LOCAL_RULESETS HSubject: $>Check_Subject
D{MPat}ILOVEYOU
D{MMsg}This message may contain the LoveLetter virus. SCheck_Subject
R${MPat} $*$#error $: 550 ${MMsg}
RRe: ${MPat} $*$#error $: 550 ${MMsg}
In this case, we are blocking the ILOVEYOU virus.
“D{MPat}ILOVEYOU” is what’s in the subject line when the message comes in.“D{MMsg}This message may contain the LoveLetter virus.” is the message that sendmail will give to the sender. You are free to be creative with this message and you could also create a universal error message for all of the mails with the subject line you want to block.
If you have a huge list of subject lines you want to block, you could do it this way:
LOCAL_RULESETS HSubject: $>Check_Subject
D{MPat}ILOVEYOU
D{MPat2}Mother’s Day Order Confirmation
D{MPat3}Important ! Read carefully !!
D{MMsg}Your mail has been rejected because it may have a virus. SCheck_Subject
R${MPat} $*$#error $: 550 ${MMsg}
RRe: ${MPat} $*$#error $: 550 ${MMsg}
R${MPat2} $*$#error $: 550 ${MMsg}
RRe: ${MPat2} $*$#error $: 550 ${MMsg}
R${MPat3} $*$#error $: 550 ${MMsg}
RRe: ${MPat3} $*$#error $: 550 ${MMsg}
Hopefully, you get the idea here. After all this, you have to recompile the sendmail.cf file and restart sendmail for this to take effect. To recompile the sendmail.cf file:
1 – backup your original /etc/mail/sendmail.cf
2 – in the /usr/lib/mail/cf directory, run:
/usr/ccs/bin/m4 ../m4/cf.m4 main.v7sun.mc > /etc/mail/sendmail.cf To restart sendmail:
/etc/init.d/sendmail stop
/etc/init.d/sendmail start Have fun!]]>