We're doing business with let's say,
a.com, which is traceable through root servers.
The company behind
a.com, also provides a private DNS server, which is available only through a VPN, which is needed to resolve services, hosted on sub-domains.
We created a forwarding for one of those subdomains/services
sub.a.com. This works pretty ok, however, querying for
sub.a.com also makes their private nameserver return
;; AUTHORITY SECTION: a.com. 31672 IN NS dns002.dmz.local. a.com. 31672 IN NS dns001.dmz.local.
However, this is wrong, but BIND now caches the NS records for
a.com through their private nameserver. Subsequent queries for
a.com now fail, as their private nameserver is now authoritative, but says that a A record does not exist.
I understand the problem is on the side of
a.com. However, they're unwilling to fix their setup. Can I tell BIND to only forward and allow cache updates for the domain I'm forwarding for, in this case