I tried to set in sendmail.mc file at the LAST line define(`LUSER_RELAY', `local:unknownuser') dnl I did service sendmail restart and got an error on a completely different line. - as a thought I deleted that line and put it on line 2 of the sendmail.mc file. re-ran service sendmail restart and now it worked. I changed nothing else. Is there something special about the placement of this command??? Thanks, Jerry