how to prevent mail from abc.com?

[yiutin03]

how to configure the sendmal so that mail from abc.com is blocked?

 

[trabadam]

When I installed sendmail 8.12.8, I did the following (among other things)
added strings

FEATURE (`access_db')
dnl this sets DNS-based ACL
FEATURE (`relay_hosts_only')
dnl treating records in ACL as the names of hosts, not domains

to the file <sendmail_pkg>/cf/cf/sendmail.mc and built it
cd <sendmail_pkg>/cf/cf/sendmail.mc
./Build sendmail.cf
./Build submit.cf

After the binaries and *cf were installed, I created /etc/mail/access with records like

localhost RELAY
localhost.localdomain RELAY
# consult your /etc/hosts for exact FQDN of your localhost
127.0.0.1 RELAY
my_left_hand_side_neighbour.myoffice.my.net RELAY
my_right_hand_side_neighbour.myoffice.my.net RELAY
# any hosts not listed here are denyed by default

and compiled it with
cd /etc/mail
makemap hash access.db < access

Note, that this may be circumvented by dedicated software that can answer forged hostnames!!!

 

[TalentedFool]

All you need to do is to add the line

abc.com reject

to the access file and recompile the access db file (makemap hash /etc/mail/access.db < access)

Stop and restart sendmail and this should prevent mail from abc.com entering your system.

~ Remember - Nothing is Fool Proof to a Talented Fool ~