#!/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) 2015-2016 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 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 +%Y-%m-%d-%H:%M:%S)"; export SYS_DT exiterr() { echo "Error: ${1}" >&2; exit 1; } exiterr2() { echo "Error: 'yum install' failed." >&2; exit 1; } conf_bk() { /bin/cp -f "${1}" "${1}.old-$SYS_DT" 2>/dev/null; } 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 "$IP_REGEX" } if [ ! -f /etc/redhat-release ]; then exiterr "This script only supports CentOS/RHEL." fi if ! grep -qs -e "release 6" -e "release 7" /etc/redhat-release; then exiterr "This script only supports CentOS/RHEL 6 and 7." fi if [ -f /proc/user_beancounters ]; then exiterr "This script does not support OpenVZ VPS." fi if [ "$(id -u)" != 0 ]; then exiterr "Script must be run as root. Try 'sudo sh $0'" fi NET_IF0=${VPN_IFACE:-'eth0'} NET_IFS=${VPN_IFACE:-'eth+'} if_state=$(cat "/sys/class/net/$NET_IF0/operstate" 2>/dev/null) if [ -z "$if_state" ] || [ "$if_state" = "down" ] || [ "$NET_IF0" = "lo" ]; then echo "Error: Network interface '$NET_IF0' is not available." >&2 cat 1>&2 <<'EOF' DO NOT RUN THIS SCRIPT ON YOUR PC OR MAC! If running on a server, you may fix this error by first finding the active network interface: route | grep '^default' | grep -o '[^ ]*$' Then set this variable and re-run the script: export VPN_IFACE="YOUR_INTERFACE" EOF exit 1 fi [ -n "$YOUR_IPSEC_PSK" ] && VPN_IPSEC_PSK="$YOUR_IPSEC_PSK" [ -n "$YOUR_USERNAME" ] && VPN_USER="$YOUR_USERNAME" [ -n "$YOUR_PASSWORD" ] && VPN_PASSWORD="$YOUR_PASSWORD" if [ -z "$VPN_IPSEC_PSK" ] && [ -z "$VPN_USER" ] && [ -z "$VPN_PASSWORD" ]; then echo "VPN credentials not set by user. Generating random PSK and password..." echo VPN_IPSEC_PSK="$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 16)" VPN_USER=vpnuser VPN_PASSWORD="$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 16)" fi if [ -z "$VPN_IPSEC_PSK" ] || [ -z "$VPN_USER" ] || [ -z "$VPN_PASSWORD" ]; then exiterr "All VPN credentials must be specified. Edit the script and re-enter them." fi case "$VPN_IPSEC_PSK $VPN_USER $VPN_PASSWORD" in *[\\\"\']*) exiterr "VPN credentials must not contain any of these characters: \\ \" '" ;; esac echo "VPN setup in progress... Please be patient." echo # Create and change to working dir mkdir -p /opt/src cd /opt/src || exiterr "Cannot enter /opt/src." # Make sure basic commands exist yum -y install wget bind-utils openssl || exiterr2 yum -y install iproute gawk grep sed net-tools || exiterr2 cat <<'EOF' Trying to auto discover IPs of this server... In case the script hangs here for more than a few minutes, use Ctrl-C to interrupt. Then edit it and manually enter IPs. EOF # In case auto IP discovery fails, you may manually enter server IPs here. # If your server only has a public IP, put that public IP on both lines. PUBLIC_IP=${VPN_PUBLIC_IP:-''} PRIVATE_IP=${VPN_PRIVATE_IP:-''} # Try to auto discover IPs of this server [ -z "$PUBLIC_IP" ] && PUBLIC_IP=$(dig @resolver1.opendns.com -t A -4 myip.opendns.com +short) [ -z "$PRIVATE_IP" ] && PRIVATE_IP=$(ip -4 route get 1 | awk '{print $NF;exit}') # Check IPs for correct format check_ip "$PUBLIC_IP" || PUBLIC_IP=$(wget -t 3 -T 15 -qO- http://ipv4.icanhazip.com) check_ip "$PUBLIC_IP" || exiterr "Cannot find valid public IP. Edit the script and manually enter IPs." check_ip "$PRIVATE_IP" || PRIVATE_IP=$(ifconfig "$NET_IF0" | grep -Eo 'inet (addr:)?([0-9]*\.){3}[0-9]*' | grep -Eo '([0-9]*\.){3}[0-9]*') check_ip "$PRIVATE_IP" || exiterr "Cannot find valid private IP. Edit the script and manually enter IPs." # Add the EPEL repository yum -y install epel-release || exiterr2 # Install necessary packages yum -y install nss-devel nspr-devel pkgconfig pam-devel \ libcap-ng-devel libselinux-devel \ curl-devel flex bison gcc make \ fipscheck-devel unbound-devel xmlto || exiterr2 yum -y install ppp xl2tpd || exiterr2 # Install Fail2Ban to protect SSH server yum -y install fail2ban || exiterr2 # Install libevent2 and systemd-devel if grep -qs "release 6" /etc/redhat-release; then yum -y remove libevent-devel yum -y install libevent2-devel || exiterr2 else yum -y install libevent-devel systemd-devel || exiterr2 fi # Compile and install Libreswan swan_ver=3.18 swan_file="libreswan-$swan_ver.tar.gz" swan_url1="https://download.libreswan.org/$swan_file" swan_url2="https://github.com/libreswan/libreswan/archive/v$swan_ver.tar.gz" if ! { wget -t 3 -T 30 -nv -O "$swan_file" "$swan_url1" || wget -t 3 -T 30 -nv -O "$swan_file" "$swan_url2"; }; then exiterr "Cannot download Libreswan source." fi /bin/rm -rf "/opt/src/libreswan-$swan_ver" tar xzf "$swan_file" && /bin/rm -f "$swan_file" cd "libreswan-$swan_ver" || exiterr "Cannot enter Libreswan source dir." echo "WERROR_CFLAGS =" > Makefile.inc.local make -s programs && make -s install # Verify the install and clean up cd /opt/src || exiterr "Cannot enter /opt/src." /bin/rm -rf "/opt/src/libreswan-$swan_ver" if ! /usr/local/sbin/ipsec --version 2>/dev/null | grep -qs "$swan_ver"; then exiterr "Libreswan $swan_ver failed to build." fi # Create IPsec (Libreswan) config conf_bk "/etc/ipsec.conf" cat > /etc/ipsec.conf < /etc/ipsec.secrets < /etc/xl2tpd/xl2tpd.conf <<'EOF' [global] port = 1701 [lns default] ip range = 192.168.42.10-192.168.42.250 local ip = 192.168.42.1 require chap = yes refuse pap = yes require authentication = yes name = l2tpd pppoptfile = /etc/ppp/options.xl2tpd length bit = yes EOF # Set xl2tpd options conf_bk "/etc/ppp/options.xl2tpd" cat > /etc/ppp/options.xl2tpd <<'EOF' ipcp-accept-local ipcp-accept-remote ms-dns 8.8.8.8 ms-dns 8.8.4.4 noccp auth crtscts mtu 1280 mru 1280 lock proxyarp lcp-echo-failure 4 lcp-echo-interval 30 connect-delay 5000 EOF # Create VPN credentials conf_bk "/etc/ppp/chap-secrets" cat > /etc/ppp/chap-secrets < /etc/ipsec.d/passwd <> /etc/sysctl.conf </dev/null || \ ! iptables -t nat -C POSTROUTING -s 192.168.43.0/24 -o "$NET_IFS" -m policy --dir out --pol none -j SNAT --to-source "$PRIVATE_IP" 2>/dev/null; then ipt_flag=1 fi # Add IPTables rules for VPN if [ "$ipt_flag" = "1" ]; then service fail2ban stop >/dev/null 2>&1 iptables-save > "$IPT_FILE.old-$SYS_DT" iptables -I INPUT 1 -m conntrack --ctstate INVALID -j DROP iptables -I INPUT 2 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT iptables -I INPUT 3 -p udp -m multiport --dports 500,4500 -j ACCEPT iptables -I INPUT 4 -p udp --dport 1701 -m policy --dir in --pol ipsec -j ACCEPT iptables -I INPUT 5 -p udp --dport 1701 -j DROP iptables -I FORWARD 1 -m conntrack --ctstate INVALID -j DROP iptables -I FORWARD 2 -i "$NET_IFS" -o ppp+ -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT iptables -I FORWARD 3 -i ppp+ -o "$NET_IFS" -j ACCEPT iptables -I FORWARD 4 -i ppp+ -o ppp+ -s 192.168.42.0/24 -d 192.168.42.0/24 -j ACCEPT iptables -I FORWARD 5 -i "$NET_IFS" -d 192.168.43.0/24 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT iptables -I FORWARD 6 -s 192.168.43.0/24 -o "$NET_IFS" -j ACCEPT # Uncomment if you wish to disallow traffic between VPN clients themselves # iptables -I FORWARD 2 -i ppp+ -o ppp+ -s 192.168.42.0/24 -d 192.168.42.0/24 -j DROP # iptables -I FORWARD 3 -s 192.168.43.0/24 -d 192.168.43.0/24 -j DROP iptables -A FORWARD -j DROP iptables -t nat -I POSTROUTING -s 192.168.43.0/24 -o "$NET_IFS" -m policy --dir out --pol none -j SNAT --to-source "$PRIVATE_IP" iptables -t nat -I POSTROUTING -s 192.168.42.0/24 -o "$NET_IFS" -j SNAT --to-source "$PRIVATE_IP" echo "# Modified by hwdsl2 VPN script" > "$IPT_FILE" iptables-save >> "$IPT_FILE" fi # Create 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 # Start services at boot if grep -qs "release 6" /etc/redhat-release; then chkconfig iptables on chkconfig fail2ban on else systemctl --now mask firewalld yum -y install iptables-services || exiterr2 systemctl enable iptables fail2ban fi if ! grep -qs "hwdsl2 VPN script" /etc/rc.local; then conf_bk "/etc/rc.local" cat >> /etc/rc.local <<'EOF' # Added by hwdsl2 VPN script service ipsec start service xl2tpd start echo 1 > /proc/sys/net/ipv4/ip_forward EOF fi # 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" # Restart services service fail2ban restart 2>/dev/null service ipsec restart 2>/dev/null service xl2tpd restart 2>/dev/null cat <