[Dnsmasq-discuss] DNS forwarding steered based on source interface?

[Geert Stappers]

On Fri, Apr 19, 2024 at 06:20:03AM +0200, Geert Stappers wrote:
> On Thu, Apr 18, 2024 at 10:07:04PM -0400, Christopher Hill wrote:
> > Hi,
> > 
> > I have a question regarding if upstream DNS forwarding can be based on the
> > source interface? Reading the manual I don't believe it is possible..?
> > 
> > The scenario I have is two VLANs that can talk to each other and both use
> > dnsmasqfor local name resolution - this works fine. Each VLAN is configured
> > at the gateway to default route traffic to different VPNs, e.g. VLAN1 out to
> > VPN1, and VLAN2 to VPN2 respectively, and I would like dnsmasq to forward
> > requests originating on VLAN1 to the DNS on VPN1, and the same for VLAN2
> > forwarding to VPN2.
> > 
> > To illustrate:
> > 
> >              tun1     VPN1   VPN2     tun2
> >              10.0.1.1  |       | 10.0.2.1
> >                        +---+---+
> >                            |
> >                           WAN
> >                            |
> >                    +-------+--------+
> >                    |      eth0      |
> >           VLAN 1 <-+-eth1      eth2-+-> VLAN 2
> >   192.168.1.0/24   |    (gateway)   |   192.168.2.0/24
> >                    +----------------+
> > 
> > 
> > I would like to do something like the following in the dnsmasq configuration
> > on the gateway:
> > 
> >   server=eth1,10.0.1.1 at tun1
> >   server=eth2,10.0.2.1 at tun2
> > 
> > i.e. queries arriving on eth1 get sent to 10.0.1.1 via tun1, and queries
> > arriving on eth2 get sent to 10.0.2.1 via tun 2.
> > 
> > I have considered running two instances (one bound to eth1 and another
> > to eth2) but that duplicates setup and makes local queries across VLANs more
> > complicated.
> 
> Read the dnsmasq manual and reread the dnsmasq manual.

 
 --server=[/[<domain>]/[domain/]][<server>[#<port>]][@<interface>][@<source-ip>[#<port>]]



Groeten
Geert Stappers
-- 
Silence is hard to parse