Technical data

Brocade ServerIron ADX Advanced Server Load Balancing Guide 69
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Other transparent cache switching options
2
Figure 12 shows passive FTP packet flow. Using passive FTP, a PASV command is sent instead of a
PORT command. Instead of specifying a port that the server can send to, the PASV command asks
the server to specify a port it wishes to use for the Data Channel connection. The server replies on
the Control Channel with the port number which the client then uses to initiate an exchange on the
Data Channel. The server will thus always be responding to client-initiated requests on the Data
Channel and the firewall can correlate these.
FIGURE 12 Traffic flow for passive FTP
Topologies supported
The following topologies are supported by passive FTP for TCS on the ServerIron ADX:
• Basic TCS
• TCS with spoofing