[CentOS] Some problems with Unbound under CentOS8

Carlos Lopez
2020-03-30T07:47:27Z

Good morning,

I have detected two strange problems with unbound under CentOS8 (fully patched).
I have tried same configuration in an OpenBSD host, and these problems do not
appear.

a/ Error mesage ?connection refused?. I am using this unbound server to resolv
DNS records for our internal domain (Bind9 is configured to listen in localhost
interface, port 5353 udp and in the same host where unbound runs). When I try to
run a nslookup query like this:

> set q=any
> my.internal.dom
;; Connection to 127.0.0.1#53(127.0.0.1) for my.internal.dom  failed: connection
refused.
>
And I don?t understand why. Bind9 resolves this without problems, but unbound
returns connection refused. Unbound is configured to listen in 0.0.0.0 and allow
all connections (access-control: 0.0.0.0/0 allow). The strange thing is that it
only happens with that kind of request, any other request works fine.

b/ Unbound tries to connect to Root DNS servers directly. Every time unbound
starts, it tries to connect to root DNS servers directly and not through
internal DNS. I am using a second unbound server as a cache nameserver in a DMZ
zone and unbound anchor timer service is disabled. My forward config is:

forward-zone:
                name: "."
                forward-addr: 172.22.54.6 at 53<mailto:172.22.54.6 at 53>

Any idea why these problems occur?

--
Regards,
C. L. Martinez