distributed-dig

Quick Start

Installation

Install globally:

npm install -g distributed-dig

Usage

Lookup a single domain:

ddig domain

Overview

A utility which makes DNS lookup requests across multiple DNS resolvers and collates the results.

Useful for checking if a DNS record has been fully propagated, or for querying the origins behind an AWS Route 53 / Azure Traffic Manager record (or any other DNS-based load balancing solution).

Installation

Installing globally is recommended:

npm install -g distributed-dig

Usage

ddig domain [domain [domain] ...] [options]

Options

The following options are available:

--port <number>                  Specify the DNS port [53]
--protocol <upd|tcp>             Specify the DNS protocol [udp]
--timeout <number>               Specify the DNS timeout in milliseconds [2500]
--edns <true|false>              Enable or disable EDNS(0) [false]
--config <filename>              Specify an alternative configuration file
--list-resolvers                 List resolvers configured in config file
--list-options                   List DNS request options configured in config file
--list-defaults                  Print json of default config file settings
--verbose                        Outputs more information
--no-color                       Switches off colour output
--version                        Display version number
--help                           Display this help

port

Specify the TCP/UDP port tro use when connecting to the DNS resolver. Default: 53

protocol

Specify whether to use UDP or TCP when connecting to the DNS resolver. Default: udp

timeout

Specifies the timeout in milliseconds to wait for a response from each DNS resolver. Default: 2500 (2.5 seconds)

edns

Enables EDNS(0) Default: false (disabled)

With EDNS(0) enabled, if an upstream resolver doesn't support it then the standard DNS will be used as a fallback. Even though EDNS is support by ~90% of resolvers on the internet [^1], it is disabled by default in ddig as it may cause the resolver to return the IP address it considers closest to you, which is counter-productive to the purpose of querying many geographically distributed DNS resolvers.

[^1]: Internet Systems Consortium - Partial EDNS Compliance Hampers Deployment of New DNS Features

config

Specifies an alternative configuration file.

To create a custom config you can:

1. pipe --list-defaults to a new file: ddig --list-defaults > custom.json
2. Edit custom.json
3. Use the new configuration file: ddig --config [path]custom.json example.com

list-resolvers

Lists the resolvers configured in the distributed-dig.json config file:

list-options

Lists the options configured in the distributed-dig.json config file:

list-defaults

Prints out a sample default config file in raw json. Pipe it to a file for an initial customised configuration file.

verbose

Switches on verbose mode which outputs the following additional fields:

• Full recursive answer (i.e. nested cname records)
• Resolver IP Address
• Response time

--verbose also modifies the --list-resolvers and --list-options switches.

no-color

If your terminal has problems rendering the colour output then you can switch it off by using --no-color.

version

Prints out distributed-dig's version number.

help

Displays the help screen:

Examples

Lookup a single domain

• List the IP address returned for www.asos.com from each of the configured resolver:

ddig www.asos.com

Lookup a single domain with verbose enabled

• List the IP address and full recursive path returned for www.asos.com from each of the configured resolver:

ddig www.asos.com --verbose

Lookup multiple domains with an increased timeout

• List the IP addresses returned for both www.asos.com & secure.asos.com from each of the configured resolver with a 5 second timeout:

ddig www.asos.com my.asos.com secure.asos.com --timeout 5000

Features

Lookup a domain from a URL

As of version 1.8.0 you can provide a URL and the domain will be extracted. This is handy when performing a copy/paste from a browser's address bar.

ddig https://example.com

Unique IP Address Identifier

The first occurrence of each unique IP address is marked by a bullet point:

Unicode Support detection for Unique Address Identifier character

The bullet point character used is U+2022 • BULLET (HTML •). If it is detected that the output is being piped (to a file or to more | cat) then the ascii character 42 * Asterisk (HTML *)

Filtering out just unique addresses

As of version 1.7.0 there is an option to provide a --unique switch which lists only the first occurrence of each distinct IP address returned. N.B. It will not filter out errors

Column Width Warning

If you use the --verbose switch and have a terminal window that's narrower than 130 columns you'll see a warning:

Configuration File

All Options and Resolvers are configured in distributed-dig.json file. This file can exist in any of the following locations:

• The current working directory - node -p process.cwd()
• The home directory - node -p require('os').homedir()
• The application's root directory (i.e. the same directory as distributed-dig.js)

Request Options

The default options are:

"options": {
    "request": {
      "port": 53,
      "type": "udp",
      "timeout": 2500,
      "try_edns": false,
      "cache": false
    },
    "question": {
      "type": "A"
    }
}

DNS Resolvers

Resolvers are configured in an array with each resolver having a nameServer element which should be the IPv4 or IPv6 address, and a provider element which is just a free-form text label:

"resolvers": [
    {
      "nameServer": "208.67.222.222",
      "provider": "OpenDNS (Primary)"
    },
    {
      "nameServer": "208.67.220.220",
      "provider": "OpenDNS (Secondary)"
    },
    {
      "nameServer": "217.199.173.113",
      "provider": "United Kingdom"
    }
]

You can find a list of public DNS servers here and here, and tailor the configured list for your own requirements.

Debugging

distributed-dig uses the npm package debug. If you set the environment variable debug to ddig you'll see full debug output.

Windows

set debug=ddig

Linux

DEBUG=ddig

Powershell

$env:debug="ddig"

FAQ

• Where is the Change Log?
• What terminal/console are you using in the screen shots?

Where is the Change Log

The CHANGELOG.md can be found here

What terminal are you using

I'm using Microsoft's new tabbed Windows Terminal which has many excellent features, and the ability to configure a background image.