Nano DNS

Simple and tiny DNS server written in Golang for filtering domains and speed up name resolution functionality.
Core features:
forward and cache dns queries
block domain names with regex.

Installation

Prerequisites: Golang + Git
Installing for windows - linux - freebsd and macos. (linux is recommended)
Clone the code form Github or Snix servers.

# git clone https://slc.snix.ir/snix/nanodns.git      # Snix
# git clone https://github.com/khokooli/nanodns.git   # Github  
# cd nanodns 
# go get -v
# go build
# ./nanodns
2020/07/31 05:11:29 upstream dns: 1.1.1.1:53 connection udp
2020/07/31 05:11:29 dns listen on: 0.0.0.0:53 connection udp
2020/07/31 05:11:29 load banned domains from: noacc.txt

Cross Compiles

If you want to build this for other device architectures (like Mikrotik, Raspberry pi) follow this.
Build for Mikrotik RB 2011 UIAS-IN runing on OpenWRT: (Mipsbe CPU)

# cd nanodns
# GOOS=linux GOARCH=mips GOMIPS=softfloat go build
# scp nanodns [email protected]:/root/

After all connect to your device and run the nanodns binary.
Building for Raspberry pi: (ARM64 CPU's)

cd nanodns
GOARCH=arm64 GOOS=linux go build

Usage and Options

# ./nanodns -h
Usage of ./nanodns:
  -fakeadd string
        an ip to send back for filtered domains <ipaddr> (default "127.0.0.1")
  -filter string
        filtered domains <filename> - regex is supported (default "noacc.txt")
  -loaddr string
        dns server listen address <ipaddr:port> (default "0.0.0.0:53")
  -loconn string
        dns server connection type <udp|tcp> (default "udp")
  -upaddr string
        upsteam dns server to connect <ipaddr:port> (default "1.1.1.1:53")
  -upconn string
        upsteam dns connection type <udp|tcp> (default "udp")

Regex Domain Blocking

You can use regex for blocking domain names, create a file like noacc.txt in nanodns directory.
For blocking all com and example.net put the following in noacc.txt
Regex Test Tool Online

^([a-z0-9]+[.])*com.$
example.net.

Block all domains if contain following words:
advertise, torrent or hack

^(torrent|hack|advertise).*$

Block any domain except google.com and snix.ir

^((?!google[.]com[.]|snix[.]ir[.]).)*$

Notes about regex in Golang:
Please note that if your regex string contain escape character '\' char, put another backslash befor it.
Read more about Escape Character.

^\babc\b.*$      ---> wrong
^\\babc\\b.*$    ---> it's ok

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