Hello, I am attempting to set up an internal DNS server that is authoritative for internal resources, but also will respond for external resources on the same domain that it does not have records for.
For example, I have a domain sub.example.com <http://sub.example.com/>, and I want to have internal entries in the BIND zone file for host1.sub.example.com <http://host1.sub.example.com/> and host2.sub.example.com <http://host2.sub.example.com/>. That part is working fine. However, there is a publicly available DNS entry for sub.example.com <http://sub.example.com/> that I want my internal clients to be able to resolve, but I don’t want to have the IP in the BIND zone file, because the IP is dynamic. There are also some hosts (host3.sub.example.com <http://host3.sub.example.com/>) and (host4.sub.example.com <http://host4.sub.example.com/>) that are externally resolvable that I don’t want to put in my internal BIND file because they are not controlled by me. (Think CNAME to a SaaS application) I’ve attempted to do this as follows, and it seems to make sense that it would work, but it does not. named.conf: zone “sub.example.com" IN { type master; file "/etc/bind/sub.example.com.zone"; forward first; forwarders { 1.1.1.1; 1.0.0.1; }; }; sub.example.com <http://sub.example.com/>.zone: $ORIGIN sub.example.com. $ttl 600 @ 300 SOA dns.sub.example.com. ( taylor.viertaxa.com. ; address of responsible party 2020090101 ; serial number 300 ; refresh period 300 ; retry period 604800 ; expire time 300 ) ; minimum ttl 300 NS elinore.ns.cloudflare.com. 300 NS hal.ns.cloudflare.com. host1 60 A 10.x.x.x host2 60 A 10.x.x.x What I would expect to happen, is that BIND sees “forward first” and attempts to look up the hostname host3.sub.example.com <http://host3.sub.example.com/> on the listed forwarders, and succeeds (there’s an entry publicly available for that one. What actually happens, is if I query for sub.example.com <http://sub.example.com/> I get the following from nslookup: *** Can't find sub.example.com: No answer And if I query for host3.example.com <http://host3.example.com/>, I get the following from nslookup: ** server can't find host3.sub.example.com: NXDOMAIN BIND version: Package: bind9 Version: 1:9.11.5.P4+dfsg-5.1+deb10u2 Thank you in advance for any help you might be able to provide.
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