FTP Proxy - File Transfer Protocol Proxy

What is FTP Proxy?

An FTP Proxy is a server that acts as an intermediary between a client and an FTP server. It forwards FTP requests from clients to external or internal FTP servers, often applying rules, logging, or authentication in the process.

Why is FTP Proxy useful?

  • Adds security by controlling and filtering FTP traffic.

  • Enables auditing and logging of FTP sessions.

  • Helps enforce network policies (e.g., access control).

  • Allows FTP traffic through firewalls that may block direct FTP communication.

  • Supports NAT traversal in restrictive network environments.

How it works?

  • The client sends an FTP request to the FTP proxy instead of directly to the FTP server.

  • The proxy analyzes, logs, and forwards the request to the target FTP server.

  • The proxy can rewrite commands, inspect data, or enforce authentication.

  • Responses from the server pass back through the proxy to the client.

Where is FTP Proxy used?

  • In corporate or enterprise networks to monitor and control file transfers.

  • In firewall-protected environments to facilitate FTP communication.

  • In secure zones where FTP access must be strictly controlled.

  • In ISPs or security appliances offering managed FTP access.

Which OSI layer does this protocol belong to?

  • FTP Proxy operates at the Application Layer (Layer 7) of the OSI model.

  • It understands and processes FTP commands and responses.

IS FTP Proxy windows specific?

  • No, FTP proxy is not Windows-specific.

  • It can be implemented on any operating system with compatible proxy software (e.g., Blue Coat, WinGate, or Squid with FTP support).

IS FTP Proxy Linux Specific?

  • No, FTP proxy is not Linux-specific.

  • It is commonly deployed on Linux servers but also runs on Windows, BSD, and other platforms.

Which Transport Protocol is used by FTP Proxy?

  • FTP Proxy uses TCP, just like the FTP protocol it supports.

  • It relays control and data connections via TCP streams.

Which Port is used by FTP Proxy?

  • By default, it handles connections on: * Port 21 for FTP control. * Port 20 (or dynamic ports) for data transfer.

  • The proxy itself might be configured to listen on custom ports depending on network setup.

Is FTP Proxy using Client server model?

  • Yes, FTP Proxy uses the client-server model.

  • The proxy acts as a server to the client and as a client to the actual FTP server.

  • It intermediates all communication between the two.

Topics in this section,

  • In this section, you are going to learn

  • Terminology

  • Version Info

  • rfc details

  • setup

  • setup

  • packet details

  • usecases

  • features

  • Reference links