/
(?:\s*from\s(?:(?:([^\(]*?)\s)|(\[[^\]]*\]))(?:\((?:(?:((?!HELO|EHLO)[^\s]*)|(?:(?:EHLO)|(?:HELO)))?(?:[\s\w\.]*(?:(?:\[([^\]]*)\])|([^\)\s]*))\))))?(?:\{.*\})?)?
\s*(?:[\(\{\[]+([^\)\}\]]*)[\)\}\]]+\;?)?
(?:[\s\n]*)
(?:\s*by(?!.*with).*\;?)?
(?:\s*by\s(.*(?=with)\)?)\s*)?
(?:with\s*(?:((?:[^\n;]*))(?:.*\;)?))?
(?:[\s\n]*)?
(?:for\s[^\;]*\;)?
(?:envelope-from\s*([^\n]*)\;?)?
(?:[\s\n]*)?
(?:\(.*\)\;)?(?:[\s\n])?
(.+)?
/
mx