Simple Mail Transfer Protocol (SMTP) uses port _ for communication. 2 years agoby Linux Questions Simple Mail Transfer Protocol (SMTP) uses port _ for communication. › Category: Introduction to Linux II › Simple Mail Transfer Protocol (SMTP) uses port _ for communication. Vote Up 0 Vote Down Linux Questions Staff asked 2 years ago Simple Mail Transfer Protocol (SMTP) uses port ____________ for communication. 23 22 21 25 Please login or Register to submit your answer Username or Email Address Password Remember Me FacebookXGoogle+PinterestLinkedIn