Merge branch 'master' into pass

LICENSE

@@ -1,6 +1,7 @@
-The MIT License (MIT)
+MIT License
 
-Copyright (c) 2016 Nyr, Angristan
+Copyright (c) 2013 Nyr
+Copyright (c) 2016 Angristan (Stanislas Lange)
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of
 this software and associated documentation files (the "Software"), to deal in

README.md

@@ -40,11 +40,11 @@ When OpenVPN is installed, you can run the script again, and you will get the ch
 
 This script is based on the great work of [Nyr and its contributors](https://github.com/Nyr/openvpn-install).
 
-I made it because I wanted to have a more secured OpenVPN out-of-the-box. It works like the original script, but is more focused on privacy and espicially better encryption. Nyr's original script uses mainly default parameters regarding encryption, and some of them are unsecure. See [#encryption](#encryption).
+I made it because I wanted to have a more secured OpenVPN out-of-the-box. It works like the original script, but is more focused on privacy and especially better encryption. Nyr's original script uses mainly default parameters regarding encryption, and some of them are insecure. See [#encryption](#encryption).
 
 Also, Nyr and myself clearly have not the same point of view regarding this script, that's why it's a fork.
 
-The only drawback is that you need to use a recent version of OpenVPN, because some parameters that requires TLS 1.2 are only availble since OpenVPN 2.3.3. Therefore I restrain the compatibility of this script to a few but widely used GNU/Linux distributions, to get a recent version of OpenVPN from trusted third-party repositories, if needed. That is not a complete drawback tough, because it means that you can have the latest version with all the new features and security fixes. See [compatibilty](#compatibility).
+The only drawback is that you need to use a recent version of OpenVPN, because some parameters that requires TLS 1.2 are only available since OpenVPN 2.3.3. Therefore I restrain the compatibility of this script to a few but widely used GNU/Linux distributions, to get a recent version of OpenVPN from trusted third-party repositories, if needed. That is not a complete drawback tough, because it means that you can have the latest version with all the new features and security fixes. See [compatibility](#compatibility).
 
 On the client-side, it's less problematic, but if you want to use an OpenVPN server installed with this script with an old client (\<2.3.3), it won't work. However I don't see why you would use an outdated client.
 
@@ -59,11 +59,10 @@ The script is made to work on these OS and architectures :
 - **Debian 7** (i386, amd64)
 - **Debian 8** (i386, amd64)
 - **Debian 9** (i386, amd64, armhf, arm64)
-- **Ubuntu 12.04 LTS** (i386, amd64)
 - **Ubuntu 14.04 LTS** (i386, amd64)
-- **Ubuntu 16.04 LTS** (i386, amd64)
+- **Ubuntu 16.04 LTS** (i386, amd64, armhf)
-- **Ubuntu 16.10** (i386, amd64, armhf, arm64)
+- **Ubuntu 17.10** (i386, amd64, armhf, arm64)
-- **Ubuntu 17.04** (i386, amd64, armhf, arm64)
+- **Ubuntu 18.04 LTS** (i386, amd64, armhf, arm64)
 - **Fedora 25** (amd64)
 - **Fedora 26** (amd64)
 - **Fedora 27** (amd64)
@@ -99,6 +98,7 @@ The script will ask you which DNS resolvers you want to use when connected to th
 Here are the possibilities :
 
 - Current system resolvers, those that are in `/etc/resolv.conf`
+- [Cloudflare](https://1.1.1.1/), recommended, fastest resolvers available (Anycast servers)
 - [Quad9](https://www.quad9.net), recommended, security and privacy oriented, fast worldwide (Anycast servers)
 - [FDN's DNS Servers](http://www.fdn.fr/actions/dns/), recommended if you're in western europe (France)
 - [DNS.WATCH DNS Servers](https://dns.watch/index), recommended if you're in western europe (Germany)
@@ -150,7 +150,7 @@ It also supports SHA1 and MD5, which are unsafe, and all the SHA2 family. I didn
 
 ### Data channel's cipher
 
-By default, OpenVPN uses `BF-CBC` as the data channel cipher. Blowfish is an old (1993) an weak alogorithm. What's *funny* is that even the official OpenVPN documentation admits it.
+By default, OpenVPN uses `BF-CBC` as the data channel cipher. Blowfish is an old (1993) and weak alogorithm. What's *funny* is that even the official OpenVPN documentation admits it.
 
 >The default is BF-CBC, an abbreviation for Blowfish in Cipher Block Chaining mode.
 Using BF-CBC is no longer recommended, because of its 64-bit block size. This small block size allows attacks based on collisions, as demonstrated by SWEET32. See https://community.openvpn.net/openvpn/wiki/SWEET32 for details.
@@ -187,7 +187,7 @@ The [SWEET32 vulnerability page](https://community.openvpn.net/openvpn/wiki/SWEE
 
 Indeed, AES is today's standard. It's the fastest and more secure cipher available today. [SEED](https://en.wikipedia.org/wiki/SEED) and [Camellia](https://en.wikipedia.org/wiki/Camellia_(cipher)) are not vulnerable to date but are slower than AES and relatively less trusted.
 
-As they have not any proven vulnerabilities, I decided to give the user the choice to use them, though I don't see any particular reason to this day to use it. Maybe someday if AES happens to be broken. Here is an exemple about [why Camellia is good, but AES is better and should be used](http://crypto.stackexchange.com/questions/476/why-does-nobody-use-or-break-the-camellia-cipher/477#477).
+As they have not any proven vulnerabilities, I decided to give the user the choice to use them, though I don't see any particular reason to this day to use it. Maybe someday if AES happens to be broken. Here is an example about [why Camellia is good, but AES is better and should be used](http://crypto.stackexchange.com/questions/476/why-does-nobody-use-or-break-the-camellia-cipher/477#477).
 
 Currently AES is only available in its CBC mode, which is weaker than GCM.
 
@@ -215,7 +215,7 @@ Thus, the best data channel cipher currently available in OpenVPN is `AES-128-CB
 
 ### Control channel's cipher
 
-According to the [Hardening](https://community.openvpn.net/openvpn/wiki/Hardening#Useof--tls-cipher) page of the OpenVPN wiki, TLS 1.2 is not supported by OpenVPN <2.3.3, so it uses a TLS 1.0 cipher by default, which is unsecure.
+According to the [Hardening](https://community.openvpn.net/openvpn/wiki/Hardening#Useof--tls-cipher) page of the OpenVPN wiki, TLS 1.2 is not supported by OpenVPN <2.3.3, so it uses a TLS 1.0 cipher by default, which is insecure.
 
 > The following are TLSv1.2 DHE + RSA choices, requiring a compatible peer running at least OpenVPN 2.3.3:
 - TLS-DHE-RSA-WITH-AES-256-GCM-SHA384
@@ -231,7 +231,7 @@ Thus, I have chosen `TLS-DHE-RSA-WITH-AES-128-GCM-SHA256` as the control channel
 
 OpenVPN uses a 2048 bits DH key [by default](https://github.com/OpenVPN/easy-rsa/blob/master/easyrsa3/vars.example#L97).
 
-2048 bits is OK, but both [NSA](https://cryptome.org/2016/01/CNSA-Suite-and-Quantum-Computing-FAQ.pdf) and [ANSSI](https://www.ssi.gouv.fr/uploads/2015/01/RGS_v-2-0_B1.pdf) recommend at least a 3072 bits for a future-proof key. Like RSA, the size of the key will have an impact on speed, I leave the choice to use a 2048, 3072 or 4096 bits key. 4096 bits is what's most used and recommened today, but 3072 bits is still good.
+2048 bits is OK, but both [NSA](https://cryptome.org/2016/01/CNSA-Suite-and-Quantum-Computing-FAQ.pdf) and [ANSSI](https://www.ssi.gouv.fr/uploads/2015/01/RGS_v-2-0_B1.pdf) recommend at least a 3072 bits for a future-proof key. Like RSA, the size of the key will have an impact on speed, I leave the choice to use a 2048, 3072 or 4096 bits key. 4096 bits is what's most used and recommended today, but 3072 bits is still good.
 
 In OpenVPN 2.4, we will be able to use ECDH key. It uses elliptic curves instead of prime numbers' factorization for a reduced key size and calculation time, thus it's faster and more secure.
 
@@ -256,6 +256,14 @@ SHA-1 is not safe anymore, so I use SHA-256 which is safe and widely used.
 
 TLS-Auth is not enabled by default by OpenVPN, but it is in this script.
 
+## Check for DNS leaks
+
+Go to [dnsleaktest.com](https://dnsleaktest.com/) or [ipleak.net](https://ipleak.net/) with your browser. Only your server's IP should show up.
+
+## Say thanks
+
+You can [say thanks](https://saythanks.io/to/Angristan) if you want!
+
 ## Credits & Licence
 
 Thanks to the [contributors](https://github.com/Angristan/OpenVPN-install/graphs/contributors) and of course Nyr's orginal work.

openvpn-install.sh

@@ -4,16 +4,19 @@
 # https://github.com/Angristan/OpenVPN-install
 
 
+# Verify root
 if [[ "$EUID" -ne 0 ]]; then
 	echo "Sorry, you need to run this as root"
 	exit 1
 fi
 
+# Verify tun
 if [[ ! -e /dev/net/tun ]]; then
 	echo "TUN is not available"
 	exit 2
 fi
 
+# Check if CentOS 5
 if grep -qs "CentOS release 5" "/etc/redhat-release"; then
 	echo "CentOS 5 is too old and not supported"
 	exit 3
@@ -22,10 +25,10 @@ fi
 if [[ -e /etc/debian_version ]]; then
 	OS="debian"
 	# Getting the version number, to verify that a recent version of OpenVPN is available
-	VERSION_ID=$(cat /etc/os-release | grep "VERSION_ID")
+	VERSION_ID=$(grep "VERSION_ID" /etc/os-release)
 	IPTABLES='/etc/iptables/iptables.rules'
 	SYSCTL='/etc/sysctl.conf'
-	if [[ "$VERSION_ID" != 'VERSION_ID="7"' ]] && [[ "$VERSION_ID" != 'VERSION_ID="8"' ]] && [[ "$VERSION_ID" != 'VERSION_ID="9"' ]] && [[ "$VERSION_ID" != 'VERSION_ID="12.04"' ]] && [[ "$VERSION_ID" != 'VERSION_ID="14.04"' ]] && [[ "$VERSION_ID" != 'VERSION_ID="16.04"' ]] && [[ "$VERSION_ID" != 'VERSION_ID="16.10"' ]] && [[ "$VERSION_ID" != 'VERSION_ID="17.04"' ]]; then
+	if [[ "$VERSION_ID" != 'VERSION_ID="7"' ]] && [[ "$VERSION_ID" != 'VERSION_ID="8"' ]] && [[ "$VERSION_ID" != 'VERSION_ID="9"' ]] && [[ "$VERSION_ID" != 'VERSION_ID="14.04"' ]] && [[ "$VERSION_ID" != 'VERSION_ID="16.04"' ]] && [[ "$VERSION_ID" != 'VERSION_ID="17.10"' ]] && [[ "$VERSION_ID" != 'VERSION_ID="18.04"' ]]; then
 		echo "Your version of Debian/Ubuntu is not supported."
 		echo "I can't install a recent version of OpenVPN on your system."
 		echo ""
@@ -33,14 +36,18 @@ if [[ -e /etc/debian_version ]]; then
 		echo "then you can continue, a recent version of OpenVPN is available on these."
 		echo "Keep in mind they are not supported, though."
 		while [[ $CONTINUE != "y" && $CONTINUE != "n" ]]; do
-			read -p "Continue ? [y/n]: " -e CONTINUE
+			read -rp "Continue ? [y/n]: " -e CONTINUE
 		done
 		if [[ "$CONTINUE" = "n" ]]; then
 			echo "Ok, bye !"
 			exit 4
 		fi
 	fi
-elif [[ -e /etc/centos-release || -e /etc/redhat-release || -e /etc/system-release && ! -e /etc/fedora-release ]]; then
+elif [[ -e /etc/fedora-release ]]; then
+	OS=fedora
+	IPTABLES='/etc/iptables/iptables.rules'
+	SYSCTL='/etc/sysctl.d/openvpn.conf'
+elif [[ -e /etc/centos-release || -e /etc/redhat-release || -e /etc/system-release ]]; then
 	OS=centos
 	IPTABLES='/etc/iptables/iptables.rules'
 	SYSCTL='/etc/sysctl.conf'
@@ -48,10 +55,6 @@ elif [[ -e /etc/arch-release ]]; then
 	OS=arch
 	IPTABLES='/etc/iptables/iptables.rules'
 	SYSCTL='/etc/sysctl.d/openvpn.conf'
-elif [[ -e /etc/fedora-release ]]; then
-	OS=fedora
-	IPTABLES='/etc/iptables/iptables.rules'
-	SYSCTL='/etc/sysctl.d/openvpn.conf'
 else
 	echo "Looks like you aren't running this installer on a Debian, Ubuntu, CentOS or ArchLinux system"
 	exit 4
@@ -59,37 +62,35 @@ fi
 
 newclient () {
 	# Where to write the custom client.ovpn?
-	if [ -e /home/$1 ]; then  # if $1 is a user name
+	if [ -e "/home/$1" ]; then  # if $1 is a user name
 		homeDir="/home/$1"
-	elif [ ${SUDO_USER} ]; then   # if not, use SUDO_USER
+	elif [ "${SUDO_USER}" ]; then   # if not, use SUDO_USER
 		homeDir="/home/${SUDO_USER}"
 	else  # if not SUDO_USER, use /root
 		homeDir="/root"
 	fi
 	# Generates the custom client.ovpn
-	cp /etc/openvpn/client-template.txt $homeDir/$1.ovpn
+	cp /etc/openvpn/client-template.txt "$homeDir/$1.ovpn"
-	echo "<ca>" >> $homeDir/$1.ovpn
+	{
-	cat /etc/openvpn/easy-rsa/pki/ca.crt >> $homeDir/$1.ovpn
+		echo "<ca>"
-	echo "</ca>" >> $homeDir/$1.ovpn
+		cat "/etc/openvpn/easy-rsa/pki/ca.crt"
-	echo "<cert>" >> $homeDir/$1.ovpn
+		echo "</ca>"
-	cat /etc/openvpn/easy-rsa/pki/issued/$1.crt >> $homeDir/$1.ovpn
+
-	echo "</cert>" >> $homeDir/$1.ovpn
+		echo "<cert>"
-	echo "<key>" >> $homeDir/$1.ovpn
+		cat "/etc/openvpn/easy-rsa/pki/issued/$1.crt"
-	cat /etc/openvpn/easy-rsa/pki/private/$1.key >> $homeDir/$1.ovpn
+		echo "</cert>"
-	echo "</key>" >> $homeDir/$1.ovpn
+
-	echo "key-direction 1" >> $homeDir/$1.ovpn
+		echo "<key>"
-	echo "<tls-auth>" >> $homeDir/$1.ovpn
+		cat "/etc/openvpn/easy-rsa/pki/private/$1.key"
-	cat /etc/openvpn/tls-auth.key >> $homeDir/$1.ovpn
+		echo "</key>"
-	echo "</tls-auth>" >> $homeDir/$1.ovpn
+		echo "key-direction 1"
+
+		echo "<tls-auth>"
+		cat "/etc/openvpn/tls-auth.key"
+		echo "</tls-auth>"
+	} >> "$homeDir/$1.ovpn"
 }
 
-# Try to get our IP from the system and fallback to the Internet.
-# I do this to make the script compatible with NATed servers (LowEndSpirit/Scaleway)
-# and to avoid getting an IPv6.
-IP=$(ip addr | grep 'inet' | grep -v inet6 | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | grep -o -E '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | head -1)
-if [[ "$IP" = "" ]]; then
-	IP=$(wget -qO- ipv4.icanhazip.com)
-fi
 # Get Internet network interface with default route
 NIC=$(ip -4 route ls | grep default | grep -Po '(?<=dev )(\S+)' | head -1)
 
@@ -101,12 +102,14 @@ if [[ -e /etc/openvpn/server.conf ]]; then
 		echo ""
 		echo "Looks like OpenVPN is already installed"
 		echo ""
+
 		echo "What do you want to do?"
 		echo "   1) Add a cert for a new user"
 		echo "   2) Revoke existing user cert"
 		echo "   3) Remove OpenVPN"
 		echo "   4) Exit"
-		read -p "Select an option [1-4]: " option
+		read -rp "Select an option [1-4]: " option
+
 		case $option in
 			1)
 			echo ""
@@ -120,8 +123,9 @@ if [[ -e /etc/openvpn/server.conf ]]; then
 			echo ""
 			echo "Tell me a name for the client cert"
 			echo "Please, use one word only, no special characters"
-			read -p "Client name: " -e -i client CLIENT
+
-			cd /etc/openvpn/easy-rsa/
+			read -rp "Client name: " -e -i newclient CLIENT
+			cd /etc/openvpn/easy-rsa/ || return
 			case $pass in
 				1)
 				./easyrsa build-client-full $CLIENT nopass
@@ -131,8 +135,10 @@ if [[ -e /etc/openvpn/server.conf ]]; then
 				./easyrsa build-client-full $CLIENT
 				;;
 			esac
+
 			# Generates the custom client.ovpn
 			newclient "$CLIENT"
+
 			echo ""
 			echo "Client $CLIENT added, certs available at $homeDir/$CLIENT.ovpn"
 			exit
@@ -144,24 +150,29 @@ if [[ -e /etc/openvpn/server.conf ]]; then
 				echo "You have no existing clients!"
 				exit 5
 			fi
+
 			echo ""
 			echo "Select the existing client certificate you want to revoke"
 			tail -n +2 /etc/openvpn/easy-rsa/pki/index.txt | grep "^V" | cut -d '=' -f 2 | nl -s ') '
 			if [[ "$NUMBEROFCLIENTS" = '1' ]]; then
-				read -p "Select one client [1]: " CLIENTNUMBER
+				read -rp "Select one client [1]: " CLIENTNUMBER
 			else
-				read -p "Select one client [1-$NUMBEROFCLIENTS]: " CLIENTNUMBER
+				read -rp "Select one client [1-$NUMBEROFCLIENTS]: " CLIENTNUMBER
 			fi
+
 			CLIENT=$(tail -n +2 /etc/openvpn/easy-rsa/pki/index.txt | grep "^V" | cut -d '=' -f 2 | sed -n "$CLIENTNUMBER"p)
-			cd /etc/openvpn/easy-rsa/
+			cd /etc/openvpn/easy-rsa/ || return
 			./easyrsa --batch revoke $CLIENT
 			EASYRSA_CRL_DAYS=3650 ./easyrsa gen-crl
-			rm -rf pki/reqs/$CLIENT.req
+			rm -f pki/reqs/$CLIENT.req
-			rm -rf pki/private/$CLIENT.key
+			rm -f pki/private/$CLIENT.key
-			rm -rf pki/issued/$CLIENT.crt
+			rm -f pki/issued/$CLIENT.crt
-			rm -rf /etc/openvpn/crl.pem
+			rm -f /etc/openvpn/crl.pem
 			cp /etc/openvpn/easy-rsa/pki/crl.pem /etc/openvpn/crl.pem
 			chmod 644 /etc/openvpn/crl.pem
+			rm -f $(find /home -maxdepth 2 | grep $CLIENT.ovpn) 2>/dev/null
+			rm -f /root/$CLIENT.ovpn 2>/dev/null
+
 			echo ""
 			echo "Certificate for client $CLIENT revoked"
 			echo "Exiting..."
@@ -169,7 +180,7 @@ if [[ -e /etc/openvpn/server.conf ]]; then
 			;;
 			3)
 			echo ""
-			read -p "Do you really want to remove OpenVPN? [y/n]: " -e -i n REMOVE
+			read -rp "Do you really want to remove OpenVPN? [y/n]: " -e -i n REMOVE
 			if [[ "$REMOVE" = 'y' ]]; then
 				PORT=$(grep '^port ' /etc/openvpn/server.conf | cut -d " " -f 2)
 				if pgrep firewalld; then
@@ -204,6 +215,12 @@ if [[ -e /etc/openvpn/server.conf ]]; then
 				else
 					yum remove openvpn -y
 				fi
+				OVPNS=$(ls /etc/openvpn/easy-rsa/pki/issued | awk -F "." {'print $1'})
+				for i in $OVPNS
+				do
+				rm $(find /home -maxdepth 2 | grep $i.ovpn) 2>/dev/null
+				rm /root/$i.ovpn 2>/dev/null
+				done
 				rm -rf /etc/openvpn
 				rm -rf /usr/share/doc/openvpn*
 				echo ""
@@ -221,6 +238,7 @@ else
 	clear
 	echo "Welcome to the secure OpenVPN installer (github.com/Angristan/OpenVPN-install)"
 	echo ""
+
 	# OpenVPN setup and first user creation
 	echo "I need to ask you a few questions before starting the setup"
 	echo "You can leave the default options and just press enter if you are ok with them"
@@ -228,28 +246,59 @@ else
 	echo "I need to know the IPv4 address of the network interface you want OpenVPN listening to."
 	echo "If your server is running behind a NAT, (e.g. LowEndSpirit, Scaleway) leave the IP address as it is. (local/private IP)"
 	echo "Otherwise, it should be your public IPv4 address."
-	read -p "IP address: " -e -i $IP IP
+
+	# Autodetect IP address and pre-fill for the user
+	IP=$(ip addr | grep 'inet' | grep -v inet6 | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | grep -oE '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | head -1)
+	read -rp "IP address: " -e -i $IP IP
 	echo ""
 	echo "What port do you want for OpenVPN?"
-	read -p "Port: " -e -i 1194 PORT
+	echo "   1) Default: 1194"
+	echo "   2) Custom"
+	echo "   3) Random [49152-65535]"
+	until [[ "$PORT_CHOICE" =~ ^[1-3]$ ]]; do
+		read -p "Port choice [1-3]: " -e -i 1 PORT_CHOICE
+	done
+	case $PORT_CHOICE in
+		1)
+			PORT="1194"
+		;;
+		2)
+			until [[ "$PORT" =~ ^[0-9]+$ ]] && [ "$PORT" -ge 1 -a "$PORT" -le 65535 ]; do
+				read -p "Custom port [1-65535]: " -e -i 1194 PORT
+			done
+		;;
+		3)
+			# Generate random number within private ports range
+			PORT=$(shuf -i49152-65535 -n1)
+			echo "Random Port: $PORT"
+		;;
+	esac
+
+	# If $IP is a private IP address, the server must be behind NAT
+	if echo "$IP" | grep -qE '^(10\.|172\.1[6789]\.|172\.2[0-9]\.|172\.3[01]\.|192\.168)'; then
+		echo ""
+		echo "This server is behind NAT. What is the public IPv4 address or hostname?"
+		read -rp "Public IP address / hostname: " -e PUBLICIP
+	fi
 	echo ""
 	echo "What protocol do you want for OpenVPN?"
 	echo "Unless UDP is blocked, you should not use TCP (unnecessarily slower)"
-	while [[ $PROTOCOL != "UDP" && $PROTOCOL != "TCP" ]]; do
+	until [[ "$PROTOCOL" == "UDP" || "$PROTOCOL" == "TCP" ]]; do
-		read -p "Protocol [UDP/TCP]: " -e -i UDP PROTOCOL
+		read -rp "Protocol [UDP/TCP]: " -e -i UDP PROTOCOL
 	done
 	echo ""
 	echo "What DNS do you want to use with the VPN?"
 	echo "   1) Current system resolvers (from /etc/resolv.conf)"
-	echo "   2) Quad9 (Anycast: worldwide)"
+	echo "   2) Cloudflare (Anycast: worldwide)"
-	echo "   3) FDN (France)"
+	echo "   3) Quad9 (Anycast: worldwide)"
-	echo "   4) DNS.WATCH (Germany)"
+	echo "   4) FDN (France)"
-	echo "   5) OpenDNS (Anycast: worldwide)"
+	echo "   5) DNS.WATCH (Germany)"
-	echo "   6) Google (Anycast: worldwide)"
+	echo "   6) OpenDNS (Anycast: worldwide)"
-	echo "   7) Yandex Basic (Russia)"
+	echo "   7) Google (Anycast: worldwide)"
-	echo "   8) AdGuard DNS (Russia)"
+	echo "   8) Yandex Basic (Russia)"
-	while [[ $DNS != "1" && $DNS != "2" && $DNS != "3" && $DNS != "4" && $DNS != "5" && $DNS != "6" && $DNS != "7" && $DNS != "8" ]]; do
+	echo "   9) AdGuard DNS (Russia)"
-		read -p "DNS [1-8]: " -e -i 1 DNS
+	until [[ "$DNS" =~ ^[0-9]+$ ]] && [ "$DNS" -ge 1 -a "$DNS" -le 9 ]; do
+		read -rp "DNS [1-9]: " -e -i 1 DNS
 	done
 	echo ""
 	echo "See https://github.com/Angristan/OpenVPN-install#encryption to learn more about "
@@ -267,8 +316,8 @@ else
 	echo "   5) CAMELLIA-192-CBC"
 	echo "   6) CAMELLIA-256-CBC"
 	echo "   7) SEED-CBC"
-	while [[ $CIPHER != "1" && $CIPHER != "2" && $CIPHER != "3" && $CIPHER != "4" && $CIPHER != "5" && $CIPHER != "6" && $CIPHER != "7" ]]; do
+	until [[ "$CIPHER" =~ ^[0-9]+$ ]] && [ "$CIPHER" -ge 1 -a "$CIPHER" -le 7 ]; do
-		read -p "Cipher [1-7]: " -e -i 1 CIPHER
+		read -rp "Cipher [1-7]: " -e -i 1 CIPHER
 	done
 	case $CIPHER in
 		1)
@@ -298,8 +347,8 @@ else
 	echo "   1) 2048 bits (fastest)"
 	echo "   2) 3072 bits (recommended, best compromise)"
 	echo "   3) 4096 bits (most secure)"
-	while [[ $DH_KEY_SIZE != "1" && $DH_KEY_SIZE != "2" && $DH_KEY_SIZE != "3" ]]; do
+	until [[ "$DH_KEY_SIZE" =~ ^[0-9]+$ ]] && [ "$DH_KEY_SIZE" -ge 1 -a "$DH_KEY_SIZE" -le 3 ]; do
-		read -p "DH key size [1-3]: " -e -i 2 DH_KEY_SIZE
+		read -rp "DH key size [1-3]: " -e -i 2 DH_KEY_SIZE
 	done
 	case $DH_KEY_SIZE in
 		1)
@@ -317,8 +366,8 @@ else
 	echo "   1) 2048 bits (fastest)"
 	echo "   2) 3072 bits (recommended, best compromise)"
 	echo "   3) 4096 bits (most secure)"
-	while [[ $RSA_KEY_SIZE != "1" && $RSA_KEY_SIZE != "2" && $RSA_KEY_SIZE != "3" ]]; do
+	until [[ "$RSA_KEY_SIZE" =~ ^[0-9]+$ ]] && [ "$RSA_KEY_SIZE" -ge 1 -a "$RSA_KEY_SIZE" -le 3 ]; do
-		read -p "RSA key size [1-3]: " -e -i 2 RSA_KEY_SIZE
+		read -rp "RSA key size [1-3]: " -e -i 2 RSA_KEY_SIZE
 	done
 	case $RSA_KEY_SIZE in
 		1)
@@ -343,14 +392,16 @@ else
 	echo "Finally, tell me a name for the client certificate and configuration"
 	while [[ $CLIENT = "" ]]; do
 		echo "Please, use one word only, no special characters"
-		read -p "Client name: " -e -i client CLIENT
+		read -rp "Client name: " -e -i client CLIENT
+		# Remove special characters
+		CLIENT=$(echo $CLIENT | tr -dc '[:alnum:]\n\r')
 	done
 	echo ""
 	echo "Okay, that was all I needed. We are ready to setup your OpenVPN server now"
 	read -n1 -r -p "Press any key to continue..."
 
 	if [[ "$OS" = 'debian' ]]; then
-		apt-get install ca-certificates -y
+		apt-get install ca-certificates gnupg -y
 		# We add the OpenVPN repo to get the latest version.
 		# Debian 7
 		if [[ "$VERSION_ID" = 'VERSION_ID="7"' ]]; then
@@ -364,12 +415,6 @@ else
 			wget -O - https://swupdate.openvpn.net/repos/repo-public.gpg | apt-key add -
 			apt update
 		fi
-		# Ubuntu 12.04
-		if [[ "$VERSION_ID" = 'VERSION_ID="12.04"' ]]; then
-			echo "deb http://build.openvpn.net/debian/openvpn/stable precise main" > /etc/apt/sources.list.d/openvpn.list
-			wget -O - https://swupdate.openvpn.net/repos/repo-public.gpg | apt-key add -
-			apt-get update
-		fi
 		# Ubuntu 14.04
 		if [[ "$VERSION_ID" = 'VERSION_ID="14.04"' ]]; then
 			echo "deb http://build.openvpn.net/debian/openvpn/stable trusty main" > /etc/apt/sources.list.d/openvpn.list
@@ -457,8 +502,8 @@ WantedBy=multi-user.target" > /etc/systemd/system/iptables.service
 		echo "Not doing that could cause problems between dependencies, or missing files in repositories."
 		echo ""
 		echo "Continuing will update your installed packages and install needed ones."
-		while [[ $CONTINUE != "y" && $CONTINUE != "n" ]]; do
+		until [[ $CONTINUE == "y" || $CONTINUE == "n" ]]; do
-			read -p "Continue ? [y/n]: " -e -i y CONTINUE
+			read -rp "Continue ? [y/n]: " -e -i y CONTINUE
 		done
 		if [[ "$CONTINUE" = "n" ]]; then
 			echo "Ok, bye !"
@@ -491,11 +536,11 @@ WantedBy=multi-user.target" > /etc/systemd/system/iptables.service
 	mv ~/EasyRSA-3.0.4/ /etc/openvpn/
 	mv /etc/openvpn/EasyRSA-3.0.4/ /etc/openvpn/easy-rsa/
 	chown -R root:root /etc/openvpn/easy-rsa/
-	rm -rf ~/EasyRSA-3.0.4.tgz
+	rm -f ~/EasyRSA-3.0.4.tgz
-	cd /etc/openvpn/easy-rsa/
+	cd /etc/openvpn/easy-rsa/ || return
 	# Generate a random, alphanumeric identifier of 16 characters for CN and one for server name
-	SERVER_CN="cn_$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 16 | head -n 1)"
+	SERVER_CN="cn_$(tr -dc 'a-zA-Z0-9' < /dev/urandom | fold -w 16 | head -n 1)"
-	SERVER_NAME="server_$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 16 | head -n 1)"
+	SERVER_NAME="server_$(tr -dc 'a-zA-Z0-9' < /dev/urandom | fold -w 16 | head -n 1)"
 	echo "set_var EASYRSA_KEY_SIZE $RSA_KEY_SIZE" > vars
 	echo "set_var EASYRSA_REQ_CN $SERVER_CN" >> vars
 	# Create the PKI, set up the CA, the DH params and the server + client certificates
@@ -522,11 +567,7 @@ WantedBy=multi-user.target" > /etc/systemd/system/iptables.service
 
 	# Generate server.conf
 	echo "port $PORT" > /etc/openvpn/server.conf
-	if [[ "$PROTOCOL" = 'UDP' ]]; then
+	echo "proto $(echo $PROTOCOL | tr '[:upper:]' '[:lower:]')" >> /etc/openvpn/server.conf
-		echo "proto udp" >> /etc/openvpn/server.conf
-	elif [[ "$PROTOCOL" = 'TCP' ]]; then
-		echo "proto tcp" >> /etc/openvpn/server.conf
-	fi
 	echo "dev tun
 user nobody
 group $NOGROUP
@@ -539,35 +580,47 @@ ifconfig-pool-persist ipp.txt" >> /etc/openvpn/server.conf
 	# DNS resolvers
 	case $DNS in
 		1)
+		# Locate the proper resolv.conf
+		# Needed for systems running systemd-resolved
+		if grep -q "127.0.0.53" "/etc/resolv.conf"; then
+			RESOLVCONF='/run/systemd/resolve/resolv.conf'
+		else
+			RESOLVCONF='/etc/resolv.conf'
+		fi
 		# Obtain the resolvers from resolv.conf and use them for OpenVPN
-		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
+		grep -v '#' $RESOLVCONF | grep 'nameserver' | grep -E -o '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | while read -r line; do
 			echo "push \"dhcp-option DNS $line\"" >> /etc/openvpn/server.conf
 		done
 		;;
-		2) #Quad9
+		2) # Cloudflare
-		echo 'push "dhcp-option DNS 9.9.9.9"' >> /etc/openvpn/server.conf
+		echo 'push "dhcp-option DNS 1.0.0.1"' >> /etc/openvpn/server.conf
+		echo 'push "dhcp-option DNS 1.1.1.1"' >> /etc/openvpn/server.conf	
 		;;
-		3) #FDN
+		3) # Quad9
+		echo 'push "dhcp-option DNS 9.9.9.9"' >> /etc/openvpn/server.conf
+		echo 'push "dhcp-option DNS 149.112.112.112"' >> /etc/openvpn/server.conf
+		;;
+		4) # FDN
 		echo 'push "dhcp-option DNS 80.67.169.40"' >> /etc/openvpn/server.conf
 		echo 'push "dhcp-option DNS 80.67.169.12"' >> /etc/openvpn/server.conf
 		;;
-		4) #DNS.WATCH
+		5) # DNS.WATCH
 		echo 'push "dhcp-option DNS 84.200.69.80"' >> /etc/openvpn/server.conf
 		echo 'push "dhcp-option DNS 84.200.70.40"' >> /etc/openvpn/server.conf
 		;;
-		5) #OpenDNS
+		6) # OpenDNS
 		echo 'push "dhcp-option DNS 208.67.222.222"' >> /etc/openvpn/server.conf
 		echo 'push "dhcp-option DNS 208.67.220.220"' >> /etc/openvpn/server.conf
 		;;
-		6) #Google
+		7) # Google
 		echo 'push "dhcp-option DNS 8.8.8.8"' >> /etc/openvpn/server.conf
 		echo 'push "dhcp-option DNS 8.8.4.4"' >> /etc/openvpn/server.conf
 		;;
-		7) #Yandex Basic
+		8) # Yandex Basic
 		echo 'push "dhcp-option DNS 77.88.8.8"' >> /etc/openvpn/server.conf
 		echo 'push "dhcp-option DNS 77.88.8.1"' >> /etc/openvpn/server.conf
 		;;
-		8) #AdGuard DNS
+		9) # AdGuard DNS
 		echo 'push "dhcp-option DNS 176.103.130.130"' >> /etc/openvpn/server.conf
 		echo 'push "dhcp-option DNS 176.103.130.131"' >> /etc/openvpn/server.conf
 		;;
@@ -597,12 +650,16 @@ verb 3" >> /etc/openvpn/server.conf
 	if ! grep -q "\<net.ipv4.ip_forward\>" $SYSCTL; then
 		echo 'net.ipv4.ip_forward=1' >> $SYSCTL
 	fi
+
 	# Avoid an unneeded reboot
 	echo 1 > /proc/sys/net/ipv4/ip_forward
+
 	# Set NAT for the VPN subnet
 	iptables -t nat -A POSTROUTING -o $NIC -s 10.8.0.0/24 -j MASQUERADE
+
 	# Save persitent iptables rules
 	iptables-save > $IPTABLES
+
 	if pgrep firewalld; then
 		# We don't use --add-service=openvpn because that would only work with
 		# the default port. Using both permanent and not permanent rules to
@@ -617,6 +674,7 @@ verb 3" >> /etc/openvpn/server.conf
 		firewall-cmd --zone=trusted --add-source=10.8.0.0/24
 		firewall-cmd --permanent --zone=trusted --add-source=10.8.0.0/24
 	fi
+
 	if iptables -L -n | grep -qE 'REJECT|DROP'; then
 		# If iptables has at least one REJECT rule, we asume this is needed.
 		# Not the best approach but I can't think of other and this shouldn't
@@ -631,6 +689,7 @@ verb 3" >> /etc/openvpn/server.conf
 		# Save persitent OpenVPN rules
 		iptables-save > $IPTABLES
 	fi
+
 	# If SELinux is enabled and a custom port was selected, we need this
 	if hash sestatus 2>/dev/null; then
 		if sestatus | grep "Current mode" | grep -qs "enforcing"; then
@@ -647,6 +706,7 @@ verb 3" >> /etc/openvpn/server.conf
 			fi
 		fi
 	fi
+
 	# And finally, restart OpenVPN
 	if [[ "$OS" = 'debian' ]]; then
 		# Little hack to check for systemd
@@ -679,20 +739,12 @@ verb 3" >> /etc/openvpn/server.conf
 			chkconfig openvpn on
 		fi
 	fi
-	# Try to detect a NATed connection and ask about it to potential LowEndSpirit/Scaleway users
+
-	EXTERNALIP=$(wget -qO- ipv4.icanhazip.com)
+	# If the server is behind a NAT, use the correct IP address
-	if [[ "$IP" != "$EXTERNALIP" ]]; then
+	if [[ "$PUBLICIP" != "" ]]; then
-		echo ""
+		IP=$PUBLICIP
-		echo "Looks like your server is behind a NAT!"
-		echo ""
-        echo "If your server is NATed (e.g. LowEndSpirit, Scaleway, or behind a router),"
-        echo "then I need to know the address that can be used to access it from outside."
-        echo "If that's not the case, just ignore this and leave the next field blank"
-        read -p "External IP or domain name: " -e USEREXTERNALIP
-		if [[ "$USEREXTERNALIP" != "" ]]; then
-			IP=$USEREXTERNALIP
-		fi
 	fi
+	
 	# client-template.txt is created so we have a template to add further users later
 	echo "client" > /etc/openvpn/client-template.txt
 	if [[ "$PROTOCOL" = 'UDP' ]]; then