https://github.com/daschr/dnswatch

watch for changes of A/AAAA records
https://github.com/daschr/dnswatch

command-line dns shell shell-scripting

Last synced: 8 days ago
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watch for changes of A/AAAA records

• Host: GitHub
• URL: https://github.com/daschr/dnswatch
• Owner: daschr
• License: mit
• Created: 2020-06-25T06:17:04.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2020-08-25T06:56:45.000Z (over 4 years ago)
• Last Synced: 2023-08-24T09:24:05.158Z (over 1 year ago)
• Topics: command-line, dns, shell, shell-scripting
• Language: C
• Homepage:
• Size: 32.2 KB
• Stars: 6
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# dnswatch

Wait for changes of DNS A/AAAA records and run a given command each time.

## install

* `make`

* `sudo make install`

## usage

`dnswatch [@|T|AAAA] [--] [fqdn] [command] [args]...`

 The changed records are stored in the envvars `$ADDRESSES` and `$ADDRESS`.

## "But for what is it good for?!?"

Well, I use it for wireguard clients connecting to a peer with a dynamic address.

`dnswatch T30 nonexistent.freemyip.com sh -c 'wg-quick down wg0; wg-quick up wg0'`

or

`dnswatch @208.67.222.222 T120 AAAA nonexistent.freemyip.com restart_wireguard.sh`

## more examples

* `dnswatch golem.de sh -c 'echo "changed to $ADDRESSES!"'` <-- will contact the default name server (1.1.1.1) every 60 seconds, executes the command in case of change

* `dnswatch @8.8.8.8 golem.de sh -c 'echo "changed to $ADDRESSES!"'` <-- will contact google's name server every 60 seconds, executes the command in case of change

* `dnswatch @8.8.8.8 T10 golem.de sh -c 'echo "changed to $ADDRESSES!"'` <-- will contact google's name server every 10 seconds, executes the command in case of change

* `dnswatch @8.8.8.8 T10 AAAA golem.de sh -c 'echo "changed to $ADDRESSES!"'` <-- will contact google's name server every 10 seconds, fetches the AAAA record, executes the command in case of change