ciderwebmail software package provides IMAP webmail service, 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 ciderwebmail
ciderwebmail is installed in your system.
Make ensure the ciderwebmail package were installed using the commands given below,
$ sudo dpkg-query -l | grep ciderwebmail *
You will get with ciderwebmail package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Web Software |
| Package | ciderwebmail |
| Version | 1.05+20150729-2 |
| Description | IMAP webmail service |
| Sub Section | Web |