imp4 software package provides webmail component for horde framework, you can install in your Ubuntu 12.04 LTS (Precise Pangolin) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install imp4
imp4 is installed in your system.
Make ensure the imp4 package were installed using the commands given below,
$ sudo dpkg-query -l | grep imp4 *
You will get with imp4 package name, version, architecture and description in a table
| Distro | Ubuntu 12 04 lts precise pangolin |
| Section | Web Software |
| Package | imp4 |
| Version | 4.3.7+debian0-2.1 |
| Description | webmail component for horde framework |
| Sub Section | Web |