How does the client communicate with the website?

To communicate with the website, the WhatPulse client uses a SSL encrypted connection. This means it will open a connection to client.whatpulse.org (previous versions used pulse-stats.whatpulse.org) on port 443. If you have a restrictive firewall in place, please allow this connection, or the client will not be able to function properly.

You can use a proxy to relay the clients communication, but it that proxy should not alter the SSL certificate used for communication, as the client will detect that and give an error.