The problem with creating a VPN tunnel is that it's hard to recreate the IP address of the machine on which you're installing the software. To solve this, I created a script that automatically creates and connects a VPN tunnel to my VM.
#!/bin/bash
function ask_yes_or_no() {
read -p "$1 ([y]es or [N]o): "
case $(echo $REPLY | tr '[A-Z]' '[a-z]') in
y|yes) echo "yes" ;;
*) echo "no" ;;
esac
}
currNatRules=$(sudo pfctl -a com.apple.internet-sharing/shared_v4 -s nat 2>/dev/null)
if test -z "$currNatRules"
then
echo -e "\nThere are currently no NAT rules loaded\n"
exit 0
fi
utunCheck=$(echo $currNatRules | grep utun)
if test -n "$utunCheck"
then
echo -e "\nIt looks like the VPN tunnel utun2 has already been created"
echo -e "\n$currNatRules\n"
if [[ "no" == $(ask_yes_or_no "Do you want to continue?") ]]
then
echo -e "\nExiting\n"
exit 0
fi
fi
natCIDR=$(echo $currNatRules | grep en | grep nat | cut -d\ -f 6)
if test -z "$natCIDR"
then
echo -e "\nCannot extract the NAT CIDR from:"
echo -e "\n$currNatRules\n"
exit 0
fi
interface=$(route get 10/8 | grep interface | cut -d\ -f 4)
echo -e "\nNAT CIDR=$natCIDR Interface=$interface\n"
newRule="nat on ${interface} inet from ${natCIDR} to any -> (${interface}) extfilter ei"
echo -e "\nAdding new rule: $newRule\n"
configFile="fixnat_rules.conf"
[[ -d $configFile ]] && rm $configFile
echo "$currNatRules" > $configFile
echo "$newRule" >> $configFile
sudo pfctl -a com.apple.internet-sharing/shared_v4 -N -f ${configFile} 2>/dev/null
echo -e "\nConfig update applied\n"
sudo pfctl -a com.apple.internet-sharing/shared_v4 -s nat 2>/dev/null
echo -e "\n"
exit 0