# 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](https://golang.org) + [Git](https://git-scm.com)  
Installing for windows - linux - freebsd and macos. (linux is recommended)  
Clone the code form Github or [Snix](https://slc.snix.ir) 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](https://openwrt.org): (Mipsbe CPU)
```
# cd nanodns
# GOOS=linux GOARCH=mips GOMIPS=softfloat go build
# scp nanodns root@192.168.1.1:/root/
```
After all connect to your device and run the nanodns binary.  
Building for [Raspberry pi](https://www.raspberrypi.org/): (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](https://regex101.com/)  
```
^([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](https://golang.org):  
Please note that if your regex string contain escape character `'\'` char, put another backslash befor it.  
Read more about [Escape Character](https://yourbasic.org/golang/regexp-cheat-sheet/).
 ```
 ^\babc\b.*$      ---> wrong
 ^\\babc\\b.*$    ---> it's ok
```   

### Support and Social Media
So if you interested to learn [Golang](https://golang.org) follow my [Instagram Account](https://instagram.com/Gonoobies), Thanks.