Does the .SNF file keep growing in size?
No, but the rulebase file size will change frequently, usually not by very much. The scanning engine is very efficient – so much so that the size of the rulebase could change significantly without any measurable effect on scanning performance. That said, we do monitor things constantly to make sure everyone has the best performance we can provide. The rules that are in the live rulebase are constantly changing based on activity. All of the rules compete to remain in the active rulebase and those that are less efficient or are no-longer useful are made inactive. This constant competition keeps the rulebase as efficient as possible and prevents it from growing without bounds.