If you are one of those thousands of system administrators who manage the networks and computers of small to medium-sized companies and you are thinking of hosting your own e-mail service, this book is for you.
We will start with the most basic components of an e-mail system. Together those components will allow your users to send or receive mail to or from anyone on the Internet. This might be all you need, but many companies also want to provide their users with an accessible webmail service that people can use from home or when they are on the road. Another feature that many people unfortunately cannot be without today is proper protection against viruses spread via e-mail as well as the filtering of spam messages.
We will also cover the most important aspects of security to prevent unauthorized or malicious use of the server. We will then discuss how to retain an archive of all e-mails received or sent by the server. Finally, we shall describe a process to backup and restore the server to protect all messages against data loss.
This book will cover the major features of the software in question, which will give you a solid foundation to work from.
By the end of this book, you will have a functioning e-mail server suitable for most small companies.
As the technical platform for our endeavor, we have chosen the GNU/Linux operating system and a proven selection of free software tools that will help us achieve the goal of a secure and reliable e-mail server for smaller companies. The tools we have chosen are widely known and used, written by software professionals, and are supported by a large community of users.
In this very first chapter of the book, we start with what you need to know before you even start working on your server.
We discuss the advantages and disadvantages of running your own e-mail server.
Guidance is given for choosing the appropriate hardware and network connection needed for the server.
We give a brief introduction to the protocol used for exchanging mail over the Internet and the main protocols available to allow users to access their e-mails.
In order to correctly route e-mail, we discuss the configuration options required on the server connected to the Internet.
Finally, we provide a brief introduction to backup e-mail servers.
By the end of this chapter, you will have a basic understanding of the main components required to run an e-mail server.
Most Internet Service Providers (ISPs) already give customers the ability to send and receive e-mail on their servers, so why would we want to own and manage it by ourselves? As you are after all reading this book, you may already have your reasons, but let us examine this question and some possible answers to it.
The most important reason for hosting and managing your own e-mail server is control. For many organizations, e-mail is an important part of the Information Technology infrastructure. Keeping control over your e-mail has many advantages.
If a company has offices in multiple places, you have full freedom when choosing how to connect them. A virtual private network between the offices, Transport Layer Security (TLS) connections between the offices, a single server for all offices, one server per office, and so on.
By keeping your own messaging in-house, you can send messages to each other without having them travel across unsecured lines to and from the ISP. This also gives you a more reliable service if your Internet connection fails, and it avoids unnecessary latencies.
You are not dependent on the competence of the provider's staff. If you manage your own server and need to solve a difficult problem or implement a custom solution for something, you can. Or if necessary, you can hire a consultant to help you.
If the provider goes bankrupt, all of your data resides safely in your server room and on your backup media.
You are not subject to the limitations that our provider may set regarding, say, use of disk space or the maximum size of messages.
You can implement any policies for message archiving, antispam, or antivirus that you choose.
More control requires more responsibility and more knowledge, and that is where this book comes in.
These hopefully compelling arguments aside, there are also downsides to hosting your own e-mail server. This is a task that requires a certain level of knowledge and commitment, and so should not be undertaken by everyone. With your own server, you are not only responsible for the service you provide to your users, but you also have a responsibility towards the whole Internet community. An ill-configured e-mail server can help worms and spam to spread, which is not only is a disservice to the community but can also get your server blacklisted. Even though a properly set up server can run for years without requiring much maintenance, you must keep yourself reasonably updated and be prepared to act upon new threats that may arise. This is not meant to scare you off, but just to make you think carefully before embarking on this project.