Dynamically build your reject_client list based on ip blocks of well known assholes.

Simply add the first three octets of the ip addresses that are giving you guff to the ip_blocks list in block.py

ip_blocks = [
    '185.45.193.',
    '109.206.177.',
    '62.113.250.'
]

Based on your os, your reject_client file might be someplace special. For centos, the path is /etc/postfix/reject_client.

Just set your path as the first argument.

python block.py <path/to/reject_client>

chmod a+x block.py
python block.py /etc/postfix/reject_client