NethServer 6

From man dnsmasq: -S, --local, --server=[/[<domain>]/[domain/]][<ipaddr>[#<port>][@<source-ip>|<interface>[#<port>]]

              Specify IP address of upstream servers directly. Setting this flag does not suppress reading of  /etc/resolv.conf,
              use  -R to do that. If one or more optional domains are given, that server is used only for those domains and they
              are queried only using the specified server. This is intended for private nameservers: if you have a nameserver on
              your  network  which  deals  with names of the form xxx.internal.thekelleys.org.uk at 192.168.1.1 then giving  the
              flag -S /internal.thekelleys.org.uk/192.168.1.1 will send all queries for internal machines  to  that  nameserver,
              everything  else  will  go  to  the servers in /etc/resolv.conf. An empty domain specification, // has the special
              meaning of "unqualified names only" ie names without any dots in them. A non-standard port  may  be  specified  as
              part  of  the  IP  address  using a # character.  More than one -S flag is allowed, with repeated domain or ipaddr
              parts as required.

I'm doing something related to this feature request on my mail server. I'm directing queries for nethesis.it to our internal dns and all other queries to a local resolver.
Also, reverse queries are sent to the internal dns.
Here's the custom template:

server=/nethesis.it/192.168.5.253
server=/5.168.192.in-addr.arpa/192.168.5.253
server=127.0.0.1#10053

I think we could build the reverse for class a/b/c networks automatically if the dns ip is in the same network of nethserver.