Simple Mail Transfer Protocol, or SMTP, is the server that sends mail with email programs. When you set up an email account, you must define the SMTP address to ensure your email gets to your recipients. You need to know the exact name of this address if you are configuring or troubleshooting an email program.
But in all I have clarify the SMTP.Host like. Smtp.Host = "smtp.gmail.com"; // for example gmail smtp server Write now i am working in the local host only. So what will be the code for that. Thanks in advance. How to Set Up SMTP Using the WP Mail SMTP Plugin Jun 29, 2018 Gmail POP3, IMAP and SMTP settings - HESK.com SMTP Host: smtp.gmail.com SMTP Port: 587 SSL Protocol: OFF TLS Protocol: ON SMTP Username: (your Gmail username) SMTP Password: (your Gmail password) Also make sure your "From email address" in HESK settings is set to your Gmail email address!
Enabling SMTP outbound authentication to relay hosts
SMTP and SMTP/s hosts – Cleo The generic SMTP host provides an interface over non-secure SMTP. If interfacing to a server that requires use of the Secure Socket Layer (SSL) SMTP, then the generic SMTP/s host must be used. Click the Templates tab in the tree pane. If necessary, expand the Hosts tree in the Templates tab to find the host you want to use.
A smart host is a directory server to which SMTP-routed messages are sent when the message recipient cannot be found in the Domino® Directory or other secondary directories configured on the server. Using a Global Domain document to set up a server to receive mail for multiple Internet domains
What is SMTP Host? - Quora Oct 18, 2017