Chapter 15. KMail — The KDE Mail Application

Table of Contents

Mail Formats
Access Types
Configuring KMail
Defining Your User Identity
Setting up Network Connections
Configuring the Appearance of KMail
Using KMail
Creating a New Message
Message Folders
The Address Book
Filter Rules
Examples of Filters
Mail Encryption with PGP or GnuPG
Signing Messages
Checking the Signature of a Received Message
Sending Public Keys
Decoding Encrypted Messages
Encrypting Your Own Messages
For More Information


KMail is the KDE mail application. In addition to sending and receiving e-mail and using multiple mail protocols, it offers the possibility to configure several user-defined filters for sorting e-mail messages in individual folders. The encryption, decryption, and signing of e-mail messages can also be handled conveniently in KMail.

Mail Formats

KMail can save messages in the following formats:


This traditional UNIX format (the oldest) saves all messages in a single file. Directories are also simulated by means of individual files. The individual mails can only be distinguished by the From line.


In contrast to the mbox format, the MailDir format has a unique file name for every message. The messages are stored in the respective directories and can easily be identified and further processed. KMail uses the MailDir format (as the more convenient alternative) by default, but MailDir is not supported by many other e-mail programs. This can be a disadvantage if you want to switch to a different e-mail programm later and still access your old e-mails. Processing old mails in mbox format is no problem, however, if you select MailDir. Just copy or move the files to the MailDir folder.