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Proxy Command

Start the VIIPER USBIP proxy for traffic inspection and logging.

Usage

viiper proxy --upstream=<address> [OPTIONS]

Description

The proxy command starts VIIPER in proxy mode, sitting between a USBIP client and a USBIP server.
VIIPER intercepts and logs all USB traffic passing through, without handling the devices directly.

This is useful for reverse engineering USB protocols and understanding how devices communicate.

Options

--listen-addr

Proxy listen address (where clients connect).

Default: :3241
Environment Variable: VIIPER_PROXY_ADDR

Example:

viiper proxy --listen-addr=:9000 --upstream=192.168.1.100:3240

--upstream

Required. Upstream USBIP server address (where real devices are).

Environment Variable: VIIPER_PROXY_UPSTREAM

Example:

viiper proxy --upstream=192.168.1.100:3240

--connection-timeout

Connection timeout for proxy operations.

Default: 30s
Environment Variable: VIIPER_PROXY_TIMEOUT

Example:

viiper proxy --upstream=192.168.1.100:3240 --connection-timeout=60s

Examples

Basic Proxy

Start proxy between local clients and remote USBIP server:

viiper proxy --upstream=192.168.1.100:3240

Clients connect to localhost:3241, traffic is proxied to 192.168.1.100:3240.

Custom Listen Address

Start proxy on a different port:

viiper proxy --listen-addr=:9000 --upstream=192.168.1.100:3240

Clients connect to localhost:9000, traffic is proxied to 192.168.1.100:3240.

With Raw Packet Logging

Capture all USB traffic for reverse engineering:

viiper proxy --upstream=192.168.1.100:3240 --log.raw-file=usb-capture.log

All USB packets will be logged to usb-capture.log.

With Debug Logging

Enable debug logging to see proxy operations:

viiper proxy --upstream=192.168.1.100:3240 --log.level=debug

Use Cases

Reverse Engineering

Intercept USB traffic between a client and server to understand device protocols:

viiper proxy --upstream=real-server:3240 --log.raw-file=device-capture.log

Traffic Analysis

Monitor USB communication for debugging:

viiper proxy --upstream=real-server:3240 --log.level=trace

Network Inspection

Route USB traffic through VIIPER to inspect and log all operations:

viiper proxy --upstream=real-server:3240 --log.level=debug --log.raw-file=traffic.log

Proxy Architecture

USBIP Client  →  VIIPER Proxy  →  USBIP Server (real devices)
                      ↓
              Logs/Captures Traffic

VIIPER sits in the middle, forwarding all traffic while logging packets for inspection.

See Also