An outgoing SMTP server, also known as an SMTP relay, is responsible for sending email messages from a sender’s email client to the recipient’s email server. It is often provided by an internet service provider (ISP) or a third-party email service provider.
On the other hand, an incoming SMTP server, also known as a POP3 or IMAP server, is responsible for receiving email messages from other email servers and delivering them to the recipient’s email client. It is often provided by the recipient’s email service provider.
In summary, the difference between an outgoing SMTP server and an incoming SMTP server is the direction of the email flow. The outgoing SMTP server sends emails, while the incoming SMTP server receives emails.
