Specifications

80 Chapter 5 FTP Service
On-the-Fly File Conversion
FTP service in Mac OS X Server allows users to request compressed or decompressed
versions of information on the server. A file-name suffix such as “.Z” or “.gz” indicates
that the file is compressed. If a user requests a file called “Hamlet.txt” and the server
only has a file named “Hamlet.txt.Z,” it knows that the user wants the decompressed
version, and delivers it to the user in that format.
In addition to standard file compression formats, FTP in Mac OS X Server has the ability
to read files from either HFS or non-HFS volumes and convert the files to MacBinary
(.bin) format. MacBinary is one of the most commonly used file compression formats
for the Macintosh operating system.
The table below shows common file extensions and the type of compression they
designate.
Files With Resource Forks
You can encourage Mac OS X clients to take advantage of on-the-fly conversion to help
them transfer files created using older file systems that store information in resource
forks. If you enable MacBinary and disk image auto-conversion in FTP service settings,
files with resource forks will be listed as .bin files on the FTP clients. When a client asks
to have one of these files transferred, on-the-fly conversion will recognize the .bin suffix
and convert the file to a genuine .bin file for transfer.
Kerberos Authentication
FTP supports Kerberos authentication. You choose the authentication method using
the General pane of the FTP service settings in Server Admin. See “Configuring General
Settings” on page 83.
FTP service specifications
• Maximum number of connected users (the default setting is 50 for authenticated
users and 50 for anonymous users): 1000
• FTP port number: 21
• Number of failed login attempts before user is disconnected: 3
File extension What it means
.gz DEFLATE compression
.Z UNIX compress
.bin MacBinary encoding
.tar UNIX tar archive
.tZ UNIX compressed tar archive
.tar.Z UNIX compressed tar archive
.crc UNIX checksum file
.dmg Mac OS X disk image