How to "fix" system's sendmail to use that of zimbra

How to "fix" system's sendmail (/usr/sbin/sendmail) for zimbra

(supposing system has alternatives, like debian, centos, ...)

First check what's there now:

     [root@zimbra ~]# ls -l /usr/sbin/sendmail
     lrwxrwxrwx 1 root root 21 Jun 23 12:21 /usr/sbin/sendmail -> /etc/alternatives/mta

     [root@zimbra ~]# update-alternatives --display mta
     mta - status is auto.                             
      link currently points to /usr/sbin/sendmail.sendmail
     /usr/sbin/sendmail.sendmail - priority 90            
      slave mta-mailq: /usr/bin/mailq.sendmail            
      slave mta-newaliases: /usr/bin/newaliases.sendmail  
      slave mta-rmail: /usr/bin/rmail.sendmail            
      slave mta-sendmail: /usr/lib/sendmail.sendmail      
      slave mta-pam: /etc/pam.d/smtp.sendmail             
      slave mta-sendmailman: /usr/share/man/man8/sendmail.sendmail.8.gz
      slave mta-mailqman: /usr/share/man/man1/mailq.sendmail.1.gz      
      slave mta-newaliasesman: /usr/share/man/man1/newaliases.sendmail.1.gz
      slave mta-aliasesman: /usr/share/man/man5/aliases.sendmail.5.gz      
     Current `best' version is /usr/sbin/sendmail.sendmail.                

Then install alternative and check it:

     [root@zimbra ~]# update-alternatives --install /usr/sbin/sendmail mta-sendmail /opt/zimbra/postfix/sbin/sendmail 25
     [root@zimbra ~]# update-alternatives --display mta-sendmail
     mta-sendmail - status is auto.
      link currently points to /opt/zimbra/postfix/sbin/sendmail
     /opt/zimbra/postfix/sbin/sendmail - priority 25
     Current `best' version is /opt/zimbra/postfix/sbin/sendmail.