From b58057681495056a7e5bfe09282dc7b3dc0b5ba6 Mon Sep 17 00:00:00 2001 From: Nyr Date: Mon, 16 Apr 2018 17:53:48 +0200 Subject: [PATCH] [backport] Improve NAT detection Cleaner and better: - Not relying in an external service - Avoids a false positive when the server has multiple public IPv4 addresses and the user selects one which is not the default gateway --- openvpn-install.sh | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/openvpn-install.sh b/openvpn-install.sh index 699d9ac..cd3962c 100644 --- a/openvpn-install.sh +++ b/openvpn-install.sh @@ -219,6 +219,12 @@ else echo "" echo "What port do you want for OpenVPN?" read -p "Port: " -e -i 1194 PORT + # 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 -p "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)" @@ -649,19 +655,9 @@ 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=$(wget -qO- ipv4.icanhazip.com) - if [[ "$IP" != "$EXTERNALIP" ]]; then - echo "" - echo "Looks like your server is behind a NAT!" - echo "" - echo "If your server is NATed (e.g. LowEndSpirit, Scaleway, or behind a router)," - echo "then I need to know the address that can be used to access it from outside." - echo "If that's not the case, just ignore this and leave the next field blank" - read -p "External IP or domain name: " -e USEREXTERNALIP - if [[ "$USEREXTERNALIP" != "" ]]; then - IP=$USEREXTERNALIP - fi + # If the server is behind a NAT, use the correct IP address + if [[ "$PUBLICIP" != "" ]]; then + IP=$PUBLICIP fi # client-template.txt is created so we have a template to add further users later echo "client" > /etc/openvpn/client-template.txt