Book Image

Linux Email

Book Image

Linux Email

Overview of this book

Many businesses want to run their email servers on Linux for greater control and flexibility of corporate communications, but getting started can be complicated. The attractiveness of a free-to-use and robust email service running on Linux can be undermined by the apparent technical challenges involved. Some of the complexity arises from the fact that an email server consists of several components that must be installed and configured separately, then integrated together. This book gives you just what you need to know to set up and maintain an email server. Unlike other approaches that deal with one component at a time, this book delivers a step-by-step approach across all the server components, leaving you with a complete working email server for your small business network. Starting with a discussion on why you should even consider hosting your own email server, the book covers setting up the mail server. We then move on to look at providing web access, so that users can access their email out of the office. After this we look at the features you'll want to add to improve email productivity: virus protection, spam detection, and automatic email processing. Finally we look at an essential maintenance task: backups. Written by professional Linux administrators, the book is aimed at technically confident users and new and part-time system administrators. The emphasis is on simple, practical and reliable guidance. Based entirely on free, Open Source software, this book will show you how to set up and manage your email server easily.
Table of Contents (15 chapters)
Linux E-mail
Credits
About the Authors
About the Reviewers
Preface

Enabling relaying for authenticated clients


If authentication has been successful, we just have to tell Postfix to allow relaying of messages for those who have been authenticated. This is done by editing main.cf and adding the permit_sasl_authenticated option to your list of restrictions in smtpd_recipient_restrictions like this:

smtpd_recipient_restrictions =
...
permit_sasl_authenticated
permit_mynetworks
reject_unauth_destination
...

Reload Postfix and start testing with a real mail client. If possible, ensure that its IP address is not part of mynetworks, as Postfix might be allowed to relay for that reason and not because SMTP AUTH worked out. You might want to limit relaying to the server only during the test. Change the mynetwork_classes = host setting so that clients from other machines automatically will not be a part of the Postfix network.

If you still experience problems with SMTP AUTH, take a look at saslfinger (http://postfix.state-of-mind.de/patrick.koetter/saslfinger/)....