最近需要穿透防火墙接入内部网络，因为成本和技术问题决定N2N进行内网穿透。
n2n现在网上有两个版本，V1和V2版，Ubuntu软件源中的版本是V1版，现在V1现在很久没有更新了，性能也比不上V2版，于是改用V2版。
下面是编译过程
首先获取源码：
git clone https://github.com/meyerd/n2n --depth=1
cd ./n2n/n2n_v2
mkdir build
cd build
cmake ../
make
sudo make install
N2N分为supernode中心节点和edge边界节点，我们现在一个需要一个有着公网ip的服务器架设中心节点，架设起来很方便输入下面命令：
supernode -l 19576
edge -c test -a 10.1.2.3 -k testtest -l test.com:12345 -r -b -m d8:6d:2a:13:6d:7f
虽然命令行也可以使用，但是不方便，我们可以通过启动脚本启动edge。
启动脚本：
#!/bin/sh
### BEGIN INIT INFO
# Provides: n2n
# Required-Start: $network $remote_fs $local_fs
# Required-Stop: $remote_fs $local_fs
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Start or stop the n2n VPN
# Description: This script controls the n2n VPN service.
# It is called from the boot, halt and reboot scripts.
# So far, only 1 PVN is supported by this script.
# More can be started via the command line.
### END INIT INFO
#
# Author: Rolf Leggewie <foss@rolf.leggewie.biz>
set -e
# PATH should only include /usr/* if it runs after the mountnfs.sh script
PATH=/usr/local/sbin:/sbin:/usr/sbin:/bin:/usr/bin
DESC='n2n P2P VPN'
NAME=n2n
DAEMON=/usr/local/sbin/edge
DAEMON_ARGS="" # Arguments to run the daemon with
#PIDFILE=/var/run/$NAME-edge.pid
SCRIPTNAME=/etc/init.d/$NAME
# Exit if the package is not installed
[ -x "$DAEMON" ] || exit 0
# Read configuration variable file if it is present
[ -r /etc/default/$NAME ] && . /etc/default/$NAME
# Check config
if [ -z "$N2N_EDGE_CONFIG_DONE" ]
then
echo "Warning: n2n VPN client is not configured, edit config file in /etc/default/$NAME." 1>&2
exit 0
fi
# Load the VERBOSE setting and other rcS variables
. /lib/init/vars.sh
. /lib/lsb/init-functions
## Make sure /var/run/n2n exists.
#if [ ! -e /var/run/$NAME ] ; then
# mkdir -p /var/run/$NAME
# chown proxy:proxy /var/run/$NAME
# chmod 755 /var/run/$NAME
#fi
# Function that starts the daemon/service
#
do_start()
{
if [ -r /sys/class/net/edge0 ]; then
echo edge node is already running.
exit 0
fi
# Return
# 0 if daemon has been started
# 1 if daemon was already running
# 2 if daemon could not be started
start-stop-daemon --start --quiet --user nobody --exec $DAEMON --test > /dev/null \
|| return 1
export N2N_KEY
start-stop-daemon --start --quiet --user nobody --exec $DAEMON -- \
-a $N2N_IP -c $N2N_COMMUNITY -l $N2N_SUPERNODE:$N2N_SUPERNODE_PORT \
-u $(id -u nobody) -g $(id -g nobody) $DAEMON_ARGS $N2N_DAEMON_OPTS \
|| return 2
}
#
# Function that stops the daemon/service
#
do_stop()
{
# Return
# 0 if daemon has been stopped
# 1 if daemon was already stopped
# 2 if daemon could not be stopped
# other if a failure occurred
start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --user nobody --exec $DAEMON
RETVAL="$?"
[ "$RETVAL" = 2 ] && return 2
# Wait for children to finish too if this is a daemon that forks
# and if the daemon is only ever run from this initscript.
# If the above conditions are not satisfied then add some other code
# that waits for the process to drop all resources that could be
# needed by services started subsequently. A last resort is to
# sleep for some time.
start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec $DAEMON
[ "$?" = 2 ] && return 2
# Many daemons don't delete their pidfiles when they exit.
rm -f $PIDFILE
return "$RETVAL"
}
#
# Function that sends a SIGHUP to the daemon/service
#
do_reload() {
#
# If the daemon can reload its configuration without
# restarting (for example, when it is sent a SIGHUP),
# then implement that here.
#
start-stop-daemon --stop --signal 1 --quiet --name $NAME
return 0
}
case "$1" in
start)
[ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC " "$NAME"
do_start
case "$?" in
0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
esac
;;
stop)
[ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
do_stop
case "$?" in
0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
esac
;;
status)
status_of_proc "$DAEMON" "$NAME" && exit 0 || exit $?
;;
#reload|force-reload)
#
# If do_reload() is not implemented then leave this commented out
# and leave 'force-reload' as an alias for 'restart'.
#
#log_daemon_msg "Reloading $DESC" "$NAME"
#do_reload
#log_end_msg $?
#;;
restart|force-reload)
#
# If the "reload" option is implemented then remove the
# 'force-reload' alias
#
log_daemon_msg "Restarting $DESC" "$NAME"
do_stop
case "$?" in
0|1)
do_start
case "$?" in
0) log_end_msg 0 ;;
1) log_end_msg 1 ;; # Old process is still running
*) log_end_msg 1 ;; # Failed to start
esac
;;
*)
# Failed to stop
log_end_msg 1
;;
esac
;;
*)
N=/etc/init.d/$NAME
#echo "Usage: $SCRIPTNAME {start|stop|restart|reload|force-reload}" >&2
echo "Usage: $SCRIPTNAME {start|stop|status|restart|force-reload}" >&2
exit 3
;;
esac
exit 0
# Config file for the n2n edge node daemon.
# Sets the n2n community name. All edges within the same community appear on
# the same LAN (layer 2 network segment). Community name is 16 bytes in length.
N2N_COMMUNITY="test_TEST"
# Sets the twofish encryption key from ASCII text. All edges communicating must
# use the same key and community name.
N2N_KEY="testtest"
# Sets the n2n supernode IP address and port to register to.
N2N_SUPERNODE="test.test.com"
N2N_SUPERNODE_PORT="12345"
# Sets the n2n virtual LAN IP address being claimed. This is a private IP
# address. All IP addresses in an n2n community typical belong to the same /24
# net‐ work (ie. only the last octet of the IP addresses varies).
N2N_IP="10.1.2.4"
N2N_DAEMON_OPTS="-b -r -m d8:6d:2a:13:6d:7f"
# Uncomment this to get edge node started.
N2N_EDGE_CONFIG_DONE="yes"
#TODO
# add routing option
# sudo ip route add 192.168.1.0/24 via 10.1.2.1
sudo systemctl daemon-reload
sudo systemctl restart n2n
sudo systemctl enable n2n
windows下面安装这个软件http://www.vpnhosting.cz/n2nguien.exe然后用下面我编译好的windows版edge替换掉安装目录里面的edge2然后在软件中填入相应信息就可以了。
ps:通过N2N连接到其它设备的网络中：
A设备网段为192.168.1.2，N2N的ip是10.1.2.1，B设备网段是192.168.2.2，N2N的IP是10.1.2.3，B设备开启ip转发，添加相应iptables规则：
echo "1" > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -s 10.1.2.0/24 -j MASQUERADE
sudo ip route add 192.168.2.0/24 via 10.1.2.3
现在A设备可以连接192.168.2.2网段了，不过通过N2N连接速度比较慢。
这里顺便附上在Linux下面编译windows客户端的方法。
首先安装交叉编译需要的依赖：
sudo apt install mingw-w64
SET(CMAKE_C_COMPILER x86_64-w64-mingw32-gcc)
SET(CMAKE_CXX_COMPILER x86_64-w64-mingw32-g++)
SET(CMAKE_RC_COMPILER x86_64-w64-mingw32-windres)
cmake -DCMAKE_TOOLCHAIN_FILE=../cmake/CMakeToolchainFileMingw32.cmake --build ./ ../
make
pss:这个是我编译好的N2N软件，包含Linux下面32位和64位的N2N_v2版和windows下面的N2N_v2版，大家可以直接下载使用，免去编译烦恼。