CoreDNS installer script for AsusWRT Merlin routers with config examples

00_CoreDNS_installer_script_for_AsusWRT_Merlin.md

CoreDNS installer script for AsusWRT Merlin

Installation

curl -sL https://gist.githubusercontent.com/vi7/e41b07ff7d0fb845ac281cd940876e2a/raw/coredns_installer_asuswrt_merlin.sh | sh && rm -f coredns_installer_asuswrt_merlin.sh

Running CoreDNS

Prepare Corefile and zone files (if needed) using examples from this gist, create launcher script /jffs/addons/coredns/coredns.sh with the following contents:

#!/usr/bin/env sh

nohup /jffs/addons/coredns/coredns --conf /jffs/etc/coredns/Corefile | logger -s -c -t coredns

Add following lines to the services start script /jffs/scripts/services-start:

logger -c -t services-start "Starting CoreDNS"
/jffs/addons/coredns/coredns.sh &

Disable builtin DNS server by creating /jffs/configs/dnsmasq.conf.add with port=0 inside (this does not disable DHCP)

Reboot router

coredns_installer_asuswrt_merlin.sh

#!/usr/bin/env sh

#############
### USAGE ###
#############

# 1. Modify version, arch and install path vars below if needed
# 
# 2. SSH to the router, `cd /jffs` and run:
#
# curl -sL https://gist.githubusercontent.com/vi7/e41b07ff7d0fb845ac281cd940876e2a/raw/coredns_installer_asuswrt_merlin.sh | sh && rm -f coredns_installer_asuswrt_merlin.sh



VERSION="1.9.1"
ARCH="linux_arm64"
INSTALL_PATH="/jffs/addons/coredns"


mkdir -p "$INSTALL_PATH"
cd "$INSTALL_PATH"
if [ ! -f coredns ]
then
  curl -LO "https://github.com/coredns/coredns/releases/download/v${VERSION}/coredns_${VERSION}_${ARCH}.tgz"
  tar xzvf "coredns_${VERSION}_${ARCH}.tgz"
  chmod a+x coredns
  rm -vf "coredns_${VERSION}_${ARCH}.tgz"
  echo "CoreDNS is installed to the $INSTALL_PATH"
else
  echo "SKIPPING! CoreDNS seems to be present in the $INSTALL_PATH"
fi

Corefile

#
# This Corefile example assumes:
# - port 53 is free on the router
# - zone files are created under '/jffs/etc/coredns/zones' (See examples in this gist)
#
# Create '/jffs/configs/dnsmasq.conf.add' with 'port=0'
# to disable builtin dnsmasq DNS server (this does not disable DHCP)
#
.:53 {
  log {
    class denial error
    # uncomment to log everything
    #class all
  }
  errors
  loadbalance
  prometheus 0.0.0.0:9153
  reload
  auto {
    directory /jffs/etc/coredns/zones db\.(.*) {1}
  }
  # 91.239.100.100 - belongs to https://blog.uncensoreddns.org
  forward . tls://91.239.100.100 tls://8.8.8.8 tls://8.8.4.4 tls://1.1.1.1 tls://1.0.0.1
}

db.1.168.192.in-addr.arpa

$ORIGIN 1.168.192.in-addr.arpa.
$TTL 3h

@   IN SOA  router.lan. root.lan. (
            2021112801  ; serial in the format YYYYMMDD##
            24h         ; refresh after 24 hours
            2h          ; retry after 2 hours
            1w          ; expire after 1 week
            1h )        ; minimum TTL of 1 hour
;
;
    IN NS   router.lan.
;
;
1   IN PTR  router.lan.
2   IN PTR  host1.lan.
3   IN PTR  host2.lan.

db.lan

$ORIGIN lan.
$TTL 3h

@   IN SOA  router.lan. root.lan. (
            2022012501  ; serial in the format YYYYMMDD## - !!! CHANGE ON EVERY ZONE UPDATE
            24h         ; refresh after 24 hours
            2h          ; retry after 2 hours
            1w          ; expire after 1 week
            1h )        ; minimum TTL of 1 hour
;
;
    IN NS   router.lan.
;
;
router            IN A  192.168.1.1
host1             IN A  192.168.1.2
host2             IN A  192.168.1.3
;
; Aliases
;
service-x       IN CNAME  host1.lan.