry, the search is filtered by whether the assigned
>     address is valid for the interface the request was received on.
>     Since the static assignments are only valid for the employee
>     network, when a request is received on the guest network, the static
>     assignments are not valid so the "known" tag is never set. As a
>     result, neither the dhcp-range tag filter nor the tag-if filter has
>     the desired effect.
>     I next tried having dhcp-host entries for every employee machine,
>     one with a static assignment on the employee network, and one with a
>     static assignment on guest network and appending "ignore" to the
>     guest network entry. This seems to have the desired behaviour in
>     that employee machines cannot get on the guest network. However,
>     this obviously doubles the work of maintaining the host list. I am
>     also not sure what this does to the guest address range having these
>     static but ignored assignments.
>     Is there a better way to do this in the current version (2.76)?
>     If not, would it be a reasonable feature request to extend the
>     handling of dhcp-host settings so that if there is an IP assignment
>     and "ignore" is specified, then the host is ignored on networks
>     where the IP assignment is not valid?
> _______________________________________________
> Dnsmasq-discuss mailing list
> Dnsmasq-discuss at lists.thekelleys.org.uk
> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: OpenPGP digital signature
URL: <http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/attachments/20170430/273341e7/attachment.sig>

More information about the Dnsmasq-discuss mailing list