[Exim] Sending FRom command prompt yields error

When I try to mail to an external email account using mail I receive the
following error in the log file. It seems that it is using my linux machine
name instead of a FQDN. Is there a simple configuration change that I can
make to get this too work? Thanks


myyahooaddress@??? R=dnslookup T=remote_smtp: SMTP error from remote
mailer after MAIL FROM:<root@prupref-mail> SIZE=1333: host
mx1.mail.yahoo.com [64.156.215.6]: 501 Syntax error in parameters or
arguments
2003-10-16 11:22:25 1AAAtN-0005XC-Vx <= <> R=1AAAtM-0005X9-U5 U=exim P=local
S=1208
2003-10-16 11:22:26 1AAAtM-0005X9-U5 Completed
2003-10-16 11:22:26 1AAAtN-0005XC-Vx ** root@prupref-mail: Unrouteable
address
2003-10-16 11:22:26 1AAAtN-0005XC-Vx Frozen (delivery error message)