What are some of the comparison between SMTP and HTTP? Both are used to transfer files
from one host to another. HTTP transfer files from a Web server to a Web client; SMTP transfers files from one mail server to another mail server. When transferring files, both persistent HTTP and SMTP use persistent connections, thus the two protocols have
common characteristics. What about some of the differences? HTTP is mainly a pull protocol—someone loads information on a Web server and users use HTTP to pull the information from the server at their convenience. The TCP connection is imitated by the machine that wants to receive the file. SMTP is primarily a push protocol—the sending mail
server pushes the file to the receiving mail server. The TCP connection is initiated by the machine that wants to send the file. Another difference is that SMTP requires each message,
including the body of each message be in a 7-bit ASCII format. If the message contains characters that are not in this format, then the message has to be encoded into 7-bit ASCII.
HTTP data does not impose this restriction. A final difference concerns how a document
consisting of text and images is handled. HTTP encapsulated each object in its own HTTP
response message. Internet mail places all of the message's objects into one message.