67

I do not want network manager to add DNS servers received from DHCP to my /etc/resolv.conf.

When configuring from GUI/Connections/IPV4 and choose the method Automatic (address only) it still adds DNS servers received via DHCP.

Is it possible to do it per connection (specific ssid ?)

Pabi
  • 7,429
user2913139
  • 811

4 Answers4

82

One way to stop Network Manager from adding dns-servers to /etc/resolv.conf file is to do this:

First open the nm conf file /etc/NetworkManager/NetworkManager.conf:

sudo vim /etc/NetworkManager/NetworkManager.conf

And add this to the [main] section:

dns=none
rc-manager=unmanaged

Save and exit.

Tubrag
  • 3
krt
  • 2,046
7

/etc/resolv.conf is symlinked to /run/resolvconf/resolv.conf. NetworkManager doesn't update /etc/resolv.conf directly (only updates /run/resolvconf/resolv.conf). So:

  • remove symlink (rm /etc/resolv.conf)
  • write you own version of /etc/resolv.conf
Taha Jahangir
  • 296
5

My personal favorite is to use line supersede domain-name-servers in /etc/dhcp/dhclient.conf. No matter what dns access point provides , your ubuntu will always use those dns specified in dhclient.conf

Sample from my file

#send host-name "andare.fugue.com";
send host-name = gethostname();
#send dhcp-client-identifier 1:0:a0:24:ab:fb:9c;
#send dhcp-lease-time 3600;
#supersede domain-name "fugue.com home.vix.com";
supersede domain-name-servers 208.67.220.220;
#prepend domain-name-servers 127.0.0.1;
request subnet-mask, broadcast-address, time-offset, routers,
    domain-name, domain-name-servers, domain-search, host-name,
    dhcp6.name-servers, dhcp6.domain-search,
    netbios-name-servers, netbios-scope, interface-mtu,
    rfc3442-classless-static-routes, ntp-servers,
    dhcp6.fqdn, dhcp6.sntp-servers;
#require subnet-mask, domain-name-servers;
Sergiy Kolodyazhnyy
  • 107,582
2

Just in case I have done a little script to do that automatically (here with google DNS) for every ethernet/wireless connections:

nmcli -g name,type connection  show  --active | awk -F: '/ethernet|wireless/ { print $1 }' | while read connection
do
  nmcli con mod "$connection" ipv6.ignore-auto-dns yes
  nmcli con mod "$connection" ipv4.ignore-auto-dns yes
  nmcli con mod "$connection" ipv4.dns "8.8.8.8 8.8.4.4"
  nmcli con down "$connection" && nmcli con up "$connection"
done
张馆长
  • 131