hello mr. administrator good evening (indonesian time : 7:20 PM)

i want to asking about sendmail through my network
recently i installed a server for my co-workers

i installed sendmail pack (include devel and cf version)
also imap-2001 ( i am using RedHat 7.3 / for IMAP and POP3)
and webmin default port that's fine i think ? i asked my friend that he could handle the sendmail configuration via webmin ! but he forgot what kind file it is (on M4 configuration) he said you just delete some configuration that can make some domain and IP address to access! can you tell me whereis the line it's only

dnl Uncomment this following line ....................