SmtpMail.SMTPSe rver is a read/write property that you can use to find out what the mail server is. It's fairly common to add a key that represents the SMTP server to web.config or app.config, but one can always set this property dynamically (eg, SmtpMail.SMTPSe rver = mail-relay.foo.com ) It may also help to PING the mail server or connect to port 25 of the mail server to ensure that it's reachable. When all else fails, check with the local admin....