Block Sending From Specific IP Addresses

PROBLEM

I need to block sending from my server from specific IP addresses.

ENVIRONMENT

• On-Premise Server + WebMail Installations: Version 6.0 > Current Version

CAUSE

Anti-Spam requirement.

RESOLUTION

1. Open and edit /usr/local/atmail/mailserver/configure.
   
   
2. Locate:
   

   domainlist dkim_off =

3. Add:
   

   hostlist bad_ips = /usr/local/atmail/mailserver/bad_ips

   Example:
   

   hostlist bad_ips = /usr/local/atmail/mailserver/bad_ips
   domainlist dkim_off =

4. Locate:
   

   acl_smtp_rcpt = acl_check_rcpt

5. Add:
   

   acl_smtp_connect = acl_check_connect

   Example:
   

   acl_smtp_connect = acl_check_connect
   acl_smtp_rcpt = acl_check_rcpt

6. Locate:
   

   begin acl

7. Add:
   

   acl_check_connect :
   
   drop
                   hosts = : +bad_ips
                   message = Rejected - IP [$sender_host_address:ip] is listed in bad IPs
                   logwrite = LOG:ACL_CONNECT:REJECT:$sender_host_address:ip $sender_host_address is listed in Bad IPs
   
   accept

   Example:
   

   begin acl
   
   acl_check_connect :
   
   drop
                   hosts = : +bad_ips
                   message = Rejected - IP [$sender_host_address:ip] is listed in bad IPs
                   logwrite = LOG:ACL_CONNECT:REJECT:$sender_host_address:ip $sender_host_address is listed in Bad IPs
   
   accept

8. Save changes and exit.
   
   
9. Create /usr/local/atmail/mailserver/bad_ips.
   
   List IP addresses you wish to block. New line for each IP.
   
   Example:
   

   11.11.11.11
   22.22.22.22
   33.33.33.33

10. Restart atmail services for the changes to take affect.
    /etc/init.d/atmailserver restart