#!/bin/sh # # Script for automatic setup of an IPsec VPN server on CentOS/RHEL 6 and 7. # Works on any dedicated server or virtual private server (VPS) except OpenVZ. # # DO NOT RUN THIS SCRIPT ON YOUR PC OR MAC! # # The latest version of this script is available at: # https://github.com/hwdsl2/setup-ipsec-vpn # # Copyright (C) 2015-2018 Lin Song # Based on the work of Thomas Sarlandie (Copyright 2012) # # This work is licensed under the Creative Commons Attribution-ShareAlike 3.0 # Unported License: http://creativecommons.org/licenses/by-sa/3.0/ # # Attribution required: please include my name in any derivative and let me # know how you have improved it! # ===================================================== # Define your own values for these variables # - IPsec pre-shared key, VPN username and password # - All values MUST be placed inside 'single quotes' # - DO NOT use these special characters within values: \ " ' YOUR_IPSEC_PSK='' YOUR_USERNAME='' YOUR_PASSWORD='' # Important notes: https://git.io/vpnnotes # Setup VPN clients: https://git.io/vpnclients # ===================================================== export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" SYS_DT="$(date +%F-%T)" exiterr() { echo "Error: $1" >&2; exit 1; } exiterr2() { exiterr "'yum install' failed."; } conf_bk() { /bin/cp -f "$1" "$1.old-$SYS_DT" 2>/dev/null; } bigecho() { echo; echo "## $1"; echo; } check_ip() { IP_REGEX='^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$' printf '%s' "$1" | tr -d '\n' | grep -Eq "$IP_REGEX" } vpnsetup() { if ! grep -qs -e "release 6" -e "release 7" /etc/redhat-release; then exiterr "This script only supports CentOS/RHEL 6 and 7." fi if [ -f /proc/user_beancounters ]; then exiterr "OpenVZ VPS is not supported. Try OpenVPN: github.com/Nyr/openvpn-install" fi if [ "$(id -u)" != 0 ]; then exiterr "Script must be run as root. Try 'sudo sh $0'" fi net_iface=${VPN_NET_IFACE:-'eth0'} def_iface="$(route 2>/dev/null | grep '^default' | grep -o '[^ ]*$')" [ -z "$def_iface" ] && def_iface="$(ip -4 route list 0/0 2>/dev/null | grep -Po '(?<=dev )(\S+)')" def_state=$(cat "/sys/class/net/$def_iface/operstate" 2>/dev/null) if [ -n "$def_state" ] && [ "$def_state" != "down" ]; then case "$def_iface" in wl*) exiterr "Wireless interface '$def_iface' detected. DO NOT run this script on your PC or Mac!" ;; esac net_iface="$def_iface" fi net_state=$(cat "/sys/class/net/$net_iface/operstate" 2>/dev/null) if [ -z "$net_state" ] || [ "$net_state" = "down" ] || [ "$net_iface" = "lo" ]; then printf "Error: Network interface '%s' is not available.\n" "$net_iface" >&2 if [ -z "$VPN_NET_IFACE" ]; then cat 1>&2 </dev/null && PREFIX=/usr make -s install cd /opt/src || exit 1 /bin/rm -rf "/opt/src/xl2tpd-$L2TP_VER" fi ;; esac bigecho "Installing Fail2Ban to protect SSH..." yum -y install fail2ban || exiterr2 bigecho "Compiling and installing Libreswan..." SWAN_VER=3.22 swan_file="libreswan-$SWAN_VER.tar.gz" swan_url1="https://github.com/libreswan/libreswan/archive/v$SWAN_VER.tar.gz" swan_url2="https://download.libreswan.org/$swan_file" if ! { wget -t 3 -T 30 -nv -O "$swan_file" "$swan_url1" || wget -t 3 -T 30 -nv -O "$swan_file" "$swan_url2"; }; then exit 1 fi /bin/rm -rf "/opt/src/libreswan-$SWAN_VER" tar xzf "$swan_file" && /bin/rm -f "$swan_file" cd "libreswan-$SWAN_VER" || exit 1 sed -i '/^#define LSWBUF_CANARY/s/-2$/((char) -2)/' include/lswlog.h cat > Makefile.inc.local <<'EOF' WERROR_CFLAGS = USE_DNSSEC = false EOF NPROCS="$(grep -c ^processor /proc/cpuinfo)" [ -z "$NPROCS" ] && NPROCS=1 make "-j$((NPROCS+1))" -s base && make -s install-base cd /opt/src || exit 1 /bin/rm -rf "/opt/src/libreswan-$SWAN_VER" if ! /usr/local/sbin/ipsec --version 2>/dev/null | grep -qF "$SWAN_VER"; then exiterr "Libreswan $SWAN_VER failed to build." fi bigecho "Creating VPN configuration..." L2TP_NET=${VPN_L2TP_NET:-'192.168.42.0/24'} L2TP_LOCAL=${VPN_L2TP_LOCAL:-'192.168.42.1'} L2TP_POOL=${VPN_L2TP_POOL:-'192.168.42.10-192.168.42.250'} XAUTH_NET=${VPN_XAUTH_NET:-'192.168.43.0/24'} XAUTH_POOL=${VPN_XAUTH_POOL:-'192.168.43.10-192.168.43.250'} DNS_SRV1=${VPN_DNS_SRV1:-'8.8.8.8'} DNS_SRV2=${VPN_DNS_SRV2:-'8.8.4.4'} # Create IPsec config conf_bk "/etc/ipsec.conf" cat > /etc/ipsec.conf </dev/null | grep -qs ' src '; then PRIVATE_IP=$(ip -4 route get 1 | sed 's/ uid .*//' | awk '{print $NF;exit}') check_ip "$PRIVATE_IP" && sed -i "s/left=%defaultroute/left=$PRIVATE_IP/" /etc/ipsec.conf fi # Specify IPsec PSK conf_bk "/etc/ipsec.secrets" cat > /etc/ipsec.secrets < /etc/xl2tpd/xl2tpd.conf < /etc/ppp/options.xl2tpd < /etc/ppp/chap-secrets < /etc/ipsec.d/passwd <> /etc/sysctl.conf </dev/null \ || ! iptables -t nat -C POSTROUTING -s "$XAUTH_NET" -o "$net_iface" -m policy --dir out --pol none -j MASQUERADE 2>/dev/null; then ipt_flag=1 fi # Add IPTables rules for VPN if [ "$ipt_flag" = "1" ]; then service fail2ban stop >/dev/null 2>&1 iptables-save > "$IPT_FILE.old-$SYS_DT" iptables -I INPUT 1 -p udp --dport 1701 -m policy --dir in --pol none -j DROP iptables -I INPUT 2 -m conntrack --ctstate INVALID -j DROP iptables -I INPUT 3 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT iptables -I INPUT 4 -p udp -m multiport --dports 500,4500 -j ACCEPT iptables -I INPUT 5 -p udp --dport 1701 -m policy --dir in --pol ipsec -j ACCEPT iptables -I INPUT 6 -p udp --dport 1701 -j DROP iptables -I FORWARD 1 -m conntrack --ctstate INVALID -j DROP iptables -I FORWARD 2 -i "$net_iface" -o ppp+ -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT iptables -I FORWARD 3 -i ppp+ -o "$net_iface" -j ACCEPT iptables -I FORWARD 4 -i ppp+ -o ppp+ -s "$L2TP_NET" -d "$L2TP_NET" -j ACCEPT iptables -I FORWARD 5 -i "$net_iface" -d "$XAUTH_NET" -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT iptables -I FORWARD 6 -s "$XAUTH_NET" -o "$net_iface" -j ACCEPT # Uncomment if you wish to disallow traffic between VPN clients themselves # iptables -I FORWARD 2 -i ppp+ -o ppp+ -s "$L2TP_NET" -d "$L2TP_NET" -j DROP # iptables -I FORWARD 3 -s "$XAUTH_NET" -d "$XAUTH_NET" -j DROP iptables -A FORWARD -j DROP iptables -t nat -I POSTROUTING -s "$XAUTH_NET" -o "$net_iface" -m policy --dir out --pol none -j MASQUERADE iptables -t nat -I POSTROUTING -s "$L2TP_NET" -o "$net_iface" -j MASQUERADE echo "# Modified by hwdsl2 VPN script" > "$IPT_FILE" iptables-save >> "$IPT_FILE" fi bigecho "Creating basic Fail2Ban rules..." if [ ! -f /etc/fail2ban/jail.local ] ; then cat > /etc/fail2ban/jail.local <<'EOF' [ssh-iptables] enabled = true filter = sshd action = iptables[name=SSH, port=ssh, protocol=tcp] logpath = /var/log/secure EOF fi bigecho "Enabling services on boot..." if grep -qs "release 6" /etc/redhat-release; then chkconfig iptables on chkconfig fail2ban on else systemctl --now mask firewalld 2>/dev/null systemctl enable iptables fail2ban 2>/dev/null fi if ! grep -qs "hwdsl2 VPN script" /etc/rc.local; then if [ -f /etc/rc.local ]; then conf_bk "/etc/rc.local" else echo '#!/bin/sh' > /etc/rc.local fi cat >> /etc/rc.local <<'EOF' # Added by hwdsl2 VPN script (sleep 15 modprobe -q pppol2tp service ipsec restart service xl2tpd restart echo 1 > /proc/sys/net/ipv4/ip_forward)& EOF fi bigecho "Starting services..." # Restore SELinux contexts restorecon /etc/ipsec.d/*db 2>/dev/null restorecon /usr/local/sbin -Rv 2>/dev/null restorecon /usr/local/libexec/ipsec -Rv 2>/dev/null # Reload sysctl.conf sysctl -e -q -p # Update file attributes chmod +x /etc/rc.local chmod 600 /etc/ipsec.secrets* /etc/ppp/chap-secrets* /etc/ipsec.d/passwd* # Apply new IPTables rules iptables-restore < "$IPT_FILE" # Fix xl2tpd on CentOS 7, if kernel module "l2tp_ppp" is unavailable if grep -qs "release 7" /etc/redhat-release; then if ! modprobe -q l2tp_ppp; then sed -i '/^ExecStartPre/s/^/#/' /usr/lib/systemd/system/xl2tpd.service systemctl daemon-reload fi fi # Restart services modprobe -q pppol2tp service fail2ban restart 2>/dev/null service ipsec restart 2>/dev/null service xl2tpd restart 2>/dev/null cat <