resolvd
resolvd(8) was added in OpenBSD 6.9. This daemon manages /etc/resolv.conf by automatically adding nameservers from various sources such as dhcpleased(8), iked(8), slaacd(8), and other network devices.
By default, OpenBSD enables and starts resolvd on bootup.
Default nameservers
The default nameserver used in name lookup is located in resolv.conf:
# cat /etc/resolv.conf lookup file bind family inet6 inet4 nameserver 127.0.0.1
Changing default nameservers
You can remove all nameservers for the interface if0 using
route's nameserver command:
Note: You must replace if0 with your actual interface name.
# route nameserver if0
Nameservers can also be manually set using route:
# route nameserver if0 203.0.113.1 # cat /etc/resolv.conf nameserver 203.0.113.1 # resolvd: if0 lookup file bind family inet6 inet4 nameserver 127.0.0.1
Disabling resolvd
Sometimes, resolvd may give you incorrect nameserver information. This may happen if your DHCP server is providing an incorrect DNS server (or simply a DNS server you don't want to use).
There are two methods to fix this. One is to configure dhclient? to override or ignore the DNS server. The other is to simply disable resolvd(8) and manually edit resolv.conf(5).
Note that resolvd(8) may automatically overwrites resolv.conf(5), and those nameservers may supersede the ones you specify. In that case, you can disable resolvd(8):
# rcctl disable resolvd # rcctl stop resolvd
Now, edits to /etc/resolv.conf will persist.