This module enables anonymous users to vote on polls without page cache troubles or IP address restrictions. It is designed to work on top of core Poll module.

Current features:

• Page caching can be enabled even if the anonymous users are allowed to vote on polls.
• IP address restriction has been changed to cookie based solution so that users behind a firewall will be able to vote
• To prevent abuses, IP addresses are checked against the most latest votings. The threshold value can be changed from module's settings page.

Note: This module is in active development, and thus not ready for production usage.

You may also want to consider testing the Poll Improved module with D7. It is a successor of this module using entities and fields thus providing more flexibility with minimal complexity.