Well you do not mention if this is a Linux or Windows server which is important but assuming your runing under Linux use .htaccess
Code:
order allow,deny
deny from 192.168.44.201
deny from 224.39.163.12
deny from 172.16.7.92
allow from all
OR
Code:
# Deny 69.60.114.0 - 69.60.115.255 (512 addresses)
Deny from 69.60.114.0/23
# Deny 69.60.116.0 - 69.60.119.255 (1024 addresses)
Deny from 69.60.116.0/22
# Deny 69.60.120.0 - 69.60.123.255 (1024 addresses)
Deny From 69.60.120.0/22
# Deny 69.60.124.0 - 69.60.125.255 (512 addresses)
Deny from 69.60.124.0/23
All taken from simple Google searches...