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Playing around with CoreDNS

dns, coredns

saving your time: In this post, we will explore how to set up a basic DNS server using CoreDNS and configure it to serve local domain names while forwarding other DNS queries to external resolvers

Summary #

  1. Download the Ubuntu Server ISO: Ubuntu Downloads
  2. Install Ubuntu Server on VirtualBox
  3. Set the virtual machine’s network mode to bridge
  4. Disable systemd-resolved
  5. Download CoreDNS
  6. Create a Corefile with the desired configurations
  7. Create a DNS zone file for CoreDNS
  8. On the host machine, add an entry in /etc/hosts mapping the VM’s IP for DNS resolution
  9. Test name resolution using a browser and dig

ubuntu-vm

After installing the virtual machine (VM) and assigning an IP address via DHCP, follow the steps below (:

Configure Ubuntu Server #

Login using SSH and download CoreDNS

sudo systemctl stop systemd-resolved
wget https://github.com/coredns/coredns/releases/download/v1.10.1/coredns_1.10.1_linux_amd64.tgz
tar -xvzf coredns_1.10.1_linux_amd64.tgz
touch admin.meudominio.local
touch Corefile

Create file Corefile

admin.meudominio.local {
    file ./admin.meudominio.local
    log
    errors
}

.:53 {
    forward . 8.8.8.8 1.1.1.1
    cache
    log
    errors
}

Create file admin.meudominio.local

$ORIGIN admin.meudominio.local.
$TTL 3600

@       IN  SOA  ns.admin.meudominio.local. admin.admin.meudominio.local. (
            2025021901 ; serial
            3600       ; refresh
            1800       ; retry
            1209600    ; expire
            3600 )     ; minimum TTL

@       IN  NS  ns.admin.meudominio.local.

ns      IN  A   192.168.100.218
@       IN  A   192.168.100.1   ; admin.meudominio.local
db      IN  A   192.168.100.1   ; add db.admin.meudominio.local
apolzek IN  CNAME github.com.   ; add CNAME

start CoreDNS

sudo coredns -conf ./Corefile

Configure linux host (i’m using ubuntu) #

Add the VM’s IP to resolv.conf

nameserver 192.168.100.218 # VM with Ubuntu Server and CoreDNS

Testing #

Run in the host terminal

dig @192.168.100.218 apolzek.admin.meudominio.local
dig @192.168.100.218 admin.meudominio.local

ubuntu-vm

gif-dig