What is the difference between Active and Passive FTP? Which one does BC-EDI use by default?
Article ID: KB0091476
Updated On:
| Products | Versions |
|---|---|
| TIBCO BusinessConnect EDI Protocol Powered by Instream | - |
| Not Applicable | - |
Description
Resolution:
Active FTP:
In active mode, the FTP client connects from a random unprivileged port (N > 1024) to the FTP
server's command port, port 21(assuming default). Then, the client starts listening to port N+1
and sends the FTP command PORT N+1 to the FTP server. The server will then connect back to the
client's specified data port from its local data port, which is port 20 (assuming the default value).
From the server-side firewall's standpoint, to support active mode FTP the following
communication channels need to be opened:
FTP server's port 21 from anywhere (Client initiates connection)
FTP server's port 21 to ports > 1024 (Server responds to client's control port)
FTP server's port 20 to ports > 1024 (Server initiates data connection to client's data port)
FTP server's port 20 from ports > 1024 (Client sends ACKs to server's data port)
Passive FTP:
In passive mode, the FTP client initiates both connections to the server, solving the problem of
firewalls filtering the incoming data port connection to the client from the server. When opening
an FTP connection, the client opens two random unprivileged ports locally (N > 1024 and N+1). The
first port contacts the server on port 21, but instead of then issuing a PORT command and
allowing the server to connect back to its data port, the client will issue the PASV command. The
result of this is that the server then opens a random unprivileged port (P > 1024) and sends the
PORT P command back to the client. The client then initiates the connection from port N+1 to port
P on the server to transfer data.
BC-EDI uses passive FTP connection by default when connecting to FTP server to get the files from Trading partner. In EDI protocol plugin version 2.2.0 and later, BC can be configured to use either Active or Passive mode when connecting to FTP servers, using a property. Please refer to the product documentation for addtional information.
Active FTP:
In active mode, the FTP client connects from a random unprivileged port (N > 1024) to the FTP
server's command port, port 21(assuming default). Then, the client starts listening to port N+1
and sends the FTP command PORT N+1 to the FTP server. The server will then connect back to the
client's specified data port from its local data port, which is port 20 (assuming the default value).
From the server-side firewall's standpoint, to support active mode FTP the following
communication channels need to be opened:
FTP server's port 21 from anywhere (Client initiates connection)
FTP server's port 21 to ports > 1024 (Server responds to client's control port)
FTP server's port 20 to ports > 1024 (Server initiates data connection to client's data port)
FTP server's port 20 from ports > 1024 (Client sends ACKs to server's data port)
Passive FTP:
In passive mode, the FTP client initiates both connections to the server, solving the problem of
firewalls filtering the incoming data port connection to the client from the server. When opening
an FTP connection, the client opens two random unprivileged ports locally (N > 1024 and N+1). The
first port contacts the server on port 21, but instead of then issuing a PORT command and
allowing the server to connect back to its data port, the client will issue the PASV command. The
result of this is that the server then opens a random unprivileged port (P > 1024) and sends the
PORT P command back to the client. The client then initiates the connection from port N+1 to port
P on the server to transfer data.
BC-EDI uses passive FTP connection by default when connecting to FTP server to get the files from Trading partner. In EDI protocol plugin version 2.2.0 and later, BC can be configured to use either Active or Passive mode when connecting to FTP servers, using a property. Please refer to the product documentation for addtional information.
Issue/Introduction
What is the difference between Active and Passive FTP? Which one does BC-EDI use by default?
Environment
Product: TIBCO BusinessConnect EDI Protocol
Version: All
OS: All
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