I'm not sure if this is the right place for this particular subject, but couldn't find an 'E-mail Security' forum, so here goes
If you're able to telnet into an SMTP server on port 25, but not able to run expn or vrfy (M$ Exchange server does not have these features to begin with) or send messages (server not configured to relay) is there anything to worry about?
I'm asking because I recently installed Exchange 2000. I just read an article on finding information out about a particular user when you've got their e-mail address. The article went over the commands above and and a couple of other items. I'm able to telnet into my mail server from the outside, but didn't know if being able to do this alone presented some sort of situation. Is it necessary (or even possible for that matter) to block telnet on port 25? If so, how can this be configured on Exchange 2000?