Hi I need to set some of our boxes to send mail through our smarthost. In the sendmail.mc file i have set the smarthost and rebuilt the sendmail.cf file. When i send a mail locally on the box though i get this error Diagnostic-Code: SMTP; 553 5.1.8 <root at localhost.localdomain>... Domain of sender address root at localhost.localdomain does not exist What else do i need to edit as there is something that talks about sending from unresolvable domains but this is already allowed i think FEATURE(`accept_unresolvable_domains')dnl any ideas ? thanks