7

I have CentOS 7.2 (guest in VirtualBox, vagrant box centos/7, no GUI).

I see there is a nameserver in file:

$ cat /etc/resolv.conf
# Generated by NetworkManager
nameserver 10.0.2.3

But how to add or replace with new one?

I have done this manually directly in the network:

$ vi /etc/sysconfig/network-scripts/ifcfg-eth0
PEERDNS=no
DNS1=91.217.197.2
DNS2=8.8.8.8

And it works.

But is there any way to do this through nmcli?

P.S. No nmtui installed (in a selected system).

15

Useful nmcli manual

here is the syntax to modify an existing connection.

nmcli con mod <connectionName> ipv4.dns "8.8.8.8 8.8.4.4"

connectionName can be found by command: nmcli con.
In the question case, it will be "System eth0"

you should not really edit /etc/resolv.conf manually as it is generated by NetworkManager service.

  • Yeah, thx, found it already. A bit edited your answer... But how to replace exist nameserver? – Kirby Oct 22 '16 at 11:02
  • there is "+ipv4.dns" and "ipv4.dns" can be used, but second one (without "+") doesn't replace. – Kirby Oct 22 '16 at 11:04
  • 2
    I'd rather use nmtui or if possible the GUI version as well. There is no need to be a command line ninja, if you have a more convenient option which is doing the same thing. – lauc.exon.nod Oct 22 '16 at 13:08
  • 2
    @lauc.exon.nod Some options aren't available in nmtui, and you have to use nmcli to get at them. – Michael Hampton Oct 26 '16 at 1:27
  • Link is dead.... – ceving Jan 14 at 16:52
7

there is good TUI tool developed by red hat named nmtui that you really should try. it is pre-installed on various distros, nowadays, but if it is not on yours, try:

  sudo yum install networkmanager-tui

it uses a curses based text interface - accessible from the command line. nmcli is only especially necessary when writing scripts, and has larger room for error due to the larger variety of possible input.

  • I cannot use it until set up new dns, because there is no Internet connection. Anyway, thanks for this point. – Kirby Oct 22 '16 at 11:31
  • it is included in various distros, nowadays – infinite-etcetera Dec 7 '16 at 15:45
  • Possibly so. I just didn't have it my docker container. – Kirby Mar 19 '18 at 12:45
2

In addition to setting the ipv4.dns property described above...

To exclude the DHCP provided DNS servers...set the ipv4.ignore-auto-dns property to yes.

nmcli con mod <connectionName> ipv4.ignore-auto-dns yes

To enable the changes, bring the connection down then up:

nmcli con down <connectionName>
nmcli con up <connectionName>

Verify with cat /etc/resolv.conf

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