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DNS Configuration with resolv.conf

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Lucas Holt edited this page Aug 22, 2022 · 1 revision

By default, /etc/resolv.conf is updated when DHCP is enabled for an interface. This is useful for WiFi or laptops where you frequently change networks. However, it can be problematic sometimes when different DNS servers are required.

For static IP addresses, this is not modified automatically.

Preventing Automatic Config Changes

Methods to try:

  • Use a static IP address
  • Make /etc/resolv.conf immutable
  • Override the dhclient configuration
  • Turn off resolvconf

Static IP

Simply edit your /etc/rc.conf and replace DHCP in your ifconfig line with a static IP configuration

Immutable resolv.conf

chflags schg /etc/resolv.conf

Override the dhclient config

place the following in /etc/dhclient.conf, but change the name of the interface as appropriate. This example uses OpenDNS with an Intel Gigabit NIC.

interface "em0" {

`supersede domain-name-servers 208.67.222.222,208.67.220.220;`

}

You will need to restart the dhclient for changes to take effect.

service dhclient restart em0

Disable resolvconf(8)

Create a file

/etc/resolvconf.conf

Place this in the file

resolv_conf="/dev/null"

Alternatively, disable in /etc/rc.conf resolvconf="NO"

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