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- #!/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 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_iface_state=$(cat "/sys/class/net/$def_iface/operstate" 2>/dev/null)
- if [ -n "$def_iface_state" ] && [ "$def_iface_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="$def_iface"
- fi
- net_iface_state=$(cat "/sys/class/net/$net_iface/operstate" 2>/dev/null)
- if [ -z "$net_iface_state" ] || [ "$net_iface_state" = "down" ] || [ "$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 <<EOF
- Unable to detect the default network interface. Manually re-run this script with:
- sudo VPN_NET_IFACE="your_default_interface_name" 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 $VPN_PASSWORD" in
- *[\\\"\']*)
- exiterr "VPN credentials must not contain these special characters: \\ \" '"
- ;;
- esac
- bigecho "VPN setup in progress... Please be patient."
- # Create and change to working dir
- mkdir -p /opt/src
- cd /opt/src || exiterr "Cannot enter /opt/src."
- bigecho "Installing packages required for setup..."
- yum -y install wget bind-utils openssl \
- iproute gawk grep sed net-tools || exiterr2
- bigecho "Trying to auto discover IP of this server..."
- cat <<'EOF'
- In case the script hangs here for more than a few minutes,
- press Ctrl-C to abort. Then edit it and manually enter IP.
- EOF
- # In case auto IP discovery fails, enter server's public IP here.
- PUBLIC_IP=${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 "$PUBLIC_IP" || exiterr "Cannot detect this server's public IP. Edit the script and manually enter it."
- bigecho "Adding the EPEL repository..."
- epel_url="https://dl.fedoraproject.org/pub/epel/epel-release-latest-$(rpm -E '%{rhel}').noarch.rpm"
- yum -y install epel-release || yum -y install "$epel_url" || exiterr2
- bigecho "Installing packages required for the VPN..."
- yum -y install nss-devel nspr-devel pkgconfig pam-devel \
- libcap-ng-devel libselinux-devel curl-devel \
- flex bison gcc make ppp xl2tpd || exiterr2
- OPT1='--enablerepo=*server-optional*'
- OPT2='--enablerepo=*releases-optional*'
- if grep -qs "release 6" /etc/redhat-release; then
- yum -y remove libevent-devel
- yum "$OPT1" "$OPT2" -y install libevent2-devel fipscheck-devel || exiterr2
- else
- yum -y install systemd-devel iptables-services || exiterr2
- yum "$OPT1" "$OPT2" -y install libevent-devel fipscheck-devel || exiterr2
- fi
- bigecho "Installing Fail2Ban to protect SSH..."
- yum -y install fail2ban || exiterr2
- bigecho "Compiling and installing Libreswan..."
- SWAN_VER=3.23
- swan_file="libreswan-$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."
- sed -i '/docker-targets\.mk/d' Makefile
- 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
- modecfgdns="$DNS_SRV1, $DNS_SRV2"
- leftxauthserver=yes
- rightxauthclient=yes
- leftmodecfgserver=yes
- rightmodecfgclient=yes
- modecfgpull=yes
- xauthby=file
- ike-frag=yes
- ikev2=never
- cisco-unity=yes
- also=shared
- EOF
- # Specify IPsec PSK
- conf_bk "/etc/ipsec.secrets"
- cat > /etc/ipsec.secrets <<EOF
- %any %any : PSK "$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 $DNS_SRV2
- noccp
- auth
- mtu 1280
- mru 1280
- proxyarp
- lcp-echo-failure 4
- lcp-echo-interval 30
- connect-delay 5000
- EOF
- # Create VPN credentials
- conf_bk "/etc/ppp/chap-secrets"
- cat > /etc/ppp/chap-secrets <<EOF
- "$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"
- if [ "$(getconf LONG_BIT)" = "64" ]; then
- SHM_MAX=68719476736
- SHM_ALL=4294967296
- else
- SHM_MAX=4294967295
- SHM_ALL=268435456
- fi
- cat >> /etc/sysctl.conf <<EOF
- # Added by hwdsl2 VPN script
- kernel.msgmnb = 65536
- kernel.msgmax = 65536
- kernel.shmmax = $SHM_MAX
- kernel.shmall = $SHM_ALL
- net.ipv4.ip_forward = 1
- net.ipv4.conf.all.accept_source_route = 0
- net.ipv4.conf.all.accept_redirects = 0
- net.ipv4.conf.all.send_redirects = 0
- net.ipv4.conf.all.rp_filter = 0
- net.ipv4.conf.default.accept_source_route = 0
- net.ipv4.conf.default.accept_redirects = 0
- net.ipv4.conf.default.send_redirects = 0
- net.ipv4.conf.default.rp_filter = 0
- net.ipv4.conf.$net_iface.send_redirects = 0
- net.ipv4.conf.$net_iface.rp_filter = 0
- net.core.wmem_max = 12582912
- net.core.rmem_max = 12582912
- net.ipv4.tcp_rmem = 10240 87380 12582912
- net.ipv4.tcp_wmem = 10240 87380 12582912
- EOF
- fi
- bigecho "Updating IPTables rules..."
- # Check if IPTables rules need updating
- ipt_flag=0
- IPT_FILE="/etc/sysconfig/iptables"
- if ! grep -qs "hwdsl2 VPN script" "$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, 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 <<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: $VPN_PASSWORD
- Write these down. You'll need them to connect!
- Important notes: https://git.io/vpnnotes
- Setup VPN clients: https://git.io/vpnclients
- ================================================
- EOF
- }
- ## Defer setup until we have the complete script
- vpnsetup "$@"
- exit 0
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