#!/bin/sh # # Script for automatic setup of an IPsec VPN server on CentOS/RHEL 6 & 7. # Works on dedicated servers and any KVM- or Xen-based Virtual Private Server (VPS). # # DO NOT RUN THIS SCRIPT ON YOUR PC OR MAC! THIS IS MEANT TO BE RUN # ON YOUR DEDICATED SERVER OR VPS! # # 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" exiterr() { echo "Error: ${1}" >&2; exit 1; } exiterr2() { echo "Error: 'yum install' failed." >&2; exit 1; } if [ ! -f /etc/redhat-release ]; then exiterr "This script only supports CentOS/RHEL." fi if ! grep -qs -e "release 6" -e "release 7" /etc/redhat-release; then exiterr "This script only supports CentOS/RHEL 6 and 7." fi if [ -f /proc/user_beancounters ]; then exiterr "This script does not support OpenVZ VPS." fi if [ "$(id -u)" != 0 ]; then exiterr "Script must be run as root. Try 'sudo sh $0'" fi eth0_state=$(cat /sys/class/net/eth0/operstate 2>/dev/null) if [ -z "$eth0_state" ] || [ "$eth0_state" = "down" ]; then cat 1>&2 <<'EOF' Error: Network interface 'eth0' is not available. Run 'cat /proc/net/dev' to find the active network interface, then use it to replace ALL 'eth0' and 'eth+' in this script. 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 cat <<'EOF' VPN setup in progress... Please be patient. EOF # 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:-''} # In Amazon EC2, these two variables will be retrieved from metadata [ -z "$PUBLIC_IP" ] && PUBLIC_IP=$(wget -t 3 -T 15 -qO- 'http://169.254.169.254/latest/meta-data/public-ipv4') [ -z "$PRIVATE_IP" ] && PRIVATE_IP=$(wget -t 3 -T 15 -qO- 'http://169.254.169.254/latest/meta-data/local-ipv4') # Try to find IPs for non-EC2 servers [ -z "$PUBLIC_IP" ] && PUBLIC_IP=$(dig @resolver1.opendns.com -t A -4 myip.opendns.com +short) [ -z "$PUBLIC_IP" ] && PUBLIC_IP=$(wget -t 3 -T 15 -qO- http://whatismyip.akamai.com) [ -z "$PUBLIC_IP" ] && PUBLIC_IP=$(wget -t 3 -T 15 -qO- http://ipv4.icanhazip.com) [ -z "$PRIVATE_IP" ] && PRIVATE_IP=$(ip -4 route get 1 | awk '{print $NF;exit}') [ -z "$PRIVATE_IP" ] && PRIVATE_IP=$(ifconfig eth0 | grep -Eo 'inet (addr:)?([0-9]*\.){3}[0-9]*' | grep -Eo '([0-9]*\.){3}[0-9]*') # Check IPs for correct format IP_REGEX="^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$" if ! printf %s "$PUBLIC_IP" | grep -Eq "$IP_REGEX"; then exiterr "Cannot find valid public IP. Edit the script and manually enter IPs." fi if ! printf %s "$PRIVATE_IP" | grep -Eq "$IP_REGEX"; then exiterr "Cannot find valid private IP. Edit the script and manually enter IPs." fi # 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 yum -y install fail2ban || exiterr2 # Install libevent2 and systemd-devel (CentOS 7) if grep -qs "release 6" /etc/redhat-release; then yum -y remove libevent-devel yum -y install libevent2-devel || exiterr2 elif grep -qs "release 7" /etc/redhat-release; then yum -y install libevent-devel systemd-devel || exiterr2 fi # Compile and install Libreswan swan_ver=3.17 swan_file="libreswan-${swan_ver}.tar.gz" swan_url1="https://download.libreswan.org/$swan_file" swan_url2="https://github.com/libreswan/libreswan/archive/v${swan_ver}.tar.gz" wget -t 3 -T 30 -nv -O "$swan_file" "$swan_url1" || wget -t 3 -T 30 -nv -O "$swan_file" "$swan_url2" [ "$?" != "0" ] && exiterr "Cannot download Libreswan source." /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-$swan_ver" /usr/local/sbin/ipsec --version 2>/dev/null | grep -qs "$swan_ver" [ "$?" != "0" ] && exiterr "Libreswan $swan_ver failed to build." # Create IPsec (Libreswan) config sys_dt="$(date +%Y-%m-%d-%H:%M:%S)" /bin/cp -f /etc/ipsec.conf "/etc/ipsec.conf.old-$sys_dt" 2>/dev/null cat > /etc/ipsec.conf </dev/null cat > /etc/ipsec.secrets </dev/null cat > /etc/xl2tpd/xl2tpd.conf <<'EOF' [global] port = 1701 [lns default] ip range = 192.168.42.10-192.168.42.250 local ip = 192.168.42.1 require chap = yes refuse pap = yes require authentication = yes name = l2tpd pppoptfile = /etc/ppp/options.xl2tpd length bit = yes EOF # Set xl2tpd options /bin/cp -f /etc/ppp/options.xl2tpd "/etc/ppp/options.xl2tpd.old-$sys_dt" 2>/dev/null 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 /bin/cp -f /etc/ppp/chap-secrets "/etc/ppp/chap-secrets.old-$sys_dt" 2>/dev/null cat > /etc/ppp/chap-secrets </dev/null VPN_PASSWORD_ENC=$(openssl passwd -1 "$VPN_PASSWORD") cat > /etc/ipsec.d/passwd </dev/null cat >> /etc/sysctl.conf <<'EOF' # Added by hwdsl2 VPN script kernel.msgmnb = 65536 kernel.msgmax = 65536 kernel.shmmax = 68719476736 kernel.shmall = 4294967296 net.ipv4.ip_forward = 1 net.ipv4.tcp_syncookies = 1 net.ipv4.conf.all.accept_source_route = 0 net.ipv4.conf.default.accept_source_route = 0 net.ipv4.conf.all.accept_redirects = 0 net.ipv4.conf.default.accept_redirects = 0 net.ipv4.conf.all.send_redirects = 0 net.ipv4.conf.default.send_redirects = 0 net.ipv4.conf.lo.send_redirects = 0 net.ipv4.conf.eth0.send_redirects = 0 net.ipv4.conf.all.rp_filter = 0 net.ipv4.conf.default.rp_filter = 0 net.ipv4.conf.lo.rp_filter = 0 net.ipv4.conf.eth0.rp_filter = 0 net.ipv4.icmp_echo_ignore_broadcasts = 1 net.ipv4.icmp_ignore_bogus_error_responses = 1 net.core.wmem_max = 12582912 net.core.rmem_max = 12582912 net.ipv4.tcp_rmem = 10240 87380 12582912 net.ipv4.tcp_wmem = 10240 87380 12582912 EOF fi # Create basic IPTables rules. First check for existing rules. # - If IPTables is "empty", simply write out the new rules. # - If *not* empty, insert new rules and save them with existing ones. if ! grep -qs "hwdsl2 VPN script" /etc/sysconfig/iptables; then service fail2ban stop >/dev/null 2>&1 if [ "$(iptables-save | grep -c '^\-')" = "0" ]; then cat > /etc/sysconfig/iptables < "/etc/sysconfig/iptables.old-$sys_dt" iptables -I INPUT 1 -p udp -m multiport --dports 500,4500 -j ACCEPT iptables -I INPUT 2 -p udp --dport 1701 -m policy --dir in --pol ipsec -j ACCEPT iptables -I INPUT 3 -p udp --dport 1701 -j DROP iptables -I FORWARD 1 -m conntrack --ctstate INVALID -j DROP iptables -I FORWARD 2 -i eth+ -o ppp+ -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT iptables -I FORWARD 3 -i ppp+ -o eth+ -j ACCEPT iptables -I FORWARD 4 -i ppp+ -o ppp+ -s 192.168.42.0/24 -d 192.168.42.0/24 -j ACCEPT iptables -I FORWARD 5 -i eth+ -d 192.168.43.0/24 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT iptables -I FORWARD 6 -s 192.168.43.0/24 -o eth+ -j ACCEPT # Uncomment to DROP traffic between VPN clients themselves # iptables -I FORWARD 2 -i ppp+ -o ppp+ -s 192.168.42.0/24 -d 192.168.42.0/24 -j DROP # iptables -I FORWARD 3 -s 192.168.43.0/24 -d 192.168.43.0/24 -j DROP iptables -A FORWARD -j DROP iptables -t nat -I POSTROUTING -s 192.168.43.0/24 -o eth+ -m policy --dir out --pol none -j SNAT --to-source "$PRIVATE_IP" iptables -t nat -I POSTROUTING -s 192.168.42.0/24 -o eth+ -j SNAT --to-source "$PRIVATE_IP" echo "# Modified by hwdsl2 VPN script" > /etc/sysconfig/iptables iptables-save >> /etc/sysconfig/iptables fi fi # Create basic Fail2Ban rules if [ ! -f /etc/fail2ban/jail.local ] ; then cat > /etc/fail2ban/jail.local <<'EOF' [DEFAULT] ignoreip = 127.0.0.1/8 bantime = 600 findtime = 600 maxretry = 5 backend = auto [ssh-iptables] enabled = true filter = sshd action = iptables[name=SSH, port=ssh, protocol=tcp] logpath = /var/log/secure EOF fi # Start services at boot if ! grep -qs "hwdsl2 VPN script" /etc/rc.local; then /bin/cp -f /etc/rc.local "/etc/rc.local.old-$sys_dt" 2>/dev/null cat >> /etc/rc.local <<'EOF' # Added by hwdsl2 VPN script iptables-restore < /etc/sysconfig/iptables service fail2ban restart 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 < /etc/sysconfig/iptables # Restart services service fail2ban stop >/dev/null 2>&1 service ipsec stop >/dev/null 2>&1 service xl2tpd stop >/dev/null 2>&1 service fail2ban start service ipsec start service xl2tpd start cat <