2b6586cf1b
- Set both "ikelifetime" and "salifetime" to 24 hours, which is recommended since we have "rekey=no" on the server. VPN clients will normally initiate rekey with a shorter interval. Ref: https://github.com/libreswan/libreswan/issues/405#issuecomment-765109809 https://libreswan.org/man/ipsec.conf.5.html
473 lines
14 KiB
Bash
473 lines
14 KiB
Bash
#!/bin/sh
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#
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# Script for automatic setup of an IPsec VPN server on Amazon Linux 2
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# Works on any dedicated server or virtual private server (VPS)
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#
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# DO NOT RUN THIS SCRIPT ON YOUR PC OR MAC!
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#
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# The latest version of this script is available at:
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# https://github.com/hwdsl2/setup-ipsec-vpn
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#
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# Copyright (C) 2020-2021 Lin Song <linsongui@gmail.com>
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#
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# This work is licensed under the Creative Commons Attribution-ShareAlike 3.0
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# Unported License: http://creativecommons.org/licenses/by-sa/3.0/
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#
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# Attribution required: please include my name in any derivative and let me
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# know how you have improved it!
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# =====================================================
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# Define your own values for these variables
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# - IPsec pre-shared key, VPN username and password
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# - All values MUST be placed inside 'single quotes'
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# - DO NOT use these special characters within values: \ " '
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YOUR_IPSEC_PSK=''
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YOUR_USERNAME=''
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YOUR_PASSWORD=''
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# Important notes: https://git.io/vpnnotes
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# Setup VPN clients: https://git.io/vpnclients
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# IKEv2 guide: https://git.io/ikev2
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# =====================================================
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export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
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SYS_DT=$(date +%F-%T | tr ':' '_')
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exiterr() { echo "Error: $1" >&2; exit 1; }
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exiterr2() { exiterr "'yum install' failed."; }
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conf_bk() { /bin/cp -f "$1" "$1.old-$SYS_DT" 2>/dev/null; }
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bigecho() { echo; echo "## $1"; echo; }
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check_ip() {
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IP_REGEX='^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$'
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printf '%s' "$1" | tr -d '\n' | grep -Eq "$IP_REGEX"
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}
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vpnsetup() {
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os_arch=$(uname -m | tr -dc 'A-Za-z0-9_-')
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if ! grep -qs "Amazon Linux release 2" /etc/system-release; then
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echo "Error: This script only supports Amazon Linux 2." >&2
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echo "For Ubuntu/Debian, use https://git.io/vpnsetup" >&2
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echo "For CentOS/RHEL, use https://git.io/vpnsetup-centos" >&2
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exit 1
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fi
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if [ "$(id -u)" != 0 ]; then
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exiterr "Script must be run as root. Try 'sudo sh $0'"
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fi
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def_iface=$(route 2>/dev/null | grep -m 1 '^default' | grep -o '[^ ]*$')
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[ -z "$def_iface" ] && def_iface=$(ip -4 route list 0/0 2>/dev/null | grep -m 1 -Po '(?<=dev )(\S+)')
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def_state=$(cat "/sys/class/net/$def_iface/operstate" 2>/dev/null)
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if [ -n "$def_state" ] && [ "$def_state" != "down" ]; then
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case $def_iface in
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wl*)
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exiterr "Wireless interface '$def_iface' detected. DO NOT run this script on your PC or Mac!"
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;;
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esac
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NET_IFACE="$def_iface"
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else
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eth0_state=$(cat "/sys/class/net/eth0/operstate" 2>/dev/null)
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if [ -z "$eth0_state" ] || [ "$eth0_state" = "down" ]; then
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exiterr "Could not detect the default network interface."
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fi
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NET_IFACE=eth0
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fi
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[ -n "$YOUR_IPSEC_PSK" ] && VPN_IPSEC_PSK="$YOUR_IPSEC_PSK"
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[ -n "$YOUR_USERNAME" ] && VPN_USER="$YOUR_USERNAME"
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[ -n "$YOUR_PASSWORD" ] && VPN_PASSWORD="$YOUR_PASSWORD"
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if [ -z "$VPN_IPSEC_PSK" ] && [ -z "$VPN_USER" ] && [ -z "$VPN_PASSWORD" ]; then
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bigecho "VPN credentials not set by user. Generating random PSK and password..."
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VPN_IPSEC_PSK=$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 20)
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VPN_USER=vpnuser
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VPN_PASSWORD=$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 16)
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fi
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if [ -z "$VPN_IPSEC_PSK" ] || [ -z "$VPN_USER" ] || [ -z "$VPN_PASSWORD" ]; then
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exiterr "All VPN credentials must be specified. Edit the script and re-enter them."
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fi
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if printf '%s' "$VPN_IPSEC_PSK $VPN_USER $VPN_PASSWORD" | LC_ALL=C grep -q '[^ -~]\+'; then
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exiterr "VPN credentials must not contain non-ASCII characters."
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fi
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case "$VPN_IPSEC_PSK $VPN_USER $VPN_PASSWORD" in
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*[\\\"\']*)
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exiterr "VPN credentials must not contain these special characters: \\ \" '"
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;;
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esac
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if { [ -n "$VPN_DNS_SRV1" ] && ! check_ip "$VPN_DNS_SRV1"; } \
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|| { [ -n "$VPN_DNS_SRV2" ] && ! check_ip "$VPN_DNS_SRV2"; } then
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exiterr "The DNS server specified is invalid."
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fi
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bigecho "VPN setup in progress... Please be patient."
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# Create and change to working dir
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mkdir -p /opt/src
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cd /opt/src || exit 1
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bigecho "Installing packages required for setup..."
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yum -y install wget bind-utils openssl tar \
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iptables iproute gawk grep sed net-tools || exiterr2
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bigecho "Trying to auto discover IP of this server..."
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cat <<'EOF'
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In case the script hangs here for more than a few minutes,
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press Ctrl-C to abort. Then edit it and manually enter IP.
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EOF
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# In case auto IP discovery fails, enter server's public IP here.
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PUBLIC_IP=${VPN_PUBLIC_IP:-''}
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[ -z "$PUBLIC_IP" ] && PUBLIC_IP=$(dig @resolver1.opendns.com -t A -4 myip.opendns.com +short)
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check_ip "$PUBLIC_IP" || PUBLIC_IP=$(wget -t 3 -T 15 -qO- http://ipv4.icanhazip.com)
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check_ip "$PUBLIC_IP" || exiterr "Cannot detect this server's public IP. Edit the script and manually enter it."
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bigecho "Adding the EPEL repository..."
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amazon-linux-extras install epel -y || exiterr2
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bigecho "Installing packages required for the VPN..."
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REPO1='--enablerepo=epel'
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yum -y install nss-devel nspr-devel pkgconfig pam-devel \
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libcap-ng-devel libselinux-devel curl-devel nss-tools \
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flex bison gcc make ppp \
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systemd-devel iptables-services \
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libevent-devel fipscheck-devel || exiterr2
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yum "$REPO1" -y install xl2tpd || exiterr2
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bigecho "Installing Fail2Ban to protect SSH..."
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yum "$REPO1" -y install fail2ban || exiterr2
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bigecho "Compiling and installing Libreswan..."
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SWAN_VER=4.1
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swan_file="libreswan-$SWAN_VER.tar.gz"
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swan_url1="https://github.com/libreswan/libreswan/archive/v$SWAN_VER.tar.gz"
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swan_url2="https://download.libreswan.org/$swan_file"
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if ! { wget -t 3 -T 30 -nv -O "$swan_file" "$swan_url1" || wget -t 3 -T 30 -nv -O "$swan_file" "$swan_url2"; }; then
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exit 1
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fi
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/bin/rm -rf "/opt/src/libreswan-$SWAN_VER"
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tar xzf "$swan_file" && /bin/rm -f "$swan_file"
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cd "libreswan-$SWAN_VER" || exit 1
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sed -i 's/ sysv )/ sysvinit )/' programs/setup/setup.in
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cat > Makefile.inc.local <<'EOF'
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WERROR_CFLAGS=-w
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USE_DNSSEC=false
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USE_DH2=true
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USE_NSS_KDF=false
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FINALNSSDIR=/etc/ipsec.d
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EOF
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if ! grep -qs IFLA_XFRM_LINK /usr/include/linux/if_link.h; then
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echo "USE_XFRM_INTERFACE_IFLA_HEADER=true" >> Makefile.inc.local
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fi
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NPROCS=$(grep -c ^processor /proc/cpuinfo)
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[ -z "$NPROCS" ] && NPROCS=1
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make "-j$((NPROCS+1))" -s base && make -s install-base
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cd /opt/src || exit 1
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/bin/rm -rf "/opt/src/libreswan-$SWAN_VER"
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if ! /usr/local/sbin/ipsec --version 2>/dev/null | grep -qF "$SWAN_VER"; then
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exiterr "Libreswan $SWAN_VER failed to build."
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fi
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bigecho "Creating VPN configuration..."
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L2TP_NET=${VPN_L2TP_NET:-'192.168.42.0/24'}
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L2TP_LOCAL=${VPN_L2TP_LOCAL:-'192.168.42.1'}
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L2TP_POOL=${VPN_L2TP_POOL:-'192.168.42.10-192.168.42.250'}
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XAUTH_NET=${VPN_XAUTH_NET:-'192.168.43.0/24'}
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XAUTH_POOL=${VPN_XAUTH_POOL:-'192.168.43.10-192.168.43.250'}
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DNS_SRV1=${VPN_DNS_SRV1:-'8.8.8.8'}
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DNS_SRV2=${VPN_DNS_SRV2:-'8.8.4.4'}
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DNS_SRVS="\"$DNS_SRV1 $DNS_SRV2\""
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[ -n "$VPN_DNS_SRV1" ] && [ -z "$VPN_DNS_SRV2" ] && DNS_SRVS="$DNS_SRV1"
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# Create IPsec config
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conf_bk "/etc/ipsec.conf"
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cat > /etc/ipsec.conf <<EOF
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version 2.0
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config setup
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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
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interfaces=%defaultroute
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uniqueids=no
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conn shared
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left=%defaultroute
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leftid=$PUBLIC_IP
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right=%any
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encapsulation=yes
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authby=secret
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pfs=no
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rekey=no
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keyingtries=5
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dpddelay=30
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dpdtimeout=120
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dpdaction=clear
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ikev2=never
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ike=aes256-sha2,aes128-sha2,aes256-sha1,aes128-sha1,aes256-sha2;modp1024,aes128-sha1;modp1024
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phase2alg=aes_gcm-null,aes128-sha1,aes256-sha1,aes256-sha2_512,aes128-sha2,aes256-sha2
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ikelifetime=24h
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salifetime=24h
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sha2-truncbug=no
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conn l2tp-psk
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auto=add
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leftprotoport=17/1701
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rightprotoport=17/%any
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type=transport
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phase2=esp
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also=shared
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conn xauth-psk
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auto=add
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leftsubnet=0.0.0.0/0
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rightaddresspool=$XAUTH_POOL
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modecfgdns=$DNS_SRVS
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leftxauthserver=yes
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rightxauthclient=yes
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leftmodecfgserver=yes
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rightmodecfgclient=yes
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modecfgpull=yes
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xauthby=file
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fragmentation=yes
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cisco-unity=yes
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also=shared
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include /etc/ipsec.d/*.conf
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EOF
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# Specify IPsec PSK
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conf_bk "/etc/ipsec.secrets"
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cat > /etc/ipsec.secrets <<EOF
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%any %any : PSK "$VPN_IPSEC_PSK"
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EOF
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# Create xl2tpd config
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conf_bk "/etc/xl2tpd/xl2tpd.conf"
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cat > /etc/xl2tpd/xl2tpd.conf <<EOF
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[global]
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port = 1701
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[lns default]
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ip range = $L2TP_POOL
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local ip = $L2TP_LOCAL
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require chap = yes
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refuse pap = yes
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require authentication = yes
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name = l2tpd
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pppoptfile = /etc/ppp/options.xl2tpd
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length bit = yes
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EOF
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# Set xl2tpd options
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conf_bk "/etc/ppp/options.xl2tpd"
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cat > /etc/ppp/options.xl2tpd <<EOF
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+mschap-v2
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ipcp-accept-local
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ipcp-accept-remote
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noccp
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auth
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mtu 1280
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mru 1280
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proxyarp
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lcp-echo-failure 4
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lcp-echo-interval 30
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connect-delay 5000
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ms-dns $DNS_SRV1
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EOF
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if [ -z "$VPN_DNS_SRV1" ] || [ -n "$VPN_DNS_SRV2" ]; then
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cat >> /etc/ppp/options.xl2tpd <<EOF
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ms-dns $DNS_SRV2
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EOF
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fi
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# Create VPN credentials
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conf_bk "/etc/ppp/chap-secrets"
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cat > /etc/ppp/chap-secrets <<EOF
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"$VPN_USER" l2tpd "$VPN_PASSWORD" *
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EOF
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conf_bk "/etc/ipsec.d/passwd"
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VPN_PASSWORD_ENC=$(openssl passwd -1 "$VPN_PASSWORD")
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cat > /etc/ipsec.d/passwd <<EOF
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$VPN_USER:$VPN_PASSWORD_ENC:xauth-psk
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EOF
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bigecho "Updating sysctl settings..."
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if ! grep -qs "hwdsl2 VPN script" /etc/sysctl.conf; then
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conf_bk "/etc/sysctl.conf"
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cat >> /etc/sysctl.conf <<EOF
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# Added by hwdsl2 VPN script
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kernel.msgmnb = 65536
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kernel.msgmax = 65536
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net.ipv4.ip_forward = 1
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net.ipv4.conf.all.accept_redirects = 0
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net.ipv4.conf.all.send_redirects = 0
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net.ipv4.conf.all.rp_filter = 0
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net.ipv4.conf.default.accept_redirects = 0
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net.ipv4.conf.default.send_redirects = 0
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net.ipv4.conf.default.rp_filter = 0
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net.ipv4.conf.$NET_IFACE.send_redirects = 0
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net.ipv4.conf.$NET_IFACE.rp_filter = 0
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net.core.wmem_max = 12582912
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net.core.rmem_max = 12582912
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net.ipv4.tcp_rmem = 10240 87380 12582912
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net.ipv4.tcp_wmem = 10240 87380 12582912
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EOF
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fi
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F2B_FILE=/etc/fail2ban/jail.local
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if [ ! -f "$F2B_FILE" ]; then
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bigecho "Creating basic Fail2Ban rules..."
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cat > "$F2B_FILE" <<'EOF'
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[ssh-iptables]
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enabled = true
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filter = sshd
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logpath = /var/log/secure
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action = iptables[name=SSH, port=ssh, protocol=tcp]
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EOF
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fi
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bigecho "Updating IPTables rules..."
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IPT_FILE=/etc/sysconfig/iptables
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ipt_flag=0
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if ! grep -qs "hwdsl2 VPN script" "$IPT_FILE"; then
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ipt_flag=1
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fi
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if [ "$ipt_flag" = "1" ]; then
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service fail2ban stop >/dev/null 2>&1
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iptables-save > "$IPT_FILE.old-$SYS_DT"
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iptables -I INPUT 1 -p udp --dport 1701 -m policy --dir in --pol none -j DROP
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iptables -I INPUT 2 -m conntrack --ctstate INVALID -j DROP
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iptables -I INPUT 3 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
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iptables -I INPUT 4 -p udp -m multiport --dports 500,4500 -j ACCEPT
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iptables -I INPUT 5 -p udp --dport 1701 -m policy --dir in --pol ipsec -j ACCEPT
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iptables -I INPUT 6 -p udp --dport 1701 -j DROP
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iptables -I FORWARD 1 -m conntrack --ctstate INVALID -j DROP
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iptables -I FORWARD 2 -i "$NET_IFACE" -o ppp+ -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
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iptables -I FORWARD 3 -i ppp+ -o "$NET_IFACE" -j ACCEPT
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iptables -I FORWARD 4 -i ppp+ -o ppp+ -s "$L2TP_NET" -d "$L2TP_NET" -j ACCEPT
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iptables -I FORWARD 5 -i "$NET_IFACE" -d "$XAUTH_NET" -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
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iptables -I FORWARD 6 -s "$XAUTH_NET" -o "$NET_IFACE" -j ACCEPT
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# Uncomment to disallow traffic between VPN clients
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# iptables -I FORWARD 2 -i ppp+ -o ppp+ -s "$L2TP_NET" -d "$L2TP_NET" -j DROP
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# iptables -I FORWARD 3 -s "$XAUTH_NET" -d "$XAUTH_NET" -j DROP
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iptables -t nat -I POSTROUTING -s "$XAUTH_NET" -o "$NET_IFACE" -m policy --dir out --pol none -j MASQUERADE
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iptables -t nat -I POSTROUTING -s "$L2TP_NET" -o "$NET_IFACE" -j MASQUERADE
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echo "# Modified by hwdsl2 VPN script" > "$IPT_FILE"
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iptables -A FORWARD -j DROP
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iptables-save >> "$IPT_FILE"
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fi
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bigecho "Enabling services on boot..."
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systemctl --now mask firewalld 2>/dev/null
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systemctl enable iptables fail2ban 2>/dev/null
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if ! grep -qs "hwdsl2 VPN script" /etc/rc.local; then
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if [ -f /etc/rc.local ]; then
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conf_bk "/etc/rc.local"
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else
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echo '#!/bin/sh' > /etc/rc.local
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fi
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cat >> /etc/rc.local <<'EOF'
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# Added by hwdsl2 VPN script
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(sleep 15
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service ipsec restart
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service xl2tpd restart
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echo 1 > /proc/sys/net/ipv4/ip_forward)&
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EOF
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fi
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bigecho "Starting services..."
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restorecon /etc/ipsec.d/*db 2>/dev/null
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restorecon /usr/local/sbin -Rv 2>/dev/null
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restorecon /usr/local/libexec/ipsec -Rv 2>/dev/null
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sysctl -e -q -p
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chmod +x /etc/rc.local
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chmod 600 /etc/ipsec.secrets* /etc/ppp/chap-secrets* /etc/ipsec.d/passwd*
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iptables-restore < "$IPT_FILE"
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# Fix xl2tpd if l2tp_ppp is unavailable
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if ! modprobe -q l2tp_ppp; then
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sed -i '/^ExecStartPre=\//s/=/=-/' /usr/lib/systemd/system/xl2tpd.service
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systemctl daemon-reload
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fi
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mkdir -p /run/pluto
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service fail2ban restart 2>/dev/null
|
|
service ipsec restart 2>/dev/null
|
|
service xl2tpd restart 2>/dev/null
|
|
|
|
swan_ver_url="https://dl.ls20.com/v1/amzn/2/swanver?arch=$os_arch&ver=$SWAN_VER"
|
|
swan_ver_latest=$(wget -t 3 -T 15 -qO- "$swan_ver_url")
|
|
if printf '%s' "$swan_ver_latest" | grep -Eq '^([3-9]|[1-9][0-9])\.([0-9]|[1-9][0-9])$' \
|
|
&& [ "$SWAN_VER" != "$swan_ver_latest" ]; then
|
|
cat <<EOF
|
|
|
|
Note: A newer version of Libreswan ($swan_ver_latest) is available. To update, run:
|
|
wget https://git.io/vpnupgrade-amzn -O vpnupgrade.sh
|
|
sudo sh vpnupgrade.sh
|
|
EOF
|
|
fi
|
|
|
|
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: $VPN_PASSWORD
|
|
|
|
Write these down. You'll need them to connect!
|
|
|
|
Important notes: https://git.io/vpnnotes
|
|
Setup VPN clients: https://git.io/vpnclients
|
|
IKEv2 guide: https://git.io/ikev2
|
|
|
|
================================================
|
|
|
|
EOF
|
|
|
|
}
|
|
|
|
## Defer setup until we have the complete script
|
|
vpnsetup "$@"
|
|
|
|
exit 0
|