#!/bin/bash # # Script for automatic setup of an IPsec VPN server on CentOS/RHEL, Rocky Linux, # AlmaLinux and Oracle Linux # # 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) 2015-2022 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 special characters within values: \ " ' YOUR_IPSEC_PSK='' YOUR_USERNAME='' YOUR_PASSWORD='' # VPN client setup: https://vpnsetup.net/clients # ===================================================== export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" SYS_DT=$(date +%F-%T | tr ':' '_') 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 "## $1"; } check_ip() { IP_REGEX='^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$' printf '%s' "$1" | tr -d '\n' | grep -Eq "$IP_REGEX" } check_dns_name() { FQDN_REGEX='^([a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}$' printf '%s' "$1" | tr -d '\n' | grep -Eq "$FQDN_REGEX" } check_root() { if [ "$(id -u)" != 0 ]; then exiterr "Script must be run as root. Try 'sudo bash $0'" fi } check_vz() { if [ -f /proc/user_beancounters ]; then exiterr "OpenVZ VPS is not supported." fi } check_lxc() { # shellcheck disable=SC2154 if [ "$container" = "lxc" ] && [ ! -e /dev/ppp ]; then cat 1>&2 <<'EOF' Error: /dev/ppp is missing. LXC containers require configuration. See: https://github.com/hwdsl2/setup-ipsec-vpn/issues/1014 EOF exit 1 fi } check_os() { rh_file="/etc/redhat-release" if [ -f "$rh_file" ]; then os_type=centos if grep -q "Red Hat" "$rh_file"; then os_type=rhel fi [ -f /etc/oracle-release ] && os_type=ol grep -qi rocky "$rh_file" && os_type=rocky grep -qi alma "$rh_file" && os_type=alma if grep -q "release 7" "$rh_file"; then os_ver=7 elif grep -q "release 8" "$rh_file"; then os_ver=8 grep -qi stream "$rh_file" && os_ver=8s if [ "$os_type$os_ver" = "centos8" ]; then exiterr "CentOS Linux 8 is EOL and not supported." fi elif grep -q "release 9" "$rh_file"; then os_ver=9 grep -qi stream "$rh_file" && os_ver=9s else exiterr "This script only supports CentOS/RHEL 7-9." fi else cat 1>&2 <<'EOF' Error: This script only supports one of the following OS: CentOS/RHEL, Rocky Linux, AlmaLinux or Oracle Linux EOF exit 1 fi } check_iface() { def_iface=$(route 2>/dev/null | grep -m 1 '^default' | grep -o '[^ ]*$') [ -z "$def_iface" ] && def_iface=$(ip -4 route list 0/0 2>/dev/null | grep -m 1 -Po '(?<=dev )(\S+)') def_state=$(cat "/sys/class/net/$def_iface/operstate" 2>/dev/null) if [ -n "$def_state" ] && [ "$def_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="$def_iface" else eth0_state=$(cat "/sys/class/net/eth0/operstate" 2>/dev/null) if [ -z "$eth0_state" ] || [ "$eth0_state" = "down" ]; then exiterr "Could not detect the default network interface." fi NET_IFACE=eth0 fi } check_creds() { [ -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/null | head -c 20) VPN_USER=vpnuser VPN_PASSWORD=$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' /dev/null | head -c 16) fi if [ -z "$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 $VPN_PASSWORD" in *[\\\"\']*) exiterr "VPN credentials must not contain these special characters: \\ \" '" ;; esac } check_dns() { if { [ -n "$VPN_DNS_SRV1" ] && ! check_ip "$VPN_DNS_SRV1"; } \ || { [ -n "$VPN_DNS_SRV2" ] && ! check_ip "$VPN_DNS_SRV2"; }; then exiterr "The DNS server specified is invalid." fi } check_server_dns() { if [ -n "$VPN_DNS_NAME" ] && ! check_dns_name "$VPN_DNS_NAME"; then exiterr "Invalid DNS name. 'VPN_DNS_NAME' must be a fully qualified domain name (FQDN)." fi } check_client_name() { if [ -n "$VPN_CLIENT_NAME" ]; then name_len="$(printf '%s' "$VPN_CLIENT_NAME" | wc -m)" if [ "$name_len" -gt "64" ] || printf '%s' "$VPN_CLIENT_NAME" | LC_ALL=C grep -q '[^A-Za-z0-9_-]\+' \ || case $VPN_CLIENT_NAME in -*) true ;; *) false ;; esac; then exiterr "Invalid client name. Use one word only, no special characters except '-' and '_'." fi fi } check_subnets() { if [ -s /etc/ipsec.conf ] && grep -qs "hwdsl2 VPN script" /etc/sysctl.conf; then L2TP_NET=${VPN_L2TP_NET:-'192.168.42.0/24'} XAUTH_NET=${VPN_XAUTH_NET:-'192.168.43.0/24'} if ! grep -q "$L2TP_NET" /etc/ipsec.conf \ || ! grep -q "$XAUTH_NET" /etc/ipsec.conf; then echo "Error: The custom VPN subnets specified do not match initial install." >&2 echo " See Advanced usage -> Customize VPN subnets for more information." >&2 exit 1 fi fi } start_setup() { bigecho "VPN setup in progress... Please be patient." mkdir -p /opt/src cd /opt/src || exit 1 } install_setup_pkgs() { bigecho "Installing packages required for setup..." ( set -x yum -y -q install wget bind-utils openssl tar \ iptables iproute gawk grep sed net-tools >/dev/null \ || yum -y -q install wget bind-utils openssl tar \ iptables iproute gawk grep sed net-tools >/dev/null ) || exiterr2 } detect_ip() { bigecho "Trying to auto discover IP of this server..." public_ip=${VPN_PUBLIC_IP:-''} check_ip "$public_ip" || public_ip=$(dig @resolver1.opendns.com -t A -4 myip.opendns.com +short) check_ip "$public_ip" || public_ip=$(wget -t 3 -T 15 -qO- http://ipv4.icanhazip.com) check_ip "$public_ip" || exiterr "Cannot detect this server's public IP. Define it as variable 'VPN_PUBLIC_IP' and re-run this script." } add_epel_repo() { bigecho "Adding the EPEL repository..." epel_url="https://dl.fedoraproject.org/pub/epel/epel-release-latest-$(rpm -E '%{rhel}').noarch.rpm" ( set -x yum -y -q install epel-release >/dev/null 2>&1 || yum -y -q install "$epel_url" >/dev/null ) || exiterr2 } install_vpn_pkgs_1() { bigecho "Installing packages required for the VPN..." erp="--enablerepo" rp1="$erp=epel" rp2="$erp=*server-*optional*" rp3="$erp=*releases-optional*" if [ "$os_type" = "ol" ]; then if [ "$os_ver" = "9" ]; then rp1="$erp=ol9_developer_EPEL" elif [ "$os_ver" = "8" ]; then rp1="$erp=ol8_developer_EPEL" else rp3="$erp=ol7_optional_latest" fi fi ( set -x yum -y -q install nss-devel nspr-devel pkgconfig pam-devel \ libcap-ng-devel libselinux-devel curl-devel nss-tools \ flex bison gcc make util-linux ppp >/dev/null ) || exiterr2 } install_vpn_pkgs_2() { ( set -x yum "$rp1" -y -q install xl2tpd >/dev/null 2>&1 ) || exiterr2 } install_vpn_pkgs_3() { use_nft=0 p1=systemd-devel p2=libevent-devel p3=fipscheck-devel p4=iptables-services if [ "$os_ver" = "7" ]; then ( set -x yum "$rp2" "$rp3" -y -q install $p1 $p2 $p3 $p4 >/dev/null ) || exiterr2 else ( set -x yum -y -q install $p1 $p2 >/dev/null ) || exiterr2 if [ "$os_ver" = "9" ] || [ "$os_ver" = "9s" ] \ || systemctl is-active --quiet firewalld \ || systemctl is-active --quiet nftables \ || grep -qs "hwdsl2 VPN script" /etc/sysconfig/nftables.conf; then use_nft=1 p4=nftables fi ( set -x yum -y -q install $p4 >/dev/null ) || exiterr2 fi } install_fail2ban() { bigecho "Installing Fail2Ban to protect SSH..." ( set -x yum "$rp1" -y -q install fail2ban >/dev/null ) || exiterr2 } get_helper_scripts() { bigecho "Downloading helper scripts..." base_url1="https://github.com/hwdsl2/setup-ipsec-vpn/raw/master/extras" base_url2="https://gitlab.com/hwdsl2/setup-ipsec-vpn/-/raw/master/extras" ikev2_url1="$base_url1/ikev2setup.sh" ikev2_url2="$base_url2/ikev2setup.sh" add_url1="$base_url1/add_vpn_user.sh" add_url2="$base_url2/add_vpn_user.sh" del_url1="$base_url1/del_vpn_user.sh" del_url2="$base_url2/del_vpn_user.sh" cd /opt/src || exit 1 printf '%s' "+ " for sc in ikev2.sh addvpnuser.sh delvpnuser.sh; do [ "$sc" = "ikev2.sh" ] && dl_url1="$ikev2_url1" && dl_url2="$ikev2_url2" [ "$sc" = "addvpnuser.sh" ] && dl_url1="$add_url1" && dl_url2="$add_url2" [ "$sc" = "delvpnuser.sh" ] && dl_url1="$del_url1" && dl_url2="$del_url2" printf '%s' "$sc " wget -t 3 -T 30 -q -O "$sc" "$dl_url1" \ || wget -t 3 -T 30 -q -O "$sc" "$dl_url2" || /bin/rm -f "$sc" [ -s "$sc" ] && chmod +x "$sc" && ln -s "/opt/src/$sc" /usr/bin 2>/dev/null done echo } get_swan_ver() { SWAN_VER=4.7 base_url="https://github.com/hwdsl2/vpn-extras/releases/download/v1.0.0" swan_ver_url="$base_url/v1-$os_type-$os_ver-swanver" swan_ver_latest=$(wget -t 3 -T 15 -qO- "$swan_ver_url" 2>/dev/null | head -n 1) [ -z "$swan_ver_latest" ] && swan_ver_latest=$(curl -fsL "$swan_ver_url" 2>/dev/null | head -n 1) if printf '%s' "$swan_ver_latest" | grep -Eq '^([3-9]|[1-9][0-9]{1,2})(\.([0-9]|[1-9][0-9]{1,2})){1,2}$'; then SWAN_VER="$swan_ver_latest" fi } check_libreswan() { check_result=0 ipsec_ver=$(/usr/local/sbin/ipsec --version 2>/dev/null) swan_ver_old=$(printf '%s' "$ipsec_ver" | sed -e 's/.*Libreswan U\?//' -e 's/\( (\|\/K\).*//') ipsec_bin="/usr/local/sbin/ipsec" if [ -n "$swan_ver_old" ] && printf '%s' "$ipsec_ver" | grep -qi 'libreswan' \ && [ "$(find "$ipsec_bin" -mmin -10080)" ]; then check_result=1 return 0 fi get_swan_ver if [ -s "$ipsec_bin" ] && [ "$swan_ver_old" = "$SWAN_VER" ]; then touch "$ipsec_bin" fi [ "$swan_ver_old" = "$SWAN_VER" ] && check_result=1 } get_libreswan() { if [ "$check_result" = "0" ]; then bigecho "Downloading Libreswan..." cd /opt/src || exit 1 swan_file="libreswan-$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" ( set -x wget -t 3 -T 30 -q -O "$swan_file" "$swan_url1" || wget -t 3 -T 30 -q -O "$swan_file" "$swan_url2" ) || exit 1 /bin/rm -rf "/opt/src/libreswan-$SWAN_VER" tar xzf "$swan_file" && /bin/rm -f "$swan_file" else bigecho "Libreswan $swan_ver_old is already installed, skipping..." fi } install_libreswan() { if [ "$check_result" = "0" ]; then bigecho "Compiling and installing Libreswan, please wait..." cd "libreswan-$SWAN_VER" || exit 1 cat > Makefile.inc.local <<'EOF' WERROR_CFLAGS=-w -s USE_DNSSEC=false USE_DH2=true USE_NSS_KDF=false FINALNSSDIR=/etc/ipsec.d EOF if ! grep -qs IFLA_XFRM_LINK /usr/include/linux/if_link.h; then echo "USE_XFRM_INTERFACE_IFLA_HEADER=true" >> Makefile.inc.local fi NPROCS=$(grep -c ^processor /proc/cpuinfo) [ -z "$NPROCS" ] && NPROCS=1 ( set -x make "-j$((NPROCS+1))" -s base >/dev/null && make -s install-base >/dev/null ) cd /opt/src || exit 1 /bin/rm -rf "/opt/src/libreswan-$SWAN_VER" if ! /usr/local/sbin/ipsec --version 2>/dev/null | grep -qF "$SWAN_VER"; then exiterr "Libreswan $SWAN_VER failed to build." fi fi } create_vpn_config() { bigecho "Creating VPN configuration..." L2TP_NET=${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'} DNS_SRVS="\"$DNS_SRV1 $DNS_SRV2\"" [ -n "$VPN_DNS_SRV1" ] && [ -z "$VPN_DNS_SRV2" ] && DNS_SRVS="$DNS_SRV1" # Create IPsec config conf_bk "/etc/ipsec.conf" cat > /etc/ipsec.conf < /etc/ipsec.secrets < /etc/xl2tpd/xl2tpd.conf < /etc/ppp/options.xl2tpd <> /etc/ppp/options.xl2tpd < /etc/ppp/chap-secrets < /etc/ipsec.d/passwd < "$F2B_FILE" <<'EOF' [ssh-iptables] enabled = true filter = sshd logpath = /var/log/secure EOF if [ "$use_nft" = "1" ]; then cat >> "$F2B_FILE" <<'EOF' port = ssh banaction = nftables-multiport[blocktype=drop] EOF else cat >> "$F2B_FILE" <<'EOF' action = iptables[name=SSH, port=ssh, protocol=tcp] EOF fi fi } update_sysctl() { bigecho "Updating sysctl settings..." if ! grep -qs "hwdsl2 VPN script" /etc/sysctl.conf; then conf_bk "/etc/sysctl.conf" cat >> /etc/sysctl.conf </dev/null 2>&1 if [ "$use_nft" = "1" ]; then nft list ruleset > "$IPT_FILE.old-$SYS_DT" chmod 600 "$IPT_FILE.old-$SYS_DT" else iptables-save > "$IPT_FILE.old-$SYS_DT" fi $ipi 1 -p udp --dport 1701 -m policy --dir in --pol none -j DROP $ipi 2 -m conntrack --ctstate INVALID -j DROP $ipi 3 -m conntrack --ctstate "$res" -j ACCEPT $ipi 4 -p udp -m multiport --dports 500,4500 -j ACCEPT $ipi 5 -p udp --dport 1701 -m policy --dir in --pol ipsec -j ACCEPT $ipi 6 -p udp --dport 1701 -j DROP $ipf 1 -m conntrack --ctstate INVALID -j DROP $ipf 2 -i "$NET_IFACE" -o ppp+ -m conntrack --ctstate "$res" -j ACCEPT $ipf 3 -i ppp+ -o "$NET_IFACE" -j ACCEPT $ipf 4 -i ppp+ -o ppp+ -j ACCEPT $ipf 5 -i "$NET_IFACE" -d "$XAUTH_NET" -m conntrack --ctstate "$res" -j ACCEPT $ipf 6 -s "$XAUTH_NET" -o "$NET_IFACE" -j ACCEPT $ipf 7 -s "$XAUTH_NET" -o ppp+ -j ACCEPT if [ "$use_nft" != "1" ]; then iptables -A FORWARD -j DROP fi $ipp -s "$XAUTH_NET" -o "$NET_IFACE" -m policy --dir out --pol none -j MASQUERADE $ipp -s "$L2TP_NET" -o "$NET_IFACE" -j MASQUERADE echo "# Modified by hwdsl2 VPN script" > "$IPT_FILE" if [ "$use_nft" = "1" ]; then for vport in 500 4500 1701; do $nff filter_INPUT udp dport "$vport" accept 2>/dev/null $nfn allow udp dport "$vport" accept 2>/dev/null done for vnet in "$L2TP_NET" "$XAUTH_NET"; do for vdir in saddr daddr; do $nff filter_FORWARD ip "$vdir" "$vnet" accept 2>/dev/null $nfn FORWARD ip "$vdir" "$vnet" accept 2>/dev/null done done echo "flush ruleset" >> "$IPT_FILE" nft list ruleset >> "$IPT_FILE" else iptables-save >> "$IPT_FILE" fi fi } fix_nss_config() { nss_conf="/etc/crypto-policies/back-ends/nss.config" if [ -s "$nss_conf" ]; then if ! grep -q ":SHA1:" "$nss_conf" \ && ! grep -q " allow=SHA1:" "$nss_conf"; then sed -i "/ALL allow=/s/ allow=/ allow=SHA1:/" "$nss_conf" fi fi } apply_gcp_mtu_fix() { if dmidecode -s system-product-name 2>/dev/null | grep -qi 'Google Compute Engine' \ && ifconfig 2>/dev/null | grep "$NET_IFACE" | head -n 1 | grep -qi 'mtu 1460'; then bigecho "Applying fix for MTU size..." ifconfig "$NET_IFACE" mtu 1500 dh_file="/etc/dhcp/dhclient.conf" if grep -qs "send host-name" "$dh_file" \ && ! grep -qs "interface-mtu 1500" "$dh_file"; then sed -i".old-$SYS_DT" \ "/send host-name/a \interface \"$NET_IFACE\" {\ndefault interface-mtu 1500;\nsupersede interface-mtu 1500;\n}" \ "$dh_file" fi fi } enable_on_boot() { bigecho "Enabling services on boot..." systemctl --now mask firewalld 2>/dev/null if [ "$os_type$os_ver" = "ol9" ]; then systemctl enable nftables 2>/dev/null elif [ "$use_nft" = "1" ]; then systemctl enable nftables fail2ban 2>/dev/null else 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 service ipsec restart service xl2tpd restart echo 1 > /proc/sys/net/ipv4/ip_forward)& EOF fi } start_services() { bigecho "Starting services..." sysctl -e -q -p chmod +x /etc/rc.local chmod 600 /etc/ipsec.secrets* /etc/ppp/chap-secrets* /etc/ipsec.d/passwd* 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 if [ "$use_nft" = "1" ]; then nft -f "$IPT_FILE" else iptables-restore < "$IPT_FILE" fi # Fix xl2tpd if l2tp_ppp is unavailable if ! modprobe -q l2tp_ppp; then sed -i '/^ExecStartPre=\//s/=/=-/' /usr/lib/systemd/system/xl2tpd.service systemctl daemon-reload fi mkdir -p /run/pluto service fail2ban restart 2>/dev/null service ipsec restart 2>/dev/null service xl2tpd restart 2>/dev/null } show_vpn_info() { cat <