ENG EC 441 Lecture Notes - Lecture 8: Simple Mail Transfer Protocol, Message Transfer Agent, Message Queue

• School: Boston University
• Department: Electrical & Computer Engineering
• Course: ENG EC 441
• Professor: Jeffrey Carruthers

Document Summary

Email apps on computers (outlook, thunderbird, iphone mail client, Allow us ers to read, reply, forward, s ave, and compos e mes s ages. E ach recipient has a mailbox in mail servers. Placed messages in outgoing message queue: mail servers - both sender"s and recipient"s, smtp (simple mail transfer protocol) Uses tcp port 25 - reliable data transfer service. H as 2 s ides : client s ide executes on the s ender"s mail s erver, and s erver s ide to recipient"s mail s erver. Direct transfer - sending server to receiving server, no intermediate server. Application layer hands haking (greeting) - client indicates e- mail addres s of s ender and of recipient. T rans fer of mes s ages - t c p. C los ure - clos e t c p connection. C ommands : 7-bit as c ii text s ent to t c p s ocket.