Silicon Graphics Gauntlet, Administrator'S Manual, Page: 65 / 306

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Chapter 5
5. Managing FTP Services
Sometimes the easiest way to transfer information from one machine to another is to
actually transfer the relevant files. The file transfer protocol (FTP) is one of several
protocols that make this possible. The Gauntlet firewall includes a proxy that securely
allows the transfer of files between trusted and untrusted networks.
This chapter explains the concepts behind the FTP proxy and how it works, how to
configure the proxy, and how to use FTP services. A section also discusses considerations
for running anonymous FTP servers.
Understanding the FTP Proxy
The Gauntlet FTP proxy is an application-level proxy that provides configurable access
control, authentication, and logging mechanisms.
The FTP proxy, which runs on the firewall, passes FTP requests through the firewall,
using rules you supply. You can configure the FTP proxy to allow file transfer activity
based on
• source IP address
• source hostname
• destination IP address
• destination hostname
• FTP command (for example, STOR and RETR)
Using these options, you can configure your firewall to allow specific hosts on outside
networks to transfer files to and from inside hosts. Employees working at specific
customer sites can access files on their workstations. Similarly, you can configure your
firewall to permit users on the inside network to copy files (using the FTP daemon RETR
command) from hosts on the outside network, but not place files (using the FTP daemon
STOR command) on these outside hosts.