diff --git a/openvpn-install.sh b/openvpn-install.sh
index 90aeb43..e73c8c4 100644
--- a/openvpn-install.sh
+++ b/openvpn-install.sh
@@ -102,27 +102,27 @@ if [[ ! -e /etc/openvpn/server/server.conf ]]; then
 	clear
 	echo 'Welcome to this OpenVPN road warrior installer!'
 	# If system has a single IPv4, it is selected automatically. Else, ask the user
-	if [[ $(ip -4 addr | grep inet | grep -vEc '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}') -eq 1 ]]; then
-		ip=$(ip -4 addr | grep inet | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}')
+	if [[ $(ip -4 addr | grep inet | grep -vEc '127(\.[0-9]{1,3}){3}') -eq 1 ]]; then
+		ip=$(ip -4 addr | grep inet | grep -vE '127(\.[0-9]{1,3}){3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}(\.[0-9]{1,3}){3}')
 	else
-		number_of_ip=$(ip -4 addr | grep inet | grep -vEc '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}')
+		number_of_ip=$(ip -4 addr | grep inet | grep -vEc '127(\.[0-9]{1,3}){3}')
 		echo
 		echo "Which IPv4 address should be used?"
-		ip -4 addr | grep inet | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | nl -s ') '
+		ip -4 addr | grep inet | grep -vE '127(\.[0-9]{1,3}){3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}(\.[0-9]{1,3}){3}' | nl -s ') '
 		read -p "IPv4 address [1]: " ip_number
 		until [[ -z "$ip_number" || "$ip_number" =~ ^[0-9]+$ && "$ip_number" -le "$number_of_ip" ]]; do
 			echo "$ip_number: invalid selection."
 			read -p "IPv4 address [1]: " ip_number
 		done
 		[[ -z "$ip_number" ]] && ip_number="1"
-		ip=$(ip -4 addr | grep inet | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | sed -n "$ip_number"p)
+		ip=$(ip -4 addr | grep inet | grep -vE '127(\.[0-9]{1,3}){3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}(\.[0-9]{1,3}){3}' | sed -n "$ip_number"p)
 	fi
 	# 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?"
 		# Get public IP and sanitize with grep
-		get_public_ip=$(grep -m 1 -oE '^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$' <<< "$(wget -T 10 -t 1 -4qO- "http://ip1.dynupdate.no-ip.com/" || curl -m 10 -4Ls "http://ip1.dynupdate.no-ip.com/")")
+		get_public_ip=$(grep -m 1 -oE '^[0-9]{1,3}(\.[0-9]{1,3}){3}$' <<< "$(wget -T 10 -t 1 -4qO- "http://ip1.dynupdate.no-ip.com/" || curl -m 10 -4Ls "http://ip1.dynupdate.no-ip.com/")")
 		read -p "Public IPv4 address / hostname [$get_public_ip]: " public_ip
 		# If the checkip service is unavailable and user didn't provide input, ask again
 		until [[ -n "$get_public_ip" || -n "$public_ip" ]]; do
@@ -287,7 +287,7 @@ server 10.8.0.0 255.255.255.0" > /etc/openvpn/server/server.conf
 				resolv_conf="/etc/resolv.conf"
 			fi
 			# Obtain the resolvers from resolv.conf and use them for OpenVPN
-			grep -v '#' "$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 '#' "$resolv_conf" | grep nameserver | grep -E -o '[0-9]{1,3}(\.[0-9]{1,3}){3}' | while read line; do
 				echo "push \"dhcp-option DNS $line\"" >> /etc/openvpn/server/server.conf
 			done
 		;;