How to Find My SMTP Address
Instructions
Using the Command Prompt
1Open the DOS prompt icon in Windows by selecting "Start," and in the provided search box type:
Command Prompt
From the list of programs, click "Command Prompt."
2
Type one of the following commands:
ping smtp.mysite.com
ping mail.mysite.com
3
Locate the name of your SMTP address in the response, which displays immediately after the word "Pinging," and write it down for future reference.
Using Outlook Express
1Open up Outlook Express and click “Tools," "Account Settings" and then the E-Mail tab.
2
Double-click the email account for which you need the SMTP information.
3
View the Server Information, which lists the "Outgoing mail server (SMTP)."
Source...