SMTP is a system used to route email through the internet. The email reaches the SMTP server and gets rerouted to the recipient. Usually the SMTP server is set for a particular internet service provider and does not work when the person is travelling. A global SMTP server is required for the email to work in locations all over the globe. SMTP and POP3 settings are essential for sending and receiving emails. When the default SMTP server does not work while travelling, a server with global access has to be used to send and receive emails. Global smtp servers allow the person to check emails on a laptop or phone anywhere in the world without having to change the email settings. The SMTP server understands simple text commands such as HELO, MAIL FROM, DATA, QUIT, HELP, EXPN, VERB, VRFY etc. Some service providers have global access and do not need to be changed.