Customizing sendmail.cf via SuSEconfig
When SuSEconfig runs, the m4 file it uses is treated as a temporary file and is deleted after it is used to create sendmail.cf.
First, be sure that SuSE yast has installed sendmail! Yast wants to install postfix, unless you tell it firmly you want sendmail!
Next get the parameters in /etc/sysconfig/sendmail and /etc/sysconfig/mail as close as possible to the configuration you desire. Use YaST or an editor for this.
/sbin/conf.d/SuSEconfig.sendmail -m4 >myconfig.m4
This will give you a starting point m4 file that depends on the parameters in /etc/sysconfig/sendmail and /etc/sysconfig/mail.
Using your knowledge of sendmail and sendmail m4 features, edit myconfig.m4.
m4 myconfig.m4 >/etc/sendmail.cf
restart sendmail with /etc/init.d/sendmail restart
Make MAIL_CREATE_CONFIG="no" in /etc/sysconfig/mail with YaST or an editor so that YaST does not routinely overwrite your work.