Are you looking for email Server for your domain ?
Are you looking for Bulk email Server or SMTP Server to send Email Marketing Campaigns ??... You are on right here.
I'll used open source software make your VPS or Dedicated Server convert to user friendly Email Server .
SMTP service - Postfix
POP3/POP3S, IMAP/IMAPS, Managesieve service - Dovecot
Web server- Apache
Database - MySql with phpmyadmin
Storing application data and/or mail accounts - MySQL
Storing mail accounts - OpenLDAP
Spam and virus scanning- Amavisd, SpamAssassin, ClamAV.
Webmai l- Roundcube