Set up a mail server

Steps In Setting Up A Linux Mail Server

A functional mail server is an important part of many Linux server systems. Mail servers allow individuals, groups, and enterprises to send and receive electronic mail (e-mail) for its own use or as part of an Internet Service Provider's features. However, a fully functional mail server system involves several different, but related pieces of software all working together. The following should be a guide to the process of installing and setting up a mail server system. It is not completely comprehensive as there are different trails that one can take based upon individual or organization choices.

I. Install and set up DNS (Domain Name Server) for the server.
The first step in setting up a mail server on a Linux system is to install and set up a DNS system. Bind is a common program for this purpose. The purpose of a functional DNS is that the Internet as a whole will know who you are and where other mail servers can deliver mail addressed to your domain. Part of the set up of a DNS is to obtain and register your systems domain name.

II. Install and set up the MTA (Mail Transport Agent) for the server.
The task of the MTA in a mail server is to be the post office for all of the e-mail sent and received on the server's network and mail coming and going from and to other domains on the Internet. Postfix is a common MTA on Linux servers.

III. Install and set up the MUA (Mail User Agent) for the server.
The MUA is the program that allows mail system users to remotely access their e-mail accounts through other mail clients such as Thunderbird, Eudora, Evolution, or Microsoft Outlook. Mail clients must be authorized when they request mail for a user and are often set up to use encryption so that others cannot read the messages in transit. Dovecot is a common MUA for Linux servers and it integrates itself with an MTA such as Postfix. POP and IMAP are two forms of mail handling through an MUA.

IV. Install and set up Security (PAM, TLS) and Encryption (SSL certification) for the server.
In order to protect the mail server from unauthorized use (SPAM) and to protect the rest of the mail server system, one can install authorization software such as PAM and TLS so that users must present proper credentials in order to gain access to the MUA. The use of different password and user database methods are the area of PAM and TLS. In addition, it is also good to use SSL certification so that the MUA clients and other MTA's can trust your mail server and you can trust theirs as safe mail pathways.

V. Install and set up SPAM and Anti-virus protection for the server.
SPAM is a concern among many mail system administrators. There are also laws at the country and local levels that one might be required to comply with in order to have other MTA's accept e-mail from your server. In addition, even thought Linux software is virus resistant, e-mails are a method of infecting the mail user's computer. Spamassassin is a common Linux spam filter. Clamav is a common anti-virus scanner. Amavis is a software that integrates both the spam filter and anti-virus filter into one package.

VI. Install and set up a web-mail client for the server.
Many users of electronic mail check for new mail at places other than their desktop or laptop computers. In addition, they sometimes need to check their e-mail when they are not at their own computer at all. For this type of application, the mail server system needs a web-mail application. With a web-mail application, users can send and receive e-mail anywhere they have access to the Internet and a web browser. There are several web-mail programs in use on Linux systems; Squirrelmail is one example. Web-mail applications can go far beyond just sending and receiving e-mail for the user. They can also have additional features such as out-of-office set up, e-mail password change, and access to user or group calendars.

VII. Install and set up out-of-office responder for the server.
In addition to sending and receiving e-mail, some users prefer to have their e-mail automatically responded to while they are out of their office, on vacation, or otherwise not able to check for e-mail. Another feature of an autoresponder is also to forward important mail to other users so that messages do not languish while one is not able to send and receive mail.