dont ask the user for the machine's IP address if we can be sure our guess is...

dont ask the user for the machine's IP address if we can be sure our guess is right (trust icanhazip to give us the right answer)

setup/functions.sh

@@ -70,20 +70,6 @@ function get_default_hostname {
 	printf '%s\n' "$1" # return this value
 }
 
-function get_default_publicip {
-	# Get the machine's public IP address. The machine might have
-	# an IP on a private network, but the IP address that we put
-	# into DNS must be one on the public Internet. Try a public
-	# API, but if that fails (maybe we don't have Internet access
-	# right now) then use the IP address that this machine knows
-	# itself as.
-	get_publicip_from_web_service 4 || get_default_privateip 4
-}
-
-function get_default_publicipv6 {
-	get_publicip_from_web_service 6 || get_default_privateip 6
-}
-
 function get_publicip_from_web_service {
 	# This seems to be the most reliable way to determine the
 	# machine's public IP address: asking a very nice web API

setup/start.sh

@@ -106,34 +106,62 @@ if [ -z "$PRIMARY_HOSTNAME" ]; then
 fi
 
 # If the machine is behind a NAT, inside a VM, etc., it may not know
-# its IP address on the public network / the Internet. We need to
-# confirm our best guess with the user.
+# its IP address on the public network / the Internet. Ask the Internet
+# and possibly confirm with user.
 if [ -z "$PUBLIC_IP" ]; then
-	if [ -z "$DEFAULT_PUBLIC_IP" ]; then
-		# set a default on first run
-		DEFAULT_PUBLIC_IP=`get_default_publicip`
+	# Ask the Internet.
+	GUESSED_IP=$(get_publicip_from_web_service 4)
+
+	# On the first run, if we got an answer from the Internet then don't
+	# ask the user.
+	if [[ -z "$DEFAULT_PUBLIC_IP" && ! -z "$GUESSED_IP" ]]; then
+		PUBLIC_IP=$GUESSED_IP
+
+	# Otherwise on the first run at least provide a default.
+	elif [[ -z "$DEFAULT_PUBLIC_IP" ]]; then
+		DEFAULT_PUBLIC_IP=$(get_default_privateip 4)
+
+	# On later runs, if the previous value matches the guessed value then
+	# don't ask the user either.
+	elif [ "$DEFAULT_PUBLIC_IP" == "$GUESSED_IP" ]; then
+		PUBLIC_IP=$GUESSED_IP
 	fi
 
-	echo
-	echo "Enter the public IP address of this machine, as given to you by your"
-	echo "ISP. We've guessed a value, but just backspace it if it's wrong."
-	echo
+	if [ -z "$PUBLIC_IP" ]; then
+		echo
+		echo "Enter the public IP address of this machine, as given to you by your ISP."
+		echo
 
-	read -e -i "$DEFAULT_PUBLIC_IP" -p "Public IP: " PUBLIC_IP
+		read -e -i "$DEFAULT_PUBLIC_IP" -p "Public IP: " PUBLIC_IP
+	fi
 fi
 
-# Same for IPv6.
+# Same for IPv6. But it's optional. Also, if it looks like the system
+# doesn't have an IPv6, don't ask for one.
 if [ -z "$PUBLIC_IPV6" ]; then
-	if [ -z "$DEFAULT_PUBLIC_IPV6" ]; then
-		# set a default on first run
-		DEFAULT_PUBLIC_IPV6=`get_default_publicipv6`
+	# Ask the Internet.
+	GUESSED_IP=$(get_publicip_from_web_service 6)
+	MATCHED=0
+	if [[ -z "$DEFAULT_PUBLIC_IPV6" && ! -z "$GUESSED_IP" ]]; then
+		PUBLIC_IPV6=$GUESSED_IP
+	elif [[ "$DEFAULT_PUBLIC_IPV6" == "$GUESSED_IP" ]]; then
+		# No IPv6 entered and machine seems to have none, or what
+		# the user entered matches what the Internet tells us.
+		PUBLIC_IPV6=$GUESSED_IP
+		MATCHED=1
+	elif [[ -z "$DEFAULT_PUBLIC_IPV6" ]]; then
+		DEFAULT_PUBLIC_IP=$(get_default_privateip 6)
 	fi
 
-	echo
-	echo "(Optional) Enter the IPv6 address of this machine. Leave blank"
-	echo "           if the machine does not have an IPv6 address."
+	if [[ -z "$PUBLIC_IPV6" && $MATCHED == 0 ]]; then
+		echo
+		echo "Optional:"
+		echo "Enter the public IPv6 address of this machine, as given to you by your ISP."
+		echo "Leave blank if the machine does not have an IPv6 address."
+		echo
 
-	read -e -i "$DEFAULT_PUBLIC_IPV6" -p "Public IPv6: " PUBLIC_IPV6
+		read -e -i "$DEFAULT_PUBLIC_IPV6" -p "Public IPv6: " PUBLIC_IPV6
+	fi
 fi
 
 # Get the IP addresses of the local network interface(s) that are connected
@@ -182,20 +210,32 @@ fi
 
 # Automatic configuration, e.g. as used in our Vagrant configuration.
 if [ "$PUBLIC_IP" = "auto" ]; then
-	# Use a public API to get our public IP address.
-	PUBLIC_IP=`get_default_publicip`
-	echo "IP Address: $PUBLIC_IP"
+	# Use a public API to get our public IP address, or fall back to local network configuration.
+	PUBLIC_IP=$(get_publicip_from_web_service 4 || get_default_privateip 4)
 fi
 if [ "$PUBLIC_IPV6" = "auto" ]; then
-	# Use a public API to get our public IP address.
-	PUBLIC_IPV6=`get_default_publicipv6`
-	echo "IPv6 Address: $PUBLIC_IPV6"
+	# Use a public API to get our public IPv6 address, or fall back to local network configuration.
+	PUBLIC_IPV6=$(get_publicip_from_web_service 6 || get_default_privateip 6)
 fi
 if [ "$PRIMARY_HOSTNAME" = "auto-easy" ]; then
 	# Generate a probably-unique subdomain under our justtesting.email domain.
-	PRIMARY_HOSTNAME=m`get_default_publicip | sha1sum | cut -c1-5`.justtesting.email
-	echo "Primary Hostname: $PRIMARY_HOSTNAME"
+	PRIMARY_HOSTNAME=`echo $PUBLIC_IP | sha1sum | cut -c1-5`.justtesting.email
+fi
+
+# Show the configuration, since the user may have not entered it manually.
+echo
+echo "Primary Hostname: $PRIMARY_HOSTNAME"
+echo "Public IP Address: $PUBLIC_IP"
+if [ ! -z "$PUBLIC_IPV6" ]; then
+	echo "Public IPv6 Address: $PUBLIC_IPV6"
+fi
+if [ "$PRIVATE_IP" != "$PUBLIC_IP" ]; then
+	echo "Private IP Address: $PRIVATE_IP"
+fi
+if [ "$PRIVATE_IPV6" != "$PUBLIC_IPV6" ]; then
+	echo "Private IPv6 Address: $PRIVATE_IPV6"
 fi
+echo
 
 # Run some network checks to make sure setup on this machine makes sense.
 if [ -z "$SKIP_NETWORK_CHECKS" ]; then