[CentOS] Mail from domain problem

> But,  I shutdown Kerio and config MTA = sendmail. 
> Then 
> # service sendmail start 
> # hostname
> mail.domain11.com
> # echo "test " | mail -s "test mail" someone at domain22.com
> 
> 
> I received is root at mail.domain11.com 
> 
> HOW?

With sendmail try to remove root from EXPOSED_USER list.