IP

IP blacklisting is a common operation in public services. This feature should only be used as the 'last resort' when you have not more resources to deal with the undesired site access. Blocking by IP address may unintentionally block many users.

Modules for Drupal 7

GoAway

simple light-weight "Ban By IP" module. Designed especially for high-traffic sites which can't (or don't want to) bear the combined load of the Statistics and Tracker modules. The entire purpose of GoAway is to make IP banning as easy as editing a comment.

IP Ranges

Blacklist or whitelist.

Domain IP

Blacklist and whitelist. Works with “Domain access”.