Re: Editing the DNS with Network Manager Non Root

[David Christensen <dpchrist@holgerdanske.com>]

On 5/12/22 07:17, Richmond wrote:
> David Christensen <dpchrist@holgerdanske.com> writes:
>
> > On 5/11/22 06:55, Richmond wrote:
> > > I have a network manager applet on my xfce4 desktop. I am logged in as a
> > > non root user, and I can select edit connections and change the IPv4
> > > settings to DHCP address only and then put in a DNS, then save. If I
> > > look at /etc/resolv.conf though nothing has changed. Restarting
> > > networking or rebooting makes no difference. Perhaps this menu option
> > > should only appear for root, or should cause an error message for non
> > > root users?
> >
> >
> > I typically need to enter the root password whenever I make changes
> > via the Xfce NetworkManager Applet.
> >
> >
> > Please run and post:
> >
> > $ cat /etc/debian_version ; uname -a
> >
> > $ ls -l /etc/resolv.conf
> >
> > $ cat /etc/resolv.conf
> >
> >
> > David
> 11.3
> Linux marvin 5.16.0-0.bpo.3-amd64 #1 SMP PREEMPT Debian
> 5.16.11-1~bpo11+1 (2022-03-02) x86_64 GNU/Linux
>
> -rw-r--r-- 1 root root 79 May 12 15:15 /etc/resolv.conf
>
> # Generated by NetworkManager
> nameserver 192.168.1.1
> nameserver fe80::1%enp2s0
>
> That address 192.168.1.1 is not what I usually have, I was
> experimenting, trying to find out if my router is vulnerable to the DNS
> spoofing reported recently.


The date and time on resolve.conf show that it is current.


"nameserver 192.168.1.1" looks plausible.


I am using a Debian 11 desktop with Xfce:

2022-05-12 15:58:09 dpchrist@laalaa ~
$ echo "'$PS1'"
'\n\D{%Y-%m-%d %H:%M:%S} \u@\h \w\n\$ '

2022-05-12 15:58:19 dpchrist@laalaa ~
$ cat /etc/debian_version ; uname -a
11.3
Linux laalaa 5.10.0-14-amd64 #1 SMP Debian 5.10.113-1 (2022-04-29) 
x86_64 GNU/Linux

2022-05-12 15:58:27 dpchrist@laalaa ~
$ ls -l /etc/resolv.conf
-rw-r--r-- 1 root root 83 May 12 11:06 /etc/resolv.conf

2022-05-12 15:58:33 dpchrist@laalaa ~
$ cat /etc/resolv.conf
# Generated by NetworkManager
search tracy.holgerdanske.com
nameserver 192.168.5.1


If I right-click the Xfce NetworkManager Applet and choose Edit 
Connections, I get a window "Network Connections":

    Ethernet
       Wired connection 1

If I double-click "Wired connection 1", I get a windows "Editing Wired 
connection 1".  If I select the tab IPv4 Settings, there is a drop-down 
list labeled "Methods".

- It is currently set to "Automatic (DHCP)".  The remaining settings are:

    Additional static addresses -> empty

    Additional DNS servers -> empty

    Additional Search domains -> empty

    DHCP client ID -> empty

    Require IPv4 addressing for this connection to complete -> unchecked


If I choose "Automatic (DHCP) addresses only", the labels for the second 
and third settings change.  Putting in some test data:

    Additional static addresses -> Add:
	Address -> 192.168.123.45
	Netmask -> 255.255.255.0
	Gateway -> 192.168.5.1

    DNS servers -> 192.168.123.45,192.168.123.67

    Search domains -> frunobulax.org

    DHCP client ID -> empty

    Require IPv4 addressing for this connection to complete -> unchecked


I then click "Save".


I then enter the root password in the pop-up that opens.


I then close the "Network Connections" window and reboot.

2022-05-12 16:10:25 dpchrist@laalaa ~
$ ls -l /etc/resolv.conf
-rw-r--r-- 1 root root 104 May 12 16:09 /etc/resolv.conf

2022-05-12 16:10:34 dpchrist@laalaa ~
$ cat /etc/resolv.conf
# Generated by NetworkManager
search frunobulax.org
nameserver 192.168.123.45
nameserver 192.168.123.67


Is this the results you expect?


David