DNS & Spam database lookup

Spam Database Lookup
Check multiple RBL here
DNS report

Regarding Exchange/Linux/LDAP

SUSE Openexchange Under GPL
Real-life review of why MS Exchange sucks.

Exchange Functionality for Linux

Migrating from Exchange to OSER

Export contacts from Exchange server to LDAP

eMailman(sm) -- Conversion

Connecting POP And IMAP Clients To MS Exchange Server

Plugins:

ZideStore Server / ZideLook Outlook Plugin

Online game infrastructures

Online game infrastructures: Develop a high-level business description and identify patterns
READ IT! :-)