SendMail Configuration
Overview
Configuring sendmail MTA has a huge literature, only small tips will be described here.
The basis is the simple default configuration file on CentOS. See /etc/mail/sendmail.mc.orig. The goal of the changes to relay all outgoing emails from my CentOS workstations to my ISP and masquerade the domain and even the real linux user name to my email address at the ISP. See the complete configuration file /etc/mail/sendmail.mc.