Keep your E-Mail-Adresse lists up to Datum and remove E-Mail-Adresse addresses which do not exist any longer. You just have to define the path of your E-Mail-Adresse lists. As a result you receive a list with guaranteed valid E-Mail-Adresse addresses, a list containg probably valid E-Mail-Adresse addresses and a list with invalid E-Mail-Adresse addresses. The EmailVerifier uses a proper proofing mechanism, because most of the mail servers have disabled the standard checking command. Further it exposes mail servers, which give the OK return value for every E-Mail-Adresse address.