# Prompt the user to enter custom upstream servers
piholeDNS=$(whiptail --backtitle "Specify Upstream DNS Provider(s)" --inputbox "Enter your desired upstream DNS provider(s), separated by a comma.\\n\\nFor example '8.8.8.8, 8.8.4.4'" "${r}""${c}""${prePopulate}" 3>&1 1>&2 2>&3)||\
piholeDNS=$(whiptail --backtitle "Specify Upstream DNS Provider(s)" --inputbox "Enter your desired upstream DNS provider(s), separated by a comma.\\n\\nFor example '8.8.8.8, 8.8.4.4' or '127.0.0.1#5335'" "${r}""${c}""${prePopulate}" 3>&1 1>&2 2>&3)||\
{printf" %bCancel was selected, exiting installer%b\\n""${COL_LIGHT_RED}""${COL_NC}";exit 1;}
# Clean user input and replace whitespace with comma.