Question : Can I basically turn SMTP relay off?

I've been doing some research about SMTP relay (this is for the most part all new to me) and wonder.

If all the email addresses that my company uses are in house (ie.www.domainname.com), can I effectively tell Exchange to only relay addresses from that domain thereby reducing or potentially eliminating any SMTP relay other than my own?

Answer : Can I basically turn SMTP relay off?

Use the link posted by "gupnit:". i will provide u detail info about check SMTP relay.

If you disable SMTP relay it will not affect your inbound, or outbound emails. it will only stops relaying from outside servers and as a standard security practice you should disable SMTP relay unless you have external servers configured to use your sever for relaying.