[etc] Allowing roaming users to relay through Sendmail

Following are the steps that I followed to allow roaming users to relay 
through my sendmail server.
I am assuming sendmail is already installed and running on a linux machine.
a. Add the following lines to /etc/mail/sendmail.mc
--SNIP--
FEATURE(`access_db')
FEATURE(`relay_mail_from')
--SNIP--

b. Create the sendmail.cf using the command give at the top of 
/etc/mail/sendmail.mc
make -C /etc/mail

c. Now add the following entries to /etc/mail/access
--SNIP--
From:shashank@cc.cc.edu       RELAY
--SNIP--
d. make the map
%>makemap hash /etc/mail/access.db < /etc/mail/access

e. restart sendmail
%>service sendmail restart

and voila.. if the from field of the message contains shashank@cc.cc.edu 
then the mail gets relayed. This however is not a very good way.. I have 
to look at SMTP AUTH or STARTTLS.Will update this log when i do this.
Shashank