dyndns-client software package provides virtual package provided by ddclient, inadyn, ez-ipupdate, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install dyndns-client
dyndns-client is installed in your system.
Make ensure the dyndns-client package were installed using the commands given below,
$ sudo dpkg-query -l | grep dyndns-client*
You will get with dyndns-client package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Virtual packages |
| Package | dyndns-client |
| Version | |
| Description | virtual package provided by ddclient, inadyn, ez-ipupdate |
| Sub Section | Virtual |