Apple G0442 Mail Services, File system access controls, Cups print services, Core mail services

Compatibility in heterogeneous environments

Apple’s ACL implementation is compatible with the POSIX 1003e draft. This enables full interoperability with the native permissions of Windows Server 2003 and Windows XP, while maintaining compatibility with traditional UNIX le permissions. Such versatility makes Mac OS X Server the ultimate platform for le sharing in mixed-platform workows.

Mail services

•SMTP (Postx)

•POP and IMAP (Cyrus)

•Berkeley DB for indexing

•SSL/TLS encryption (OpenSSL)

•Junk mail ltering (SpamAssassin)

•Virus detection (ClamAV)

•Mailing lists (Mailman)

•Webmail (SquirrelMail)

Technology Overview 17

Mac OS X Server

File system access controls

Mac OS X Server v10.4 supports both traditional UNIX le permissions and access control lists, o!ering administrators an exceptional level of control over le and folder permissions.

Most UNIX- and Linux-based operating systems are constrained by the UNIX le permissions model, also known as Portable Operating System Interface (POSIX) per- missions. Standard UNIX le permissions allow you to assign one access privilege to the le’s owner, one to a group, and one to everyone on the network. Access by multiple users or multiple groups is not allowed, nor is ownership by a group. The traditional UNIX model also lacks some other important le access features. It supports only three permissions (read, write, and execute) and does not support permission inheritance, which enables new or copied les to automatically inherit the access controls of the parent directory.

To provide greater exibility in complex computing environments, Apple has added support for ACLs in Mac OS X Server v10.4. With le system ACLs, any le object can be assigned multiple users and groups, including groups within groups. Each le object can also be assigned both allow and deny permissions, as well as a granular set of permissions for administrative control, read, write, and delete operations. For added security, Mac OS X Server now supports a le permission inheritance model, ensuring that user permissions are inherited when les are moved to the server and rewritten when les are copied to the server.

CUPS print services

At the heart of the print services in Mac OS X Server is the Common UNIX Printing System (CUPS), an open source printing architecture that supports standard cross- platform print protocols, including IPP, LPR, SMB/CIFS, and AppleTalk PAP.

Using Open Directory and Workgroup Manager, Mac OS X Server provides centralized, directory-based management of printer resources. Printers can be assigned to any combination of users, groups, and computers, and print quotas can be enforced on a per-user and per-queue basis. Flexible queue management and remote monitoring tools allow management of high-volume, cross-platform printing for Mac, Windows, and Linux clients from a single, intuitive interface. Settings and access policies are stored in any LDAP server using Open Directory.

Mail Services

Mac OS X Server combines several robust technologies from the open source com- munity to deliver comprehensive, easy-to-use mail server solutions. Full support for Internet mail protocols—Internet Message Access Protocol (IMAP), Post O"ce Protocol (POP), and Simple Mail Transfer Protocol (SMTP)—ensures compatibility with standards- based mail clients on Mac, Windows, and Linux systems. With support for thousands of users per server and no per-user licensing fees, these high-performance mail services o!er signicant cost savings for small organizations and large enterprises alike.

Core mail services

Mac OS X Server uses the high-speed Postx server for SMTP messaging and the Cyrus mailbox server for scalable, enterprise-class POP and IMAP mail. Flexible mail storage makes it easy to scale the mail server to meet growing needs, and high- performance Berkeley DB indexing ensures continued responsiveness when clients access their mail, delete messages, and move les on the mail server. To protect your network mail services from unauthorized access or abuse, Mac OS X Server includes built-in SSL/TLS encryption, strong authentication, junk mail and virus ltering, and exible mail quota handling capabilities.