sinkhole

README

sinkhole

Name

sinkhole - blocks domains by using block lists.

Note: Based on MiekG Proof-of-Concept block plugin.

To-Do

• Convert to Go Modules
• Add whitelist feature
• Add regex for filtering (both black and white listing)
• Add possibility to retrieve lists from file
• Docker of CoreDNS plus Sinkhole
• Documentation on compiling CoreDNS and Sinkhole plugin
• Probably more (see DeugNietS)

Description

The sinkhole plugin will block any domain that is on the block lists. The block lists are downloaded on startup or otherwise once a week.

For a domain that is blocked we will return a NXDOMAIN (or pre-defined) response.

THIS IS A WORK-IN-PROGRESS. IT IS NOT PRODUCTION QUALITY!

Syntax

sinkhole

Metrics

If monitoring is enabled (via the prometheus directive) the following metric is exported:

• coredns_block_count_total{server} - counter of total number of blocked domains.

The server label indicates which server handled the request, see the metrics plugin for details.

Examples

Block all domain on the block list(s).

. {
  forward . 9.9.9.9
  sinkhole
}

On startup the block lists are downloaded, and assuming 005.example.org is on the list, it will be blocked, including any subdomains.

2018/09/30 08:40:09 [INFO] plugin/sinkhole: Block lists updated: 226126 domains added
2018/09/30 08:40:12 [INFO] plugin/sinkhole: Sinkholed 005.example.org.
2018/09/30 08:41:41 [INFO] plugin/sinkhole: Sinkholed www.005.example.org.

Known limitations

sinkhole currently requires a working resolver to fetch the downloads. This should be re-worked to use the proxy/forwarder (if defined).

Documentation

Overview

Package example is a CoreDNS plugin that prints "example" to stdout on every packet received.

It serves as an example CoreDNS plugin with numerous code comments.

Index

• type Block
  • func New() *Block
  • func (b *Block) Name() string
  • func (b *Block) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error)

Types

type Block

type Block struct {
	sync.RWMutex

	Next plugin.Handler
	// contains filtered or unexported fields
}

Block is the sinkhole plugin.

func New

func New() *Block

func (*Block) Name

func (b *Block) Name() string

Name implements the Handler interface.

func (*Block) ServeDNS

func (b *Block) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error)

ServeDNS implements the plugin.Handler interface.