ss-tunnel(1)
============

NAME
----
ss-tunnel - shadowsocks tools for local port forwarding, libev port

SYNOPSIS
--------
*ss-tunnel*
 [-uUv6] [-h|--help]
 [-s <server_host>] [-p <server_port>] [-l <local_port>]
 [-k <password>] [-m <encrypt_method>] [-f <pid_file>]
 [-t <timeout>] [-c <config_file>] [-i <interface>]
 [-b <local_address>] [-a <user_name>] [-n <nofile>]
 [-L addr:port] [--mtu <MTU>] [--mptcp] [--reuse-port] [--no-delay]
 [--plugin <plugin_name>] [--plugin-opts <plugin_options>]
 [--key <key_in_base64>]

DESCRIPTION
-----------
*Shadowsocks-libev* is a lightweight and secure socks5 proxy.
It is a port of the original shadowsocks created by clowwindy.
*Shadowsocks-libev* is written in pure C and takes advantage of libev to
achieve both high performance and low resource consumption.

*Shadowsocks-libev* consists of five components.
`ss-tunnel`(1) is a tool for local port forwarding.
See 'OPTIONS' section for special option needed by `ss-tunnel`(1).
For more information, check out `shadowsocks-libev`(8).

OPTIONS
-------
-s <server_host>::
Set the server's hostname or IP.

-p <server_port>::
Set the server's port number.

-l <local_port>::
Set the local port number.

-k <password>::
--password <password>::
Set the password. The server and the client should use the same password.

--key <key_in_base64>::
Set the key directly. The key should be encoded with URL-safe Base64.

-m <encrypt_method>::
Set the cipher.
+
*Shadowsocks-libev* accepts 22 different ciphers:
+
2022-blake3-aes-128-gcm, 2022-blake3-aes-256-gcm,
2022-blake3-chacha20-poly1305,
aes-128-gcm, aes-192-gcm, aes-256-gcm,
rc4-md5, aes-128-cfb, aes-192-cfb, aes-256-cfb,
aes-128-ctr, aes-192-ctr, aes-256-ctr, bf-cfb,
camellia-128-cfb, camellia-192-cfb, camellia-256-cfb,
chacha20-ietf-poly1305, xchacha20-ietf-poly1305,
salsa20, chacha20 and chacha20-ietf.
+
The default cipher is 'chacha20-ietf-poly1305'.
+
The '2022-blake3-*' ciphers implement Shadowsocks 2022 (SIP022) and are
the recommended choice: they provide full replay protection and
session-based UDP relay. They require a base64-encoded pre-shared key of
exactly the cipher's key size (16 bytes for 2022-blake3-aes-128-gcm, 32
bytes for the others) given with *-k*; passwords are not accepted and are
never stretched into a key. Generate one with `openssl rand -base64 32`.
+
If built with PolarSSL or custom OpenSSL libraries, some of
these ciphers may not work.

-a <user_name>::
Run as a specific user.

-f <pid_file>::
Start shadowsocks as a daemon with specific pid file.

-t <timeout>::
Set the socket timeout in seconds. The default value is 60.

-c <config_file>::
Use a configuration file.
+
Refer to `shadowsocks-libev`(8) 'CONFIG FILE' section for more details.

-n <number>::
Specify max number of open files.
+
Only available on Linux.

-i <interface>::
Send traffic through specific network interface.
+
For example, there are three interfaces in your device,
which is lo (127.0.0.1), eth0 (192.168.0.1) and eth1 (192.168.0.2).
Meanwhile, you configure `ss-tunnel` to listen on 0.0.0.0:8388 and bind to eth1.
That results the traffic go out through eth1, but not lo nor eth0.
This option is useful to control traffic in multi-interface environment.

-b <local_address>::
Specify the local address to use while this client is making outbound 
connections to the server.

-u::
Enable UDP relay.

-U::
Enable UDP relay and disable TCP relay.

-6::
Resolve hostname to IPv6 address first.

-L <addr:port>::
Specify destination server address and port for local port forwarding.
+
Only used and available in tunnel mode.

--mtu <MTU>::
Specify the MTU of your network interface.

--mptcp::
Enable Multipath TCP.
+
Only available with MPTCP enabled Linux kernel.

--reuse-port::
Enable port reuse.
+
Only available with Linux kernel > 3.9.0.

--no-delay::
Enable TCP_NODELAY.

--tcp-incoming-sndbuf <size>::
Set TCP send buffer size for incoming connections.

--tcp-incoming-rcvbuf <size>::
Set TCP receive buffer size for incoming connections.

--tcp-outgoing-sndbuf <size>::
Set TCP send buffer size for outgoing connections.

--tcp-outgoing-rcvbuf <size>::
Set TCP receive buffer size for outgoing connections.

--plugin <plugin_name>::
Enable SIP003 plugin. (Experimental)

--plugin-opts <plugin_options>::
Set SIP003 plugin options. (Experimental)

-v::
Enable verbose mode.

-h|--help::
Print help message.

EXAMPLE
-------
`ss-tunnel`(1) can be used to forward DNS queries to a remote DNS server
through the shadowsocks tunnel. Here is an example:

....
# Forward local UDP port 5353 to 8.8.8.8:53 through the ss-server
ss-tunnel -s example.com -p 12345 -l 5353 -k foobar -m aes-256-cfb -L 8.8.8.8:53 -u

# Then configure your system to use 127.0.0.1:5353 as the DNS server
dig @127.0.0.1 -p 5353 www.google.com
....

SEE ALSO
--------
`ss-local`(1),
`ss-server`(1),
`ss-redir`(1),
`ss-manager`(1),
`shadowsocks-libev`(8),
`iptables`(8),
/etc/shadowsocks-libev/config.json