SockRedirector

Redirects TCP connections from one IP address and port to another.

I have used this tool for many years. It redirects the TCP traffic received on a local address/port to a port of a remote machine.

It is very useful in complex network architectures, where firewalls allow connections only from one specific machine to another: you can run SockRedirector on the trusted machine and reach the remote server through it.

The concept is very similar to a proxy, without being limited to HTTP connections and without the need to implement a SOCKS interface.

SockRedirector is written in Java and runs on Linux, Windows, macOS, AIX, AS/400 or any environment with a Java runtime. Native executables (built with GraalVM) are also available for Linux, macOS and Windows.

Requirements

• Java 11 or later to run the jar
• To build: JDK 25 and Maven (GraalVM 25 to build the native executable)

Build

# Runnable jar: target/SockRedirector-<version>-jar-with-dependencies.jar
mvn package

# Native executable (requires GraalVM): target/Sockredirector
mvn package -DskipNativeVersion=false

Run

Put a sockRedirector.ini file in the working directory and start the program:

java -jar SockRedirector-<version>-jar-with-dependencies.jar

Logs are written to the console and to logs/sockRedirector.log.

Documentation

sockRedirector.ini

The ini file is divided into one or more <redirection> sections. For each section you can define these parameters

key	type	default	value
source	string	mandatory	source ip to bind, listen on
sourceport	int	mandatory	source port to bind, listen on
destination	string	mandatory	destination host
destinationport	int	mandatory	destination port
log	boolean	false	dump the traffic of each connection under logs/
timeout	int	0	source socket timeout (seconds), 0 = no timeout
client	int	10	max pending connections on the source (backlog)
blocksize	int	64000	size of buffer to read from source and destination
inReadWait	long	0	pause before reading from destination (ms)
inWriteWait	long	0	pause before writing to source (ms)
outReadWait	long	0	pause before reading from source (ms)
outWriteWait	long	0	pause before writing to destination (ms)
randomKill	long	0	testing only: randomly close connections (about once every N seconds), 0 = disabled

Example

Configuration Example (sockRedirector.ini)

<redirection>
   <source>127.0.0.1</source>
   <sourceport>80</sourceport>
   <destination>1.1.1.1</destination>
   <destinationport>80</destinationport>
   <log>true</log>
   <timeout>0</timeout>
   <client>50</client>
   <inReadWait>0</inReadWait>
   <inWriteWait>0</inWriteWait>
   <outReadWait>0</outReadWait>
   <outWriteWait>1000</outWriteWait>
</redirection>

Admin console

While running, SockRedirector accepts these commands on standard input:

command	description
help	show the command list
exit	exit program
thread [filter]	list active connections
kill <id> [<id> ...]	close the given threads
pause <id> <readPause> <writePause>	set read/write pause (ms) on a flow thread

QUESTIONS AND DOCUMENTATION

For the full SockRedirector documentation, visit Deep Wiki.