django-helpdesk includes a copy of akismet.py by Michael Foord, which lets incoming ticket submissions be automatically checked against either the Akismet or TypePad Anti-Spam services.
To enable this functionality, sign up for an API key with one of these two services.
Note: Akismet is only free for personal use. Paid commercial accounts are available.
This service is free to use, within their terms and conditions.
If you have either of these settings enabled, the spam filtering will be done automatically. If you have both settings configured, TypePad will be used instead of Akismet.