Linux Server Security, Second Edition

This is the Title of the Book, eMatter Edition

Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.

Other File-Sharing Methods

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To use scp, however, you need prior knowledge of the remote system’s filesystem

layout and contents. While in many situations this isn’t a big deal, particularly when

using scp in scripts, it’s an annoying limitation in many others. Thus, sftp deserves a

place in the toolkits of SSH beginners and experts alike.

Note, however, that SSH doesn’t explicitly support anonymous/public file sharing

via either sftp or scp. It’s certainly possible, given hefty amounts of caution and test-

ing, to set up a nonprivileged account with an empty password and a closely watched

home directory for this purpose. (sshd has a configuration option called

PermitEmptyPasswords that is disabled by default but may be set to yes.) I consider

this to be playing with fire, however: SSH was designed for and excels at providing

secure, restricted access. Anonymous file services are not only the best use of conven-

tional FTP daemons such as vsftpd; such access is best provided by them.

Configuration and use of the OpenSSH version of the Secure Shell, including scp and

sftp, is covered in depth in Chapter 4.

rsync

Andrew Tridgell’s rsync is another useful file-transfer tool, one that has no encryp-

tion support of its own but is easily “wrapped” (tunneled) by encryption tools such

as