Mac OS X Server v10.5 and v10.6 use SpamAssassin to filter "spam" from inbound messages; SpamAssassin includes a rule that increases the spam score for any inbound message sent on or after January 1, 2010.
This increased score may cause some inbound messages sent on or after January 1, 2010 to be inadvertently filtered as spam.

Aperture 3.0.2 is an update for Aperture 3. Aperture 3 is a paid upgrade for Aperture.

In Mac OS X v10.6 and later, the search order of DNS servers specificed in Network preferences is dynamic, so that servers that don’t respond are moved to the end of the search order.  This provides performance and reliability improvements over previous Mac OS X versions, but it can lead to unexpected results where a strict search order is required in Mac OS X v10.6.
With Mac OS X v10.6.3 and later, DNS servers can be searched in a strict order by making a change to the mDNSResponder plist as an administrator. Learn how in this advanced article.

Learn more about TCP and UDP ports used by Apple products, such as Mac OS X, Mac OS X Server, AppleShare IP, Network Assistant, Apple Remote Desktop, Macintosh Manager, and MobileMe. Many of these are referred to as "well known" industry standard ports.
Note: Mac OS X v10.5 Leopard and later includes a new technology called the Application Firewall which is different from a port-based firewall.

As described here, Security Update 2010-002 for Mac OS X Server v10.5.8 includes an update to the Cyrus SASL library. The sasl_encode64() function now requires a buffer one byte larger than it did in previous versions.

This change provides enhanced security, but it may also cause legitimate software that relies on the previous buffer size to not work as expected.
If this occurs you will see the following message in the system.log:

sasl_encode64: This function now NUL terminates.  Please pass in a buffer size large enough to accommodate the NUL.