Hostnames on an internal subnet that also resolve in public DNS

[Tom Harrison]

Hello -- re MaraDNS 1.2.12.08 running on Ubuntu/Debian...

I need intercommunication of a cluster of servers living in a private  
network (10.x.x.x), but also need to get to the address of the hosts  
via public DNS.  So, for example, web1.example.com might resolve to  
10.0.0.1, routable only within the subnet, but from an external  
location (our office) would resolve to a publicly routable IP like  
98.76.544.321.  Within the subnet the servers also need to get at  
public addresses too, like google.com.  I have all of this working  
with the config below.

However, some of the addresses for our domain are not in the subnet,  
e.g. our office "corp.example.com"; these are public addresses that  
can be resolved by the upstream servers.  Is there a way to configure  
MaraDNS so that a "miss" on a name like "corp.example.dom" is passed  
along thus resolving to its public address?

mararc:
ipv4_bind_addresses = "10.252.110.37"
chroot_dir = "/etc/maradns"
hide_disclaimer = "YES"
recursive_acl = "10.0.0.0/8"
upstream_servers = {}
upstream_servers["."] = "172.16.0.23"
csv2 = {}
csv2["example.com."] = "db.example.com"

db.example.com:
master.example.com. 10.252.110.37
web1.example.com. 10.252.46.6