spoofed email id

[raw]

I can send emails to my exchange5.5 server from outside the domain spoofing a user account email-id which exists inside the domain. after looking at the header it i had the outside ip but its dns name was of my domain's. How can i stop it?

Is there a way to change the SMTP banner on exchange5.5 using microsoft internet mail service?

[gunderstone]

One way I have read about doing this is written up here

http://www.experts-exchange.com/Networking/Email_Groupware/Exchange_Server/Q_20266479.html

I've never done this myself and I don't know if I would risk it in a production environment.

For Exchange 2000 its a little easier

http://support.microsoft.com/default.aspx?scid=kb;en-us;Q281224

XCON: How to Modify the SMTP Banner