remotesetup.sh

#!/bin/sh
error() { echo "$@" 1>&2; }

domain_files=$1

if [ -z $domain_files ]; then
  error "What is the file with the domains?"
  exit 1
fi

while read domain; do
  echo "Looking for [$(echo $domain)]..."
  mx=$(dig mx +noall +answer +nocomments $domain | head -n 1 | grep -oP 'MX\s[0-9]+\s\K(.+)(?=\.)')
  real_ip=$(ping -c 1 $mx | head -n 1 | grep -oP '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}')

  echo "The real IP from the MX '$(echo $mx)' is '$(echo $real_ip)'"
  echo "\n"
done < $domain_files