Many thanks to:
Sheila Hollenbaugh, Mike caplin, Peter Stern
Answer ===================================================
The trusted users are set in the sendmail.cf file, one way follows:
#####################
# Trusted users #
#####################
# this is equivalent to setting class "t"
Ft/etc/mail/trusted-users
Troot
Tdaemon
Tlistmgr
Received on Mon Dec 16 2002 - 16:02:41 NZDT