# shadowsocks-libev(8)

## NAME

shadowsocks-libev - a lightweight and secure socks5 proxy

## SYNOPSIS

ss-local|ss-redir|ss-server|ss-tunnel|ss-manager [-s <server_host>] [-p <server_port>] [-l <local_port>] [-k <password>] [-m <encrypt_method>] [-f <pid_file>] [-t <timeout>] [-c <config_file>]

## 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. One is `ss-server`(1) that runs on a remote server to provide secured tunnel service. `ss-local`(1) and `ss-redir`(1) are clients on your local machines to proxy traffic(TCP/UDP or both). `ss-tunnel`(1) is a tool for local port forwarding.

While `ss-local`(1) works as a standard socks5 proxy, `ss-redir`(1) works as a transparent proxy and requires netfilter’s NAT module. For more information, check out the EXAMPLE section.

`ss-manager`(1) is a controller for multi-user management and traffic statistics, using UNIX domain socket to talk with `ss-server`(1). Also, it provides a UNIX domain socket or IP based API for other software. About the details of this API, please refer to the PROTOCOL section.

## OPTIONS

-s <server_host>

  Set the server’s hostname or IP.

-l <local_port>

  Set the local port number.

  Not available in server nor manager mode.

-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.

  Not available in manager mode.

-m <encrypt_method>

  Set the cipher.

  Shadowsocks-libev accepts 19 different ciphers:

  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.

  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.

-n <number>

  Specify max number of open files.

  Not available in manager mode.

  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 shadowsocks-libev 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.

  Not available in redir mode.

-b <local_address>

  Specify the local address to bind.

  For servers: Specify the local address to use while this server is making outbound connections to remote servers on behalf of the clients.

  For clients: Specify the local address to use while this client is making outbound connections to the server.

  Not available in manager mode.

-u

  Enable UDP relay.

  TPROXY is required in redir mode. You may need root permission.

-U

  Enable UDP relay and disable TCP relay.

  Not available in local mode.

-T

  Use tproxy instead of redirect (for tcp).

  Only available in redir mode.

-L <addr:port>

  Specify destination server address and port for local port forwarding.

  Only available in tunnel mode.

-d <addr>

  Setup name servers for internal DNS resolver (libc-ares). The default server is fetched from /etc/resolv.conf.

  Only available in server and manager mode.

--fast-open

  Enable TCP fast open.

  Not available in redir nor tunnel mode, with Linux kernel > 3.7.0.

--reuse-port

  Enable port reuse.

  Only available with Linux kernel > 3.9.0.

--no-delay

  Enable TCP_NODELAY.

--acl <acl_config>

  Enable ACL (Access Control List) and specify config file.

  Not available in redir nor tunnel mode.

--manager-address <path_to_unix_domain>

  Specify UNIX domain socket address.

  Only available in server and manager mode.

--executable <path_to_server_executable>

  Specify the executable path of `ss-server`.

  Only available in manager mode.

-v

  Enable verbose mode.

-h|--help

  Print help message.

## CONFIG FILE

The config file is written in JSON and easy to edit.

The config file equivalent of command line options is listed as example below.

Command line | JSON
--- | ---
-s some.server.net | "server": "some.server.net"
-s some.server.net -p 1234 (client) | "server": "some.server.net:1234"
-p 1234 | "server_port": "1234"
-b 0.0.0.0 | "local_address": "0.0.0.0"
-b 10.0.0.2 | "local_ipv4_address": "10.0.0.2"
-b 2620:129:35::33 | "local_ipv6_address": "2620:129:35::33"
-l 4321 | "local_port": "4321"
-k "PasSworD" | "password": "PasSworD"
-m "aes-256-cfb" | "method": "aes-256-cfb"
-t 60 | "timeout": 60
-a nobody | "user": "nobody"
--acl "/path/to/acl" | "acl": "/path/to/acl"
--fast-open | "fast_open": true
--reuse-port | "reuse_port": true
--no-delay | "no_delay": true
--plugin "obfs-server" | "plugin": "obfs-server"
--plugin-opts "obfs=http" | "plugin_opts": "obfs=http"
-6 | "ipv6_first": true
-n "/etc/nofile" | "nofile": "/etc/nofile"
-d "8.8.8.8" | "nameserver": "8.8.8.8"
-L "somedns.net:53" | "tunnel_address": "somedns.net:53"
-u | "mode": "tcp_and_udp"
-U | "mode": "udp_only"
no "-u" nor "-U" options (default) | "mode": "tcp_only"
-T | "tcp_tproxy": true
(only in ss-manager’s config) | "port_password": {"1234":"PasSworD"}

## EXAMPLE

`ss-redir` requires netfilter’s NAT function. Here is an example:

    # Create new chain
    iptables -t nat -N SHADOWSOCKS
    iptables -t mangle -N SHADOWSOCKS

    # Ignore your shadowsocks server's addresses
    # It's very IMPORTANT, just be careful.
    iptables -t nat -A SHADOWSOCKS -d 123.123.123.123 -j RETURN

    # Ignore LANs and any other addresses you'd like to bypass the proxy
    # See Wikipedia and RFC5735 for full list of reserved networks.
    # See ashi009/bestroutetb for a highly optimized CHN route list.
    iptables -t nat -A SHADOWSOCKS -d 0.0.0.0/8 -j RETURN
    iptables -t nat -A SHADOWSOCKS -d 10.0.0.0/8 -j RETURN
    iptables -t nat -A SHADOWSOCKS -d 127.0.0.0/8 -j RETURN
    iptables -t nat -A SHADOWSOCKS -d 169.254.0.0/16 -j RETURN
    iptables -t nat -A SHADOWSOCKS -d 172.16.0.0/12 -j RETURN
    iptables -t nat -A SHADOWSOCKS -d 192.168.0.0/16 -j RETURN
    iptables -t nat -A SHADOWSOCKS -d 224.0.0.0/4 -j RETURN
    iptables -t nat -A SHADOWSOCKS -d 240.0.0.0/4 -j RETURN

    # Anything else should be redirected to shadowsocks's local port
    iptables -t nat -A SHADOWSOCKS -p tcp -j REDIRECT --to-ports 12345

    # Add any UDP rules
    ip rule add fwmark 0x01/0x01 table 100
    ip route add local 0.0.0.0/0 dev lo table 100
    iptables -t mangle -A SHADOWSOCKS -p udp --dport 53 -j TPROXY --on-port 12345 --tproxy-mark 0x01/0x01

    # Apply the rules
    iptables -t nat -A PREROUTING -p tcp -j SHADOWSOCKS
    iptables -t mangle -A PREROUTING -j SHADOWSOCKS

    # Start the shadowsocks-redir
    ss-redir -u -c /etc/config/shadowsocks.json -f /var/run/shadowsocks.pid

## PROTOCOL

`ss-manager`(1) provides several APIs through UDP protocol
  Send UDP commands in the following format to the manager-address provided to ss-manager(1):

    command: [JSON data]

  To add a port:

    add: {"server_port": 8001, "password":"7cd308cc059"}

  To remove a port:

    remove: {"server_port": 8001}

  To receive a pong:

    ping

  Then `ss-manager`(1) will send back the traffic statistics:

    stat: {"8001":11370}

## SEE ALSO

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

Last updated 2021-12-28 18:01:25 UTC