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.
config
Specifies an alternative configuration file.
To create a custom config you can:
- pipe --list-defaults to a new file:
ddig --list-defaults > custom.json
- Edit
custom.json
- 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
Unique IP Address Identifier
The first occurrence of each unique IP address is marked by a bullet point:
Unicode Support
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 *)
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 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"
Changelog
[1.3.0] - February 14th 2020
Changed
- Updated default DNS resolvers list.
- Updated dependencies.
Fixed
- Better handling of
nxdomain
. Non-existent domains aren't DNS errors, just an empty answer - so now handling those more sensibly.
[1.2.2] - November 27th 2019
Changed
- Fixed
npm-shrinkwrap.json
problem that prevented npm update
succeeding.
[1.2.0] - November 27th 2019
Changed
- Switched to using
chalk
instead of colors
. - Updated dependencies.
--list-defaults
now pretty-prints the raw json output.
[1.1.4] - November 20th 2019
Changed
- Use * instead of unicode character • to signify unique IP address when
process.stdout.isTTY
is false
1. - Updated Dependencies.
- Shrink-wrapped
npm
dependencies.
[1.1.3] - November 13th 2019
Changed
- Added
--verbose
support tp --help
to display more information. - Dabbled with using
chalk
instead of colors
(on --help
output). - Updated dependency
yargs
to version 14.2.0 - Fixed a cross-platform file path separator bug.
[1.1.2] - September 25th 2019
Changed
- Removed unneeded dependency
valid-filename
. - Updated dependency
colors
to version 1.4.0 - Improved reporting on configuration file location when directory is
.
. - Improved
debug
logging. - Improved reporting on an empty answer (i.e. no error, but no IP address returned).
[1.1.1] - September 21st 2019
Changed
- Fixed a problem when specifying a full path with the
--config
option. - Fixed erroneous warnings when using
--config
.
[1.1.0] - September 20th 2019
Added
- New
--config
option to specify an alternative configuration file. - New
--list-defaults
option which prints a default config json file to the console; useful as an initial custom configuration file.
Changed
- Improved input validation for
--timeout
& --protocol
. - Improved the
Warning
logic for ignored domains to remove erroneous warnings with valid switches and options.
[1.0.4] - September 17th 2019
- Fixed file system path separator problem when attempting to locate a config file on Linux systems.
[1.0.0] - September 17th 2019
FAQ
Question: What terminal/console are you using in the screen shots?
Answer: A pre-release of Microsoft's new tabbed Windows Terminal which has many excellent features, and the ability to configure a background image.