Centos 5 Hello I successfully converted my mta from sendmail to postfix. no problem. mail is ok. A by-product of that, as bizarre as it may seem is this: As regular user, when I do 'su -' to become root, all is well. As regular user, when I do 'sudo bash' I become root alright but I also get: sendmail: fatal: Recipient addresses must be specified on the command line or via the -t option I tried many things ranging from temporarily swapping sendmail.postfix to messing around with /etc/profile and /etc/skel/* and many other things. How can I address the annoying message above? Thanks, Farid