I’ve got Ubuntu 21.10 installed on a new Framework laptop. I would like it to use my local, custom DNS Server that I set up on a Synology NAS. So, I put that IP address in the correct (I hope) spot in the Ubuntu settings:
However, it appears that this custom DNS server is not being used at all. I run an nslookup command on a local service and it appears to be using some other DNS server, thus it cannot find my local service:
I have heard from some sources that I should edit the /etc/resolv.conf file directly, but other sources say that it’s bad practice to do so and that I should use Ubuntu’s settings.
So what am I doing wrong and what should I do to make Ubuntu respect my choice of DNS server(s)?
Edit 12/17/2021: Per the comments, here is the result of systemd-resolve --status initially (with the "Automatic" toggle turned on):
Global
Protocols: -LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
resolv.conf mode: foreign
Link 2 (wlp170s0)
Current Scopes: DNS
Protocols: +DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
Current DNS Server: 192.168.50.1
DNS Servers: 192.168.50.1 192.168.50.10
And then here is the result after turning the "Automatic" toggle off:
Global
Protocols: -LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
resolv.conf mode: foreign
Link 2 (wlp170s0)
Current Scopes: DNS
Protocols: +DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
Current DNS Server: 192.168.50.10
DNS Servers: 192.168.50.10
So, my router is on 192.168.50.1, but I don’t see any way that it can use 192.168.50.10 for its primary DNS server.
>Solution :
In your system settings screenshot, you currently have "Automatic" enabled next to the field where you enter your custom DNS IP address.
You should disable "Automatic" for DNS. Once you do that, DNS requests should be queried from the IP address you specify in the field.
Keep in mind that individual applications might not use the DNS server that you specify in your system settings. Examples include Tor, VPN clients, and potentially even your web browser. Notably, there has been a trend for apps to move to using DoH since it is more secure and more private than typical DNS lookups which are sent in plaintext.
Getting your DNS server to work for these applications will generally need to be configured for each application in their settings. For example, Firefox has been pushing DoH lately, but you can opt-out.