Microsoft provides a powerful API to interact with web content passing through the ISA/TMG proxy, allowing dramatic expansion and control over its feature set. But there are many limitations:
- In the ISA/TMG interface, there is no facility to add or modify HTTP headers, just to block them.
- In the ISA/TMG interface, there is no facility to modify request or response bodies, just a limited ability to block by simple signatures.
- Filters must be coded as C/C++ DLLs.
- A high level of expertise is needed to avoid memory leaks or crashing the firewall service!
- It is very work-intensive to build a proof of concept filter.
- Due to the need for expert development, producing even small filters may be prohibitively expensive for many organizations.
Solution
IsaScript from Collective Software is a filter for ISA 2006/2004 and TMG that wraps the web filtering API and exposes it via the popular and easy to learn Lua scripting language. Create filters the fast and easy way.
- Majority of the web filter API is exposed to Lua script.
- Improved content matching abilities not available in the native ISA/TMG API.
- No knowledge of C/C++ needed.
- Lua errors are handled and reported gracefully; no need to worry about memory leaks or firewall crashing.
- Useful for rapid filter prototyping, or even on production systems. Lua scripting incurs only a minimal performance overhead.
- Veteran ISA filter developers will find IsaScript intuitive to use, because it mirrors the C/C++ API in many ways.
- Build your own filters, or take advantage of our expert consultants to help create the perfect solution.
- IsaScript filter development work is far less expensive than building a native C/C++ filter.
We continue to refine and add features to IsaScript to make it a more complete solution. We invite your feedback and feature suggestions.
The current release of IsaScript is version 0.3.5
Download IsaScript documentation
Download IsaScript for ISA (evaluations must be activated in 30 days)
Download IsaScript for TMG (evaluations must be activated in 30 days)
Purchase IsaScript licenses online
IsaScript knowledge base articles