Book Image

Linux Networking Cookbook

By : Agnello Dsouza, Gregory Boyce
5 (1)
Book Image

Linux Networking Cookbook

5 (1)
By: Agnello Dsouza, Gregory Boyce

Overview of this book

Linux can be configured as a networked workstation, a DNS server, a mail server, a firewall, a gateway router, and many other things. These are all part of administration tasks, hence network administration is one of the main tasks of Linux system administration. By knowing how to configure system network interfaces in a reliable and optimal manner, Linux administrators can deploy and configure several network services including file, web, mail, and servers while working in large enterprise environments. Starting with a simple Linux router that passes traffic between two private networks, you will see how to enable NAT on the router in order to allow Internet access from the network, and will also enable DHCP on the network to ease configuration of client systems. You will then move on to configuring your own DNS server on your local network using bind9 and tying it into your DHCP server to allow automatic configuration of local hostnames. You will then future enable your network by setting up IPv6 via tunnel providers. Moving on, we’ll configure Samba to centralize authentication for your network services; we will also configure Linux client to leverage it for authentication, and set up a RADIUS server that uses the directory server for authentication. Toward the end, you will have a network with a number of services running on it, and will implement monitoring in order to detect problems as they occur.
Table of Contents (19 chapters)
Linux Networking Cookbook
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Setting up DNS records for e-mail delivery


When configuring a properly set up mail server, there are a number of DNS records you need to set up in order to ensure that the system functions as expected. Some of these are defined in RFC974, which covers mail routing and the DNS system.

The main piece you need to understand is Mail Exchanger (MX) records. These records define how e-mail destined to a given domain should be handled. Without an MX record being defined, e-mail addressed to [email protected] would be sent to the domain.com A record, which is often an HTTP server. For some smaller sites, this may be reasonable if their HTTP server is also an SMTP server, but that is not always the case.

Rather than depending on the A record, you can instead use one or more MX records with defined priorities that point to A records which may be in or out of the domain you're configuring. For example, your e-mail could go to smtp.domain.com. Alternatively, if Google Apps handles your e-mail, you may...