File eXchange Protocol
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Internet protocol suite |
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Application layer |
Transport layer |
Internet layer |
Link layer |
File eXchange Protocol (FXP or FXSP) is a method of data transfer which uses FTP to transfer data from one remote server to another (inter-server) without routing this data through the client's connection. Conventional FTP involves a single server and a single client; all data transmission is done between these two. In the FXP session, a client maintains a standard FTP connection to two servers, and can direct either server to connect to the other to initiate a data transfer. The advantage of using FXP over FTP is evident when a high-bandwidth server demands resources from another high-bandwidth server, but only a low-bandwidth client, such as a network administrator working away from location, has the authority to access the resources on both servers.
Risk
Enabling FXP support can make a server vulnerable to an
FXP over SSL
Some
Technical
Although FXP is often considered a distinct protocol, it is in fact merely an extension of the FTP protocol and is specified in
User-PI - Server A (Dest) User-PI - Server B (Source) ------------------ ------------------ C->A : Connect C->B : Connect C->A : PASV A->C : 227 Entering Passive Mode. A1,A2,A3,A4,a1,a2 C->B : PORT A1,A2,A3,A4,a1,a2 B->C : 200 Okay C->A : STOR C->B : RETR
B->A : Connect to HOST-A, PORT-a
References
This "protocol" is
- RFC 114.
See also
- File Transfer Protocol (FTP)
- Comparison of FTP client software
- List of FTP server software
- Trivial File Transfer Protocol (TFTP)
- SSH
- FTPS (FTPS), FTP run over SSL
- RFC 913