#!/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) 2015-2017 Lin Song <linsongui@gmail.com> # 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; } 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" } 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 echo "Error: This script does not support OpenVZ VPS." >&2 echo "Try OpenVPN: https://github.com/Nyr/openvpn-install" >&2 exit 1 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+)')" if_state1=$(cat "/sys/class/net/$DEF_IFACE/operstate" 2>/dev/null) if [ -z "$VPN_NET_IFACE" ] && [ -n "$if_state1" ] && [ "$if_state1" != "down" ]; then if ! grep -qs raspbian /etc/os-release; then case "$DEF_IFACE" in wl*) cat 1>&2 <<EOF Error: Default network interface '$DEF_IFACE' detected. >> DO NOT RUN THIS SCRIPT ON YOUR PC OR MAC! << If you are certain that this script is running on a server, re-run it with: sudo VPN_NET_IFACE="$DEF_IFACE" sh "$0" EOF exit 1 ;; esac fi NET_IFACE="$DEF_IFACE" fi if_state2=$(cat "/sys/class/net/$NET_IFACE/operstate" 2>/dev/null) if [ -z "$if_state2" ] || [ "$if_state2" = "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 <<EOF Unable to detect your server's default network interface. You may manually re-run this script with: sudo VPN_NET_IFACE="your_default_network_interface" sh "$0" EOF fi exit 1 fi [ -n "$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 bigecho "VPN credentials not set by user. Generating random PSK and password..." 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 "$VPN_PASSWORD" ]; then exiterr "All VPN credentials must be specified. Edit the script and re-enter them." fi if printf %s "$VPN_IPSEC_PSK $VPN_USER $VPN_PASSWORD" | LC_ALL=C grep -q '[^ -~]\+'; then exiterr "VPN credentials must not contain non-ASCII characters." fi case "$VPN_IPSEC_PSK $VPN_USER $VPN_PASSWORD" in *[\\\"\']*) exiterr "VPN credentials must not contain the following characters: \\ \" '" ;; esac bigecho "VPN setup in progress... Please be patient." # Create and change to working dir mkdir -p /opt/src cd /opt/src || exiterr "Cannot enter /opt/src." bigecho "Installing packages required for setup..." yum -y install wget bind-utils openssl || exiterr2 yum -y install iproute gawk grep sed net-tools || exiterr2 bigecho "Trying to auto discover IP of this server..." cat <<'EOF' In case the script hangs here for more than a few minutes, use Ctrl-C to interrupt. Then edit it and manually enter IP. EOF # In case auto IP discovery fails, enter server's public IP here. PUBLIC_IP=${VPN_PUBLIC_IP:-''} # Try to auto discover IP of this server [ -z "$PUBLIC_IP" ] && PUBLIC_IP=$(dig @resolver1.opendns.com -t A -4 myip.opendns.com +short) # Check IP for correct format check_ip "$PUBLIC_IP" || PUBLIC_IP=$(wget -t 3 -T 15 -qO- http://ipv4.icanhazip.com) check_ip "$PUBLIC_IP" || exiterr "Cannot find valid public IP. Edit the script and manually enter it." bigecho "Adding the EPEL repository..." yum -y install epel-release || exiterr2 bigecho "Installing packages required for the VPN..." yum -y install nss-devel nspr-devel pkgconfig pam-devel \ libcap-ng-devel libselinux-devel \ curl-devel flex bison gcc make \ fipscheck-devel || exiterr2 yum -y install ppp xl2tpd || exiterr2 if grep -qs "release 6" /etc/redhat-release; then yum -y remove libevent-devel yum -y install libevent2-devel || exiterr2 else yum -y install libevent-devel systemd-devel || exiterr2 yum -y install iptables-services || exiterr2 fi bigecho "Installing Fail2Ban to protect SSH..." yum -y install fail2ban || exiterr2 bigecho "Compiling and installing Libreswan..." swan_ver=3.22 swan_file="libreswan-$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 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." cat > Makefile.inc.local <<'EOF' WERROR_CFLAGS = USE_DNSSEC = false EOF NPROCS="$(grep -c ^processor /proc/cpuinfo)" [ -z "$NPROCS" ] && NPROCS=1 make "-j$((NPROCS+1))" -s base && make -s install-base # Verify the install and clean up cd /opt/src || exiterr "Cannot enter /opt/src." /bin/rm -rf "/opt/src/libreswan-$swan_ver" if ! /usr/local/sbin/ipsec --version 2>/dev/null | grep -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 (Libreswan) config conf_bk "/etc/ipsec.conf" cat > /etc/ipsec.conf <<EOF version 2.0 config setup virtual-private=%v4:10.0.0.0/8,%v4:192.168.0.0/16,%v4:172.16.0.0/12,%v4:!$L2TP_NET,%v4:!$XAUTH_NET protostack=netkey interfaces=%defaultroute uniqueids=no conn shared left=%defaultroute leftid=$PUBLIC_IP right=%any encapsulation=yes authby=secret pfs=no rekey=no keyingtries=5 dpddelay=30 dpdtimeout=120 dpdaction=clear ike=3des-sha1,3des-sha2,aes-sha1,aes-sha1;modp1024,aes-sha2,aes-sha2;modp1024,aes256-sha2_512 phase2alg=3des-sha1,3des-sha2,aes-sha1,aes-sha2,aes256-sha2_512 sha2-truncbug=yes conn l2tp-psk auto=add leftprotoport=17/1701 rightprotoport=17/%any type=transport phase2=esp also=shared conn xauth-psk auto=add leftsubnet=0.0.0.0/0 rightaddresspool=$XAUTH_POOL modecfgdns1=$DNS_SRV1 modecfgdns2=$DNS_SRV2 leftxauthserver=yes rightxauthclient=yes leftmodecfgserver=yes rightmodecfgclient=yes modecfgpull=yes xauthby=file ike-frag=yes ikev2=never cisco-unity=yes also=shared EOF # Specify IPsec PSK conf_bk "/etc/ipsec.secrets" cat > /etc/ipsec.secrets <<EOF %any %any : PSK "$VPN_IPSEC_PSK" EOF # Create xl2tpd config conf_bk "/etc/xl2tpd/xl2tpd.conf" cat > /etc/xl2tpd/xl2tpd.conf <<EOF [global] port = 1701 [lns default] ip range = $L2TP_POOL local ip = $L2TP_LOCAL 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 +mschap-v2 ipcp-accept-local ipcp-accept-remote ms-dns $DNS_SRV1 ms-dns $DNS_SRV2 noccp auth mtu 1280 mru 1280 proxyarp lcp-echo-failure 4 lcp-echo-interval 30 connect-delay 5000 EOF # Create VPN credentials conf_bk "/etc/ppp/chap-secrets" cat > /etc/ppp/chap-secrets <<EOF # Secrets for authentication using CHAP # client server secret IP addresses "$VPN_USER" l2tpd "$VPN_PASSWORD" * EOF conf_bk "/etc/ipsec.d/passwd" VPN_PASSWORD_ENC=$(openssl passwd -1 "$VPN_PASSWORD") cat > /etc/ipsec.d/passwd <<EOF $VPN_USER:$VPN_PASSWORD_ENC:xauth-psk EOF bigecho "Updating sysctl settings..." if ! grep -qs "hwdsl2 VPN script" /etc/sysctl.conf; then conf_bk "/etc/sysctl.conf" 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.$NET_IFACE.send_redirects = 0 net.ipv4.conf.all.rp_filter = 0 net.ipv4.conf.default.rp_filter = 0 net.ipv4.conf.lo.rp_filter = 0 net.ipv4.conf.$NET_IFACE.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 bigecho "Updating IPTables rules..." # Check if IPTables rules need updating ipt_flag=0 IPT_FILE="/etc/sysconfig/iptables" if ! grep -qs "hwdsl2 VPN script" "$IPT_FILE" \ || ! iptables -t nat -C POSTROUTING -s "$L2TP_NET" -o "$NET_IFACE" -j MASQUERADE 2>/dev/null \ || ! iptables -t nat -C POSTROUTING -s "$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 for providers such as Linode, # where 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 <<EOF ================================================ IPsec VPN server is now ready for use! Connect to your new VPN with these details: Server IP: $PUBLIC_IP IPsec PSK: $VPN_IPSEC_PSK Username: $VPN_USER Password: $VPN_PASSWORD Write these down. You'll need them to connect! Important notes: https://git.io/vpnnotes Setup VPN clients: https://git.io/vpnclients ================================================ EOF exit 0