What operating system would be suitable for a mail server of an organization having 1000 email accounts?
AnswerUse DeepOfix; a custom distribution (based on debian) that is specialized for email delivery.A list of features (copied and pasted from http://deeproot.in/deepofix/features)Simplified installation systemIntegrated server management systemWe ensure that a lack of prior GNU/Linux server administration experience is not a problem at all. The EasyPush Server Manager (our server management system) simplifies day-to-day server administration and monitoring tasks. EasyPush allows a server admin to build up upon their knowledge of server administration and learn more about GNU/Linux.Built-in LDAP supportdeepOfix is one of the first (and few) GNU/Linux operating systems that ship with built-in and pre-integrated support for LDAP. LDAP support in deepOfix goes beyond installation - in deepOfix LDAP is not just installed, but also configured as the default store for user account data and password information. LDAP support not only enables deepOfix to be highly scalable, but also ensure a large group of features that would otherwise have been impossible.Intelligent & flexible account managementSMTP / POP3 / IMAP ServicesdeepOfix allows you to have greater control with on how your mail sending and delivery (SMTP) services work. Additionally, it provides you with out-of-the-box POP3 and IMAP services to access your mailbox.Web-based emailPre-integrated anti-virus and anti-spam toolsdeepOfix does not require you to do anything extra to filter emails for spam or virus! The ClamAV anti-virus system ensures virus free mailboxes for users - even anti-virus signature updates are automated! The SpamAssassin-based anti-spam system ensures that you can control incoming spam. The server ships pre-configured with secure defaults that can be further optimised using our EasyPush Server Manager and best of all, our continued research and development ensures that your spam control system remains updated and capable enough to handle new and upcoming spam threats as well Centralised LDAP-based address booksGroups and Distribution ListsEmail fetch with multidrop supportFetch email from other mail servers?Mix catch-all, multi-drop and individual mail accounts?Work multiple protocols to fetch email - POP3, IMAP etc?Extensive customisation optionsGet your deepOfix server to work better for you: Know some sort of scripting (shell or Perl etc.)? Want to write quick add-ons for deepOfix to something more? EasyPush supports simple extensions via command-line programs and scriptsExperienced programmer and want to get deepOfix to do more? Weave your own code!AnswerFreeBSD, available for free download from http://www.freebsd.org/. FreeBSD powers a number of commercial web and mail hosting sites, including many of the servers at Yahoo! FreeBSD supports a number of popular mail servers, including sendmail, postfix, exim, and qmail, plus spam and virus filters, IMAP and POP servers for client access to mail, and any other email related utilities your heart may desire.A tutorial on how to create a mail server running FreeBSD, sendmail, and the University of Washington POP and IMAP server is available at:http://www.puresimplicity.net/~hemi/freebsd/sendmail.html Answer:Any server intended operating system: NT4, 2000 Server, 2003 Server, 2008 Server, OS/X, Linux, FreeBSD, NetBSD. The hard part about servers is matching the load (amount of work), the hardware (as low cost as possible yet still accomplish the goal), and the operating system (cost, ease of administration, stability and security) against your needs now and for a specific period of time into the future: a year, 2 years, 5 years. That's what infrastructure engineers do - they optimize the use of machines against load and future use.The best system to use is one that whomever is administering the system knows - you can have the best op system and if the admin can't use it right (not experienced with it) you might as well open your windows and doors to the world "come on in, get our data!" or go the users and say "sorry, the server will be going down all the time randomly, expect it."