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

[Geert Stappers]

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.


Groeten
Geert Stappers
-- 
Silence is hard to parse