Search in SharePoint Server 2007 and Search Server 2008 can crawl a variety of content sources. For several of the “out of the box” content sources security information in the form of ACLs are collected as part of the indexing process. At query time, search results are trimmed based on the identity of the user submitting the query, and the ACLs collected from crawling.
In certain scenarios, the built-in security trimming is not sufficient for your requirements or the indexing connector isn’t able to collect ACLs at crawl time - in this scenario you'll need to implement a Custom Security Trimmer. For example, content in Novell Netware file shares can be crawled by SharePoint Server 2007 & Search Server 2008(Using the built-in Fileshare Indexing Connector along with Windows Services for Netware) but the indexing connector doesn’t know how to collect ACLs from Netware.
For security trimmed results, that scenario will require a custom security trimmer (CST) to be developed. We recently released a Novell Netware CST on CodePlex as part of the Search Community Toolkit. This can be installed and configured in less than 30 minutes and has been tested against Netware 6.5 although it should work with earlier versions too. It's compatible with SharePoint Server 2007, Search Server 2008, and Search Server 2008 Express.
It includes documentation on how to configure a content source to crawl Netware and how to install the CST. We’ll post the source code for the CST soon once we’ve finished some final testing and the code will be commented and include a doc that provides an overview of the structure of the code and explains where you might want to make your own modifications. This will be great example of how to build your own CST if you’re looking for a good sample to start from.
The initial version was released with an open source license at http://www.codeplex.com/sctcstn and includes the following features: