Specifications

Debian GNU/Linux 4.0 (etch) / 5.0 (lenny)
Linux 2.6.29.4 (kernel x86_64, 32bit userland)
Apache 2.2.11
ProFTPd 1.3.2
Dovecot 1.1.15
SpamAssassin 3.2.5
exim 4.62
DirectAdmin 1.33.6

PHP 5.2.9 (+Zend Optimizer 3.3.3)
Unzip: /usr/bin/unzip
ImageMagick path: /usr/bin
Pear: /usr/local/lib/php

MySQL 5.1
port: 3306 (you must define hostnames in DirectAdmin which will be able to access MySQL)
Unix socket: /tmp/mysql.sock

SMTP
port: 25
port: 587 (if your ISP blocks outgoing port 25)

IMAP/IMAPs
port: 143
ssl port: 993

POP3/POP3s
port: 110
ssl port: 995