Distributed processing Electronic data processing Electronic mail systems Συστήματα ηλεκτρονικού ταχυδρομείου Computer Communication Systems Computer networks Computer programs ELECTRONIC MAIL SYSTEMS--COMPUTER PROGRAMS Electronic mail Eletronic mail systems Mail receiving and forwarding services SENDMAIL Security measures Software Αρχές τεχνολογίας λογισμικού ΠΛΗ 11