30-05-2012, 01:02 PM
Mail Server
Mail Server.docx (Size: 1.47 MB / Downloads: 49)
A mail server is the computerized equivalent of your friendly neighborhood mailman. Every email that is sent passes through a series of mail servers along its way to its intended recipient. Although it may seem like a message is sent instantly - zipping from one PC to another in the blink of an eye - the reality is that a complex series of transfers takes place
Types of Mail Servers
SMTP
POP3
IMAP
Sendmail
Sendmail's core purpose, like other MTAs, is to safely transfer email among hosts, usually using the SMTP protocol. However, Sendmail is highly configurable, allowing control over almost every aspect of how email is handled, including the protocol used. Many system administrators elect to use Sendmail as their MTA due to its power and scalability.
Postfix
Originally developed at IBM by security expert and programmer Wietse Venema, Postfix is a Sendmail-compatible MTA that is designed to be secure, fast, and easy to configure.
To improve security, Postfix uses a modular design, where small processes with limited privileges are launched by a master daemon. The smaller, less privileged processes perform very specific tasks related to the various stages of mail delivery and run in a change rooted environment to limit the effects of attacks
Domain Name Server (DNS)
DNS associates hostnames with their respective IP addresses, so that when users want to connect to other machines on the network, they can refer to them by name, without having to remember IP addresses
Apache HTTP Server
The Apache HTTP Server is a robust, commercial-grade open source Web server developed by the Apache Software Foundation
Features of Apache HTTP Server 2.
Improved caching modules (mod_cache, mod_disk_cache, mod_mem_cache).
A new structure for authentication and authorization support, replacing the authentication modules provided in previous versions.
Support for proxy load balancing (mod_proxy_balancer)
* support for handling large files (namely, greater than 2GB) on 32-bit platforms
* The mod_cern_meta and mod_asis modules are no longer loaded by default.
* The mod_ext_filter module is now loaded by default.
Squirrelmail
SquirrelMail is a standards-based webmail package written in PHP. It includes built-in pure PHP support for the IMAP and SMTP protocols, and all pages render in pure HTML 4.0 (with no JavaScript required) for maximum compatibility across browsers. It has very few requirements and is very easy to configure and install.
System Architecture of Mail Server
MUA – Mail User Agent UDP – User Datagram Protocol
MTA – Mail Transport Agent SMTP – Simple Mail Transfer Protocol
DNS – Domain Name Server POP – Post Office Protocol
IMAP – Intenet Mail Access Protocol
SOFTWARE REQUIRMENTS
Berkeley Internet Name Domain (BIND)
Nameserver Zones
Zones are defined on authoritative nameservers through the use of zone files (which describe the namespace of that zone), the mail servers to be used for a particular domain or sub-domain, and more. Zone files are stored on primary nameservers (also called master nameservers), which are truly authoritative and where changes are made to the files, and secondary nameservers (also called slave nameservers), which receive their zone files from the primary nameservers
Nameserver Types
There are four primary nameserver configuration types:
Master : Stores original and authoritative zone records for a namespace, and answers queries about the namespace from other nameservers.
Slave :Answers queries from other nameservers concerning namespaces for which it is
considered an authority.