Chapter 8. Next Steps and Where to Go From Here There is lots of useful documentation in /usr/share/doc as well. In particular, /usr/share/doc/HOWTO and /usr/share/doc/FAQ contain lots of interesting information. To submit bugs, look at /usr/share/doc/debian/bug $_{*}$. To read about Debian/Ubuntu-specific issues for particular programs, look at /usr/share/doc/(package name)/README.Debian . Help on Ubuntu can be found on the Ubuntu web site (http://www.ubuntu.com/). In particular, see the Ubuntu documentation (http://help.ubuntu.com/) pages for information on a wide variety of topics. The Ubuntu mailing lists (http://lists.ubuntu.com/) and the Ubuntu Forums (http://www.ubuntuforums.org/) can be invaluable sources of help from the Ubuntu community. A general source of information on GNU/Linux is the Linux Documentation Project (http://www.tldp.org/). There you will find the HOWTOs and pointers to other very valuable information on parts of a GNU/Linux system. Today, email is an important part of many people’s life. As there are many options as to how to set it up, and as having it set up correctly is important for some Ubuntu utilities, we will try to cover the basics in this section. There are three main functions that make up an e-mail system. First there is the Mail User Agent (MUA) which is the program a user actually uses to compose and read mails. Then there is the Mail Transfer Agent (MTA) that takes care of transferring messages from one computer to another. And last there is the Mail Delivery Agent (MDA) that takes care of delivering incoming mail to the user’s inbox. These three functions can be performed by separate programs, but they can also be combined in one or two programs. It is also possible to have different programs handle these functions for different types of mail. On Linux and Unix systems mutt is historically a very popular MUA. Like most traditional Linux programs it is text based. It is often used in combination with exim or sendmail as MTA and procmail as MDA. Even if you are planning to use a graphical mail program, it is important that a traditional MTA/MDA is also installed and correctly set up on your Ubuntu system. Reason is that various utilities running on the system 2 can send important notices by e-mail to inform the system administrator of (potential) problems or changes. For this reason the packages exim4 and mutt will be installed by default (provided you did not unse- lect the “standard” task during the installation). exim4 is a combination MTA/MDA that is relatively small but very flexible. By default it will be configured to only handle e-mail local to the system itself and e-mails addressed to the system administrator (root account) will be delivered to the regular user account created during the installation$^{3}$. When system e-mails are delivered they are added to a file in /var/mail/ account_name . The e-mails can be read using mutt . 2. Examples are: cron , quota , logcheck , aide , . . . 3. The forwarding of mail for root to the regular user account is configured in /etc/aliases . If no regular user account was created, the mail will of course be delivered to the root account itself. 76 8.5.1. Default E-Mail Configuration 8.5. Setting Up Your System To Use E-Mail