[Dnsmasq-discuss] ignore mac address for one of the dhcp

[John Siu]

On Mon, Apr 13, 2020 at 12:15 PM Geert Stappers <stappers at stappers.nl>
wrote:

> On Mon, Apr 13, 2020 at 10:18:31AM -0400, John Siu wrote:
> > On Mon, Apr 13, 2020 at 4:54 AM Geert Stappers wrote:
> > > On Sun, Apr 12, 2020 at 03:14:33PM -0400, John Siu wrote:
> > > > I am running dnsmasq on a multiple port box. Following are dhcp
> config
> > > > for the lan and dmz ports:
> > > >
> > > > ---
> > > >
> > > > ## LAN
> > > > dhcp-range=tag:lan,::1,constructor:lan,ra-names,72h # IPv6
> > > > dhcp-range=tag:lan,172.16.168.130,172.16.168.250,72h # IPv4
> > > > dhcp-option=tag:lan,option:router,172.16.168.1 # option 3 default gw
> > > > dhcp-option=tag:lan,option:dns-server,172.16.168.1
> > > >
> > > > ## DMZ
> > > > dhcp-range=tag:dmz,::1,constructor:dmz,ra-names,72h # IPv6
> > > > dhcp-range=tag:dmz,10.10.10.100,10.10.10.120,72h # IPv4
> > > > dhcp-option=tag:dmz,option:router,10.10.10.1 # option 3 default gw
> > > > dhcp-option=tag:dmz,option:dns-server,10.10.10.1
> > > >
> > > > ---
> > > >
> > > > They work correctly for network connected to those ports.
> > >
> > > I wonder how.
> > >
> > > I mean: The provided information looks incomplete to me.
> > > Might be due an attempt to make the config more generic.
> > >
> > >
> > >
> > Following is the complete 92-dhcp.conf file I am using. It is not
> generic.
> > I have interface name "lan" and "dmz" setup in network config.
>
> Ah
>
> > ---
> > log-dhcp
> > quiet-dhcp
> > quiet-dhcp6
> > quiet-ra
> >
> > enable-ra
> >
> > ## LAN
> > dhcp-range=tag:lan,::1,constructor:lan,ra-names,72h # IPv6
> > dhcp-range=tag:lan,172.16.168.130,172.16.168.250,72h # IPv4
> > dhcp-option=tag:lan,option:router,172.16.168.1 # option 3 default gw
> > dhcp-option=tag:lan,option:dns-server,172.16.168.1 # option 6 dns
> > #dhcp-option=tag:lan,option:ntp-server,172.16.168.1
> >
> > ## DMZ
> > dhcp-range=tag:dmz,::1,constructor:dmz,ra-names,72h # IPv6
> > dhcp-range=tag:dmz,10.10.10.100,10.10.10.120,72h # IPv4
> > dhcp-option=tag:dmz,option:router,10.10.10.1 # option 3 default gw
> > dhcp-option=tag:dmz,option:dns-server,10.10.10.1 # option 6 dns
> > #dhcp-option=tag:dmz,option:ntp-server,10.10.10.1
> >
> > ## Lease
> > dhcp-hostsfile=/etc/dnsmasq.d/extra/dhcp.hosts
> > dhcp-leasefile=/etc/dnsmasq.d/extra/dhcp.lease
> > ---
> >
> > > > However, I am having issue with the switch which connect to both dmz
> > > > and lan ports with different VLANs. As those VLAN ports share the
> same
> > > > mac address, sometimes the switch will pick up IP from the lan side,
> > > > and sometimes from the dmz side.
> > > >
> > > > How can I make dnsmasq only serve IP on the lan side for this
> specific mac
> > > > address?
> > >
> > > Tell more about what you have.
> > >
> > The switch is a Netgear GS908E. It has 8 ports. I setup 2 vlan, one for
> > dmz, one for lan. So there is one cable from my server dmz port to the
> dmz
> > vlan, same for lan.
>
> Thanks.  I'm not used to interface names like 'lan' or 'dmz'.
> I'm used to interface names like 'eth0' and 'enp181s0f2'
>
>
> > The switch is configure to use dhcp for its ip.
>
> OK, Acknowledge.  (As in "I respect your design decission" )
>
>
> > However, it requests dhcp from all ports. As a result, sometime it pick
> up
> > 172.x.x.x, and sometimes it pickup 10.x.x.x address.
>
> (and that is the challenge we are facing)
>
>
> I have been reading the dnsmasq manual page  (again ;-) But I could not
> find a clear solution for coping with duplicate MAC-addresses.
>
> The is `--dhcp-ignore=tag:...` no use in this case.
>
>
> Idea  (wild idea?)
>
>   dhcp-host:01:00:18:4D:C0:3F:0E,172.16.168.251,12h
>
> I tried , also with tag:lan, and set:lan, the switch will still pick up
10.x.x.x address.

>
> In other words: Make a "static reserveration" for the swith in LAN
>
>
>
>
> Regards
> Geert Stappers
> --
> Silence is hard to parse
>
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