dk-filter software package provides DomainKeys for Sendmail, you can install in your Ubuntu 14.04 LTS (Trusty Tahr) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install dk-filter
dk-filter is installed in your system.
Make ensure the dk-filter package were installed using the commands given below,
$ sudo dpkg-query -l | grep dk-filter *
You will get with dk-filter package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | |
| Package | dk-filter |
| Version | 1.0.0.dfsg-1.2 |
| Description | DomainKeys for Sendmail |
| Sub Section |