OpenBSD 6.8 comes with default installed Unbound daemon. Using Unbound, you would not longer depends on other DNS provider, keep what domain you access to yourself.
Enable and start unbound
# rcctl enable unbound
# rcctl start unbound
It now listens on port 53, on localhost address - good, sane default:
$ netstat -nl | grep 53
tcp 0 0 127.0.0.1.53 *.* LISTEN
udp 0 0 127.0.0.1.53 *.*
tcp6 0 0 ::1.53 *.* LISTEN
udp6 0 0 ::1.53 *.*
Now check using dig:
$ dig pymi.vn @127.0.0.1
; <<>> dig 9.10.8-P1 <<>> pymi.vn @127.0.0.1
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7832
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;pymi.vn. IN A
;; ANSWER SECTION:
pymi.vn. 231 IN A 104.21.61.168
pymi.vn. 231 IN A 172.67.212.45
;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Sun Feb 28 22:15:35 +07 2021
;; MSG SIZE rcvd: 68
The result is same as returned by 1.1.1.1:
$ dig +short pymi.vn @1.1.1.1
172.67.212.45
104.21.61.168
Config laptop to use the local DNS resolver
Laptop uses wireless network often uses DHCP to config.
Example config:
$ cat /etc/hostname.iwm0
nwid "The Coffee House" wpakey thecoffeehouse
dhcp
It uses DHCP to get IP and DNS config, this in turns, re-write /etc/resolv.conf
$ cat /etc/resolv.conf
# Generated by iwm0 dhclient
nameserver 8.8.8.8
lookup file bind
To override the nameserver, change DHCP client config:
$ cat /etc/dhclient.conf
supersede domain-name-servers 127.0.0.1;
To reconnect wireless network with new DHCP client config, run:
# sh -x /etc/netstart
Now DNS would be resolved using unbound.
Happy OpenBSD using.