If you are trying to use an email client such as Outlook or Apple Mail, you must know your email's SMTP server address in order to sent outgoing mail. Your SMTP server address is dependent on your Internet service provider (ISP), so if you want to know your SMTP server address, you must first know what company supplies your Internet. Once you know your ISP, you can determine your SMTP by matching your ISP's name with one of the many ISP SMTP databases that can be found on the Internet.
Determine who your Internet service provider is. Your Internet service provider is the company that supplies you with an Internet connection. If you do not know the name of your Internet service provider, look at one of your monthly Internet bills.
Open a Web browser and navigate to a website that catalogues the SMTP server addresses for the different Internet service providers. Host45.com, amailsender.com and smtpserverlist.com are a few of the websites that contain such a database.
Locate your Internet service provider in the list of ISPs. Listed next to your ISP will be your ISP's SMTP server address.