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Shadowsocks-libev is a lightweight secured SOCKS5 proxy for embedded devices and low-end boxes.

It is a port of Shadowsocks created by @clowwindy, and maintained by @madeye and @linusyang.

Current version: 3.0.4 | Changelog

Travis CI: Travis CI


Shadowsocks-libev is written in pure C and depends on libev. It's designed to be a very simple implementation of shadowsocks protocol, in order to keep the resource usage as low as possible.

For a full list of feature comparison between different versions of shadowsocks, refer to the Wiki page.


Get the latest source code

To get the latest source code, you should also update the submodules as following:

git clone
cd shadowsocks-libev
git submodule update --init --recursive

Build and install with recent libsodium

You have to install libsodium 1.0.8 or later before building. See Directly build and install on UNIX-like system.


Distribution-specific guide

Pre-build configure guide

For a complete list of avaliable configure-time option, try configure --help.

Debian & Ubuntu

Install from repository

Note: The repositories doesn't always contain the latest version. Please build from source if you want the latest version. (see below)

Shadowsocks-libev is available in the official repository for following distributions:

  • Debian 9 or higher (including testing and unstable/sid)
  • Ubuntu 16.10 or higher
sudo apt update
sudo apt install shadowsocks-libev

For Debian 8 (Jessie) users, please install it from jessie-backports: We strongly encourage you to install shadowsocks-libev from jessie-backports. Please follow instructions on Debian Backports.

sudo sh -c 'printf "deb jessie-backports main" > /etc/apt/sources.list.d/jessie-backports.list'
sudo apt update
sudo apt -t jessie-backports install shadowsocks-libev

Build deb package from source

Supported distributions:

  • Debian 8, 9 or higher
  • Ubuntu 14.04 LTS, 16.04 LTS, 16.10 or higher

For older systems, building .deb packages is not supported. Please directly install it from source.

You can build shadowsocks-libev and all its dependencies by script:

mkdir -p ~/build-area/
cp ./scripts/ ~/build-area/
cd ~/build-area

Otherwise, try to build and install directly from source. See the Linux section below.

Note for Debian 8 (Jessie) users:

We strongly encourage you to install shadowsocks-libev from jessie-backports. If you insist on building from source, you will need to manually install libsodium from jessie-backports, NOT libsodium in main repository.

Please follow the instructions on Debian Backports Website.

cd shadowsocks-libev
sudo apt-get install --no-install-recommends devscripts equivs
mk-build-deps --root-cmd sudo --install --tool "apt-get -o Debug::pkgProblemResolver=yes --no-install-recommends -y"
./ && dpkg-buildpackage -b -us -uc
cd ..
sudo dpkg -i shadowsocks-libev*.deb

Configure and start the service

# Edit the configuration file
sudo vim /etc/shadowsocks-libev/config.json

# Edit the default configuration for debian
sudo vim /etc/default/shadowsocks-libev

# Start the service
sudo /etc/init.d/shadowsocks-libev start    # for sysvinit, or
sudo systemctl start shadowsocks-libev      # for systemd

Fedora & RHEL

Supported distributions:

  • Fedora 22, 23, 24
  • RHEL 6, 7 and derivatives (including CentOS, Scientific Linux)

Build from source with centos

If you are using CentOS 7, you need to install these prequirement to build from source code:

yum install epel-release -y
yum install gcc gettext autoconf libtool automake make pcre-devel asciidoc xmlto udns-devel libev-devel -y

Install from repository

Enable repo via dnf:

su -c 'dnf copr enable librehat/shadowsocks'

Or download yum repo on Fedora Copr and put it inside /etc/yum.repos.d/. The release Epel is for RHEL and its derivatives.

Then, install shadowsocks-libev via dnf:

su -c 'dnf update'
su -c 'dnf install shadowsocks-libev'

or yum:

su -c 'yum update'
su -c 'yum install shadowsocks-libev'


sudo pacman -S shadowsocks-libev

Please refer to downstream PKGBUILD script for extra modifications and distribution-specific bugs.


nix-env -iA nixos.shadowsocks-libev


nix-env -iA nixpkgs.shadowsocks-libev


In general, you need the following build dependencies:

  • autotools (autoconf, automake, libtool)
  • gettext
  • pkg-config
  • libmbedtls
  • libsodium
  • libpcre3 (old pcre library)
  • libev
  • libudns
  • asciidoc (for documentation only)
  • xmlto (for documentation only)

If your system is too old to provide libmbedtls and libsodium (later than v1.0.8), you will need to either install those libraries manually or upgrade your system.

If your system provides with those libraries, you should not install them from source. You should jump this section and install them from distribution repository instead.

For some of the distributions, you might install build dependencies like this:

# Installation of basic build dependencies
## Debian / Ubuntu
sudo apt-get install --no-install-recommends gettext build-essential autoconf libtool libpcre3-dev asciidoc xmlto libev-dev libudns-dev automake libmbedtls-dev libsodium-dev
## CentOS / Fedora / RHEL
sudo yum install gettext gcc autoconf libtool automake make asciidoc xmlto udns-devel libev-devel
## Arch
sudo pacman -S gettext gcc autoconf libtool automake make asciidoc xmlto udns libev

# Installation of Libsodium
export LIBSODIUM_VER=1.0.12
tar xvf libsodium-$LIBSODIUM_VER.tar.gz
pushd libsodium-$LIBSODIUM_VER
./configure --prefix=/usr && make
sudo make install
sudo ldconfig

# Installation of MbedTLS
export MBEDTLS_VER=2.4.2
tar xvf mbedtls-$MBEDTLS_VER-gpl.tgz
pushd mbedtls-$MBEDTLS_VER
sudo make DESTDIR=/usr install
sudo ldconfig

# Start building
./ && ./configure && make
sudo make install

You may need to manually install missing softwares.


cd /usr/ports/net/shadowsocks-libev
make install

Edit your config.json file. By default, it's located in /usr/local/etc/shadowsocks-libev.

To enable shadowsocks-libev, add the following rc variable to your /etc/rc.conf file:


Start the Shadowsocks server:

service shadowsocks_libev start


The OpenWRT project is maintained here: openwrt-shadowsocks.


For OS X, use Homebrew to install or build.

Install Homebrew:

ruby -e "$(curl -fsSL"

Install shadowsocks-libev:

brew install shadowsocks-libev


For a detailed and complete list of all supported arguments, you may refer to the man pages of the applications, respectively.


       -s <server_host>           host name or ip address of your remote server

       -p <server_port>           port number of your remote server

       -l <local_port>            port number of your local server

       -k <password>              password of your remote server

       -m <encrypt_method>        Encrypt method: rc4-md5,
                                  aes-128-gcm, aes-192-gcm, aes-256-gcm,
                                  aes-128-cfb, aes-192-cfb, aes-256-cfb,
                                  aes-128-ctr, aes-192-ctr, aes-256-ctr,
                                  camellia-128-cfb, camellia-192-cfb,
                                  camellia-256-cfb, bf-cfb,
                                  chacha20-poly1305, chacha20-ietf-poly1305
                                  salsa20, chacha20 and chacha20-ietf.

       [-f <pid_file>]            the file path to store pid

       [-t <timeout>]             socket timeout in seconds

       [-c <config_file>]         the path to config file

       [-i <interface>]           network interface to bind,
                                  not available in redir mode

       [-b <local_address>]       local address to bind,
                                  not available in server mode

       [-u]                       enable udprelay mode,
                                  TPROXY is required in redir mode

       [-U]                       enable UDP relay and disable TCP relay,
                                  not available in local 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,
                                  only available in server mode

       [--fast-open]              enable TCP fast open,
                                  only available in local and server mode,
                                  with Linux kernel > 3.7.0

       [--acl <acl_file>]         config file of ACL (Access Control List)
                                  only available in local and server mode

       [--manager-address <addr>] UNIX domain socket address
                                  only available in server and manager mode

       [--executable <path>]      path to the executable of ss-server
                                  only available in manager mode

       [--plugin <name>]          Enable SIP003 plugin. (Experimental)
       [--plugin-opts <options>]  Set SIP003 plugin options. (Experimental)

       [-v]                       verbose mode


    ss-redir provides a transparent proxy function and only works on the
    Linux platform with iptables.

Advanced usage

The latest shadowsocks-libev has provided a redir mode. You can configure your Linux-based box or router to proxy all TCP traffic transparently.

# Create new chain
root@Wrt:~# iptables -t nat -N SHADOWSOCKS
root@Wrt:~# iptables -t mangle -N SHADOWSOCKS
root@Wrt:~# iptables -t mangle -N SHADOWSOCKS_MARK

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

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

# Add any UDP rules
root@Wrt:~# ip route add local default dev lo table 100
root@Wrt:~# ip rule add fwmark 1 lookup 100
root@Wrt:~# iptables -t mangle -A SHADOWSOCKS -p udp --dport 53 -j TPROXY --on-port 12345 --tproxy-mark 0x01/0x01
root@Wrt:~# iptables -t mangle -A SHADOWSOCKS_MARK -p udp --dport 53 -j MARK --set-mark 1

# Apply the rules
root@Wrt:~# iptables -t nat -A OUTPUT -p tcp -j SHADOWSOCKS
root@Wrt:~# iptables -t mangle -A PREROUTING -j SHADOWSOCKS
root@Wrt:~# iptables -t mangle -A OUTPUT -j SHADOWSOCKS_MARK

# Start the shadowsocks-redir
root@Wrt:~# ss-redir -u -c /etc/config/shadowsocks.json -f /var/run/

Shadowsocks over KCP

It's quite easy to use shadowsocks and KCP together with kcptun.

The goal of shadowsocks over KCP is to provide a fully configurable, UDP based protocol to improve poor connections, e.g. a high packet loss 3G network.

Setup your server

server_linux_amd64 -l :21 -t --crypt none --mtu 1200 --nocomp --mode normal --dscp 46 &
ss-server -s -p 443 -k passwd -m chacha20 -u

Setup your client

client_linux_amd64 -l -r <server_ip>:21 --crypt none --mtu 1200 --nocomp --mode normal --dscp 46 &
ss-local -s -p 1090 -k passwd -m chacha20 -l 1080 -b &
ss-local -s <server_ip> -p 443 -k passwd -m chacha20 -l 1080 -U -b

Security Tips

Although shadowsocks-libev can handle thousands of concurrent connections nicely, we still recommend setting up your server's firewall rules to limit connections from each user:

# Up to 32 connections are enough for normal usage
iptables -A INPUT -p tcp --syn --dport ${SHADOWSOCKS_PORT} -m connlimit --connlimit-above 32 -j REJECT --reject-with tcp-reset


Copyright: 2013-2015, Clow Windy <>
           2013-2017, Max Lv <>
           2014, Linus Yang <>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <>.
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