419 lines
15 KiB
Bash
Executable file
419 lines
15 KiB
Bash
Executable file
#!/bin/bash
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# OpenVPN road warrior installer for Debian, Ubuntu and CentOS
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# This script will work on Debian, Ubuntu, CentOS and probably other distros
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# of the same families, although no support is offered for them. It isn't
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# bulletproof but it will probably work if you simply want to setup a VPN on
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# your Debian/Ubuntu/CentOS box. It has been designed to be as unobtrusive and
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# universal as possible.
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# Detect Debian users running the script with "sh" instead of bash
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if readlink /proc/$$/exe | grep -qs "dash"; then
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echo "This script needs to be run with bash, not sh"
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exit 1
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fi
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if [[ "$EUID" -ne 0 ]]; then
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echo "Sorry, you need to run this as root"
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exit 2
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fi
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if [[ ! -e /dev/net/tun ]]; then
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echo "The TUN device is not available
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You need to enable TUN before running this script"
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exit 3
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fi
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if grep -qs "CentOS release 5" "/etc/redhat-release"; then
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echo "CentOS 5 is too old and not supported"
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exit 4
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fi
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if [[ -e /etc/debian_version ]]; then
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OS=debian
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GROUPNAME=nogroup
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RCLOCAL='/etc/rc.local'
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elif [[ -e /etc/centos-release || -e /etc/redhat-release ]]; then
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OS=centos
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GROUPNAME=nobody
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RCLOCAL='/etc/rc.d/rc.local'
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else
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echo "Looks like you aren't running this installer on Debian, Ubuntu or CentOS"
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exit 5
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fi
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newclient () {
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# Generates the custom client.ovpn
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cp /etc/openvpn/client-common.txt ~/$1.ovpn
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echo "<ca>" >> ~/$1.ovpn
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cat /etc/openvpn/easy-rsa/pki/ca.crt >> ~/$1.ovpn
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echo "</ca>" >> ~/$1.ovpn
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echo "<cert>" >> ~/$1.ovpn
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cat /etc/openvpn/easy-rsa/pki/issued/$1.crt >> ~/$1.ovpn
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echo "</cert>" >> ~/$1.ovpn
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echo "<key>" >> ~/$1.ovpn
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cat /etc/openvpn/easy-rsa/pki/private/$1.key >> ~/$1.ovpn
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echo "</key>" >> ~/$1.ovpn
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echo "<tls-auth>" >> ~/$1.ovpn
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cat /etc/openvpn/ta.key >> ~/$1.ovpn
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echo "</tls-auth>" >> ~/$1.ovpn
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}
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# Try to get our IP from the system and fallback to the Internet.
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# I do this to make the script compatible with NATed servers (lowendspirit.com)
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# and to avoid getting an IPv6.
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IP=$(ip addr | grep 'inet' | grep -v inet6 | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | grep -o -E '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | head -1)
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if [[ "$IP" = "" ]]; then
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IP=$(wget -4qO- "http://whatismyip.akamai.com/")
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fi
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if [[ -e /etc/openvpn/server.conf ]]; then
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while :
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do
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clear
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echo "Looks like OpenVPN is already installed"
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echo ""
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echo "What do you want to do?"
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echo " 1) Add a new user"
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echo " 2) Revoke an existing user"
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echo " 3) Remove OpenVPN"
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echo " 4) Exit"
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read -p "Select an option [1-4]: " option
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case $option in
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1)
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echo ""
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echo "Tell me a name for the client certificate"
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echo "Please, use one word only, no special characters"
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read -p "Client name: " -e -i client CLIENT
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cd /etc/openvpn/easy-rsa/
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./easyrsa build-client-full $CLIENT nopass
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# Generates the custom client.ovpn
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newclient "$CLIENT"
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echo ""
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echo "Client $CLIENT added, configuration is available at" ~/"$CLIENT.ovpn"
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exit
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;;
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2)
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# This option could be documented a bit better and maybe even be simplimplified
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# ...but what can I say, I want some sleep too
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NUMBEROFCLIENTS=$(tail -n +2 /etc/openvpn/easy-rsa/pki/index.txt | grep -c "^V")
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if [[ "$NUMBEROFCLIENTS" = '0' ]]; then
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echo ""
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echo "You have no existing clients!"
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exit 6
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fi
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echo ""
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echo "Select the existing client certificate you want to revoke"
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tail -n +2 /etc/openvpn/easy-rsa/pki/index.txt | grep "^V" | cut -d '=' -f 2 | nl -s ') '
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if [[ "$NUMBEROFCLIENTS" = '1' ]]; then
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read -p "Select one client [1]: " CLIENTNUMBER
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else
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read -p "Select one client [1-$NUMBEROFCLIENTS]: " CLIENTNUMBER
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fi
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CLIENT=$(tail -n +2 /etc/openvpn/easy-rsa/pki/index.txt | grep "^V" | cut -d '=' -f 2 | sed -n "$CLIENTNUMBER"p)
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cd /etc/openvpn/easy-rsa/
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./easyrsa --batch revoke $CLIENT
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./easyrsa gen-crl
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rm -rf pki/reqs/$CLIENT.req
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rm -rf pki/private/$CLIENT.key
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rm -rf pki/issued/$CLIENT.crt
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rm -rf /etc/openvpn/crl.pem
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cp /etc/openvpn/easy-rsa/pki/crl.pem /etc/openvpn/crl.pem
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# CRL is read with each client connection, when OpenVPN is dropped to nobody
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chown nobody:$GROUPNAME /etc/openvpn/crl.pem
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echo ""
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echo "Certificate for client $CLIENT revoked"
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exit
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;;
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3)
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echo ""
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read -p "Do you really want to remove OpenVPN? [y/n]: " -e -i n REMOVE
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if [[ "$REMOVE" = 'y' ]]; then
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PORT=$(grep '^port ' /etc/openvpn/server.conf | cut -d " " -f 2)
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PROTOCOL=$(grep '^proto ' /etc/openvpn/server.conf | cut -d " " -f 2)
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if pgrep firewalld; then
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IP=$(firewall-cmd --direct --get-rules ipv4 nat POSTROUTING | grep '\-s 10.8.0.0/24 '"'"'!'"'"' -d 10.8.0.0/24 -j SNAT --to ' | cut -d " " -f 10)
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# Using both permanent and not permanent rules to avoid a firewalld reload.
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firewall-cmd --zone=public --remove-port=$PORT/$PROTOCOL
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firewall-cmd --zone=trusted --remove-source=10.8.0.0/24
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firewall-cmd --permanent --zone=public --remove-port=$PORT/$PROTOCOL
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firewall-cmd --permanent --zone=trusted --remove-source=10.8.0.0/24
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firewall-cmd --direct --remove-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
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firewall-cmd --permanent --direct --remove-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
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else
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IP=$(grep 'iptables -t nat -A POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to ' $RCLOCAL | cut -d " " -f 11)
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iptables -t nat -D POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
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sed -i '/iptables -t nat -A POSTROUTING -s 10.8.0.0\/24 ! -d 10.8.0.0\/24 -j SNAT --to /d' $RCLOCAL
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if iptables -L -n | grep -qE '^ACCEPT'; then
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iptables -D INPUT -p $PROTOCOL --dport $PORT -j ACCEPT
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iptables -D FORWARD -s 10.8.0.0/24 -j ACCEPT
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iptables -D FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
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sed -i "/iptables -I INPUT -p $PROTOCOL --dport $PORT -j ACCEPT/d" $RCLOCAL
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sed -i "/iptables -I FORWARD -s 10.8.0.0\/24 -j ACCEPT/d" $RCLOCAL
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sed -i "/iptables -I FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT/d" $RCLOCAL
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fi
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fi
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if hash sestatus 2>/dev/null; then
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if sestatus | grep "Current mode" | grep -qs "enforcing"; then
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if [[ "$PORT" != '1194' || "$PROTOCOL" = 'tcp' ]]; then
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semanage port -d -t openvpn_port_t -p $PROTOCOL $PORT
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fi
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fi
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fi
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if [[ "$OS" = 'debian' ]]; then
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apt-get remove --purge -y openvpn openvpn-blacklist
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else
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yum remove openvpn -y
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fi
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rm -rf /etc/openvpn
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rm -rf /usr/share/doc/openvpn*
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echo ""
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echo "OpenVPN removed!"
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else
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echo ""
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echo "Removal aborted!"
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fi
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exit
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;;
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4) exit;;
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esac
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done
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else
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clear
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echo 'Welcome to this quick OpenVPN "road warrior" installer'
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echo ""
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# OpenVPN setup and first user creation
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echo "I need to ask you a few questions before starting the setup"
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echo "You can leave the default options and just press enter if you are ok with them"
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echo ""
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echo "First I need to know the IPv4 address of the network interface you want OpenVPN"
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echo "listening to."
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read -p "IP address: " -e -i $IP IP
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echo ""
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echo "Which protocol do you want for OpenVPN connections?"
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echo " 1) UDP (recommended)"
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echo " 2) TCP"
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read -p "Protocol [1-2]: " -e -i 1 PROTOCOL
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case $PROTOCOL in
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1)
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PROTOCOL=udp
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;;
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2)
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PROTOCOL=tcp
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;;
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esac
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echo ""
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echo "What port do you want OpenVPN listening to?"
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read -p "Port: " -e -i 1194 PORT
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echo ""
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echo "Which DNS do you want to use with the VPN?"
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echo " 1) Current system resolvers"
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echo " 2) Google"
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echo " 3) OpenDNS"
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echo " 4) NTT"
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echo " 5) Hurricane Electric"
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echo " 6) Verisign"
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read -p "DNS [1-6]: " -e -i 1 DNS
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echo ""
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echo "Finally, tell me your name for the client certificate"
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echo "Please, use one word only, no special characters"
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read -p "Client name: " -e -i client CLIENT
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echo ""
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echo "Okay, that was all I needed. We are ready to setup your OpenVPN server now"
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read -n1 -r -p "Press any key to continue..."
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if [[ "$OS" = 'debian' ]]; then
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apt-get update
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apt-get install openvpn iptables openssl ca-certificates -y
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else
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# Else, the distro is CentOS
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yum install epel-release -y
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yum install openvpn iptables openssl wget ca-certificates -y
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fi
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# An old version of easy-rsa was available by default in some openvpn packages
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if [[ -d /etc/openvpn/easy-rsa/ ]]; then
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rm -rf /etc/openvpn/easy-rsa/
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fi
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# Get easy-rsa
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wget -O ~/EasyRSA-3.0.1.tgz "https://github.com/OpenVPN/easy-rsa/releases/download/3.0.1/EasyRSA-3.0.1.tgz"
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tar xzf ~/EasyRSA-3.0.1.tgz -C ~/
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mv ~/EasyRSA-3.0.1/ /etc/openvpn/
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mv /etc/openvpn/EasyRSA-3.0.1/ /etc/openvpn/easy-rsa/
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chown -R root:root /etc/openvpn/easy-rsa/
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rm -rf ~/EasyRSA-3.0.1.tgz
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cd /etc/openvpn/easy-rsa/
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# Create the PKI, set up the CA, the DH params and the server + client certificates
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./easyrsa init-pki
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./easyrsa --batch build-ca nopass
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./easyrsa gen-dh
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./easyrsa build-server-full server nopass
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./easyrsa build-client-full $CLIENT nopass
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./easyrsa gen-crl
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# Move the stuff we need
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cp pki/ca.crt pki/private/ca.key pki/dh.pem pki/issued/server.crt pki/private/server.key /etc/openvpn/easy-rsa/pki/crl.pem /etc/openvpn
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# CRL is read with each client connection, when OpenVPN is dropped to nobody
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chown nobody:$GROUPNAME /etc/openvpn/crl.pem
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# Generate key for tls-auth
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openvpn --genkey --secret /etc/openvpn/ta.key
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# Generate server.conf
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echo "port $PORT
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proto $PROTOCOL
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dev tun
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sndbuf 0
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rcvbuf 0
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ca ca.crt
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cert server.crt
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key server.key
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dh dh.pem
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auth SHA512
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tls-auth ta.key 0
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topology subnet
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server 10.8.0.0 255.255.255.0
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ifconfig-pool-persist ipp.txt" > /etc/openvpn/server.conf
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echo 'push "redirect-gateway def1 bypass-dhcp"' >> /etc/openvpn/server.conf
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# DNS
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case $DNS in
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1)
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# Obtain the resolvers from resolv.conf and use them for OpenVPN
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grep -v '#' /etc/resolv.conf | grep 'nameserver' | grep -E -o '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | while read line; do
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echo "push \"dhcp-option DNS $line\"" >> /etc/openvpn/server.conf
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done
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;;
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2)
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echo 'push "dhcp-option DNS 8.8.8.8"' >> /etc/openvpn/server.conf
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echo 'push "dhcp-option DNS 8.8.4.4"' >> /etc/openvpn/server.conf
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;;
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3)
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echo 'push "dhcp-option DNS 208.67.222.222"' >> /etc/openvpn/server.conf
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echo 'push "dhcp-option DNS 208.67.220.220"' >> /etc/openvpn/server.conf
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;;
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4)
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echo 'push "dhcp-option DNS 129.250.35.250"' >> /etc/openvpn/server.conf
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echo 'push "dhcp-option DNS 129.250.35.251"' >> /etc/openvpn/server.conf
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;;
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5)
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echo 'push "dhcp-option DNS 74.82.42.42"' >> /etc/openvpn/server.conf
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;;
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6)
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echo 'push "dhcp-option DNS 64.6.64.6"' >> /etc/openvpn/server.conf
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echo 'push "dhcp-option DNS 64.6.65.6"' >> /etc/openvpn/server.conf
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;;
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esac
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echo "keepalive 10 120
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cipher AES-256-CBC
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comp-lzo
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user nobody
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group $GROUPNAME
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persist-key
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persist-tun
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status openvpn-status.log
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verb 3
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crl-verify crl.pem" >> /etc/openvpn/server.conf
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# Enable net.ipv4.ip_forward for the system
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sed -i '/\<net.ipv4.ip_forward\>/c\net.ipv4.ip_forward=1' /etc/sysctl.conf
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if ! grep -q "\<net.ipv4.ip_forward\>" /etc/sysctl.conf; then
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echo 'net.ipv4.ip_forward=1' >> /etc/sysctl.conf
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fi
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# Avoid an unneeded reboot
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echo 1 > /proc/sys/net/ipv4/ip_forward
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if pgrep firewalld; then
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# Using both permanent and not permanent rules to avoid a firewalld
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# reload.
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# We don't use --add-service=openvpn because that would only work with
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# the default port and protocol.
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firewall-cmd --zone=public --add-port=$PORT/$PROTOCOL
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firewall-cmd --zone=trusted --add-source=10.8.0.0/24
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firewall-cmd --permanent --zone=public --add-port=$PORT/$PROTOCOL
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firewall-cmd --permanent --zone=trusted --add-source=10.8.0.0/24
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# Set NAT for the VPN subnet
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firewall-cmd --direct --add-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
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firewall-cmd --permanent --direct --add-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
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else
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# Needed to use rc.local with some systemd distros
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if [[ "$OS" = 'debian' && ! -e $RCLOCAL ]]; then
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echo '#!/bin/sh -e
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exit 0' > $RCLOCAL
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fi
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chmod +x $RCLOCAL
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# Set NAT for the VPN subnet
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iptables -t nat -A POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
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sed -i "1 a\iptables -t nat -A POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP" $RCLOCAL
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if iptables -L -n | grep -qE '^(REJECT|DROP)'; then
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# If iptables has at least one REJECT rule, we asume this is needed.
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# Not the best approach but I can't think of other and this shouldn't
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# cause problems.
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iptables -I INPUT -p $PROTOCOL --dport $PORT -j ACCEPT
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iptables -I FORWARD -s 10.8.0.0/24 -j ACCEPT
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iptables -I FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
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sed -i "1 a\iptables -I INPUT -p $PROTOCOL --dport $PORT -j ACCEPT" $RCLOCAL
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sed -i "1 a\iptables -I FORWARD -s 10.8.0.0/24 -j ACCEPT" $RCLOCAL
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sed -i "1 a\iptables -I FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT" $RCLOCAL
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fi
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fi
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# If SELinux is enabled and a custom port or TCP was selected, we need this
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if hash sestatus 2>/dev/null; then
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if sestatus | grep "Current mode" | grep -qs "enforcing"; then
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if [[ "$PORT" != '1194' || "$PROTOCOL" = 'tcp' ]]; then
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# semanage isn't available in CentOS 6 by default
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if ! hash semanage 2>/dev/null; then
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yum install policycoreutils-python -y
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fi
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semanage port -a -t openvpn_port_t -p $PROTOCOL $PORT
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fi
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fi
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fi
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# And finally, restart OpenVPN
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if [[ "$OS" = 'debian' ]]; then
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# Little hack to check for systemd
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if pgrep systemd-journal; then
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systemctl restart openvpn@server.service
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else
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/etc/init.d/openvpn restart
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fi
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else
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if pgrep systemd-journal; then
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systemctl restart openvpn@server.service
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systemctl enable openvpn@server.service
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else
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service openvpn restart
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chkconfig openvpn on
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fi
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fi
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# Try to detect a NATed connection and ask about it to potential LowEndSpirit users
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EXTERNALIP=$(wget -4qO- "http://whatismyip.akamai.com/")
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if [[ "$IP" != "$EXTERNALIP" ]]; then
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echo ""
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echo "Looks like your server is behind a NAT!"
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echo ""
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echo "If your server is NATed (e.g. LowEndSpirit), I need to know the external IP"
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echo "If that's not the case, just ignore this and leave the next field blank"
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read -p "External IP: " -e USEREXTERNALIP
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if [[ "$USEREXTERNALIP" != "" ]]; then
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IP=$USEREXTERNALIP
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fi
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fi
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# client-common.txt is created so we have a template to add further users later
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echo "client
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dev tun
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proto $PROTOCOL
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sndbuf 0
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rcvbuf 0
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remote $IP $PORT
|
|
resolv-retry infinite
|
|
nobind
|
|
persist-key
|
|
persist-tun
|
|
remote-cert-tls server
|
|
auth SHA512
|
|
cipher AES-256-CBC
|
|
comp-lzo
|
|
setenv opt block-outside-dns
|
|
key-direction 1
|
|
verb 3" > /etc/openvpn/client-common.txt
|
|
# Generates the custom client.ovpn
|
|
newclient "$CLIENT"
|
|
echo ""
|
|
echo "Finished!"
|
|
echo ""
|
|
echo "Your client configuration is available at" ~/"$CLIENT.ovpn"
|
|
echo "If you want to add more clients, you simply need to run this script again!"
|
|
fi
|