Windows System Software -- Consulting, Training, Development -- Unique Expertise, Guaranteed Results


Before Posting...

Please check out the Community Guidelines in the Announcements and Administration Category.

More Info on Driver Writing and Debugging

The free OSR Learning Library has more than 50 articles on a wide variety of topics about writing and debugging device drivers and Minifilters. From introductory level to advanced. All the articles have been recently reviewed and updated, and are written using the clear and definitive style you've come to expect from OSR over the years.

Check out The OSR Learning Library at:


liangdodoliangdodo Member Posts: 9

Hello everyone!
I have a question about WFP, registered FWPM_LAYER_ALE_AUTH_CONNECT_V4 to filter outbound authorization callback function classifyFn(), my understanding is that the TCP data of the application layer will call back my registered classifyFn() when calling connect(), but for UDP I have 2 questions that I don't quite understand, as follows:
1. For UDP data, does the application layer call my registered classifyFn() when calling sendto() for the first time?
2. When will the UDP of the application layer be re-authorized? I found that after the first authorization of UDP, if no data packets are sent for a period of time, it will be re-authorized?

Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. Sign in or register to get started.

Upcoming OSR Seminars
OSR has suspended in-person seminars due to the Covid-19 outbreak. But, don't miss your training! Attend via the internet instead!
Writing WDF Drivers 12 September 2022 Live, Online
Internals & Software Drivers 23 October 2022 Live, Online
Kernel Debugging 14 November 2022 Live, Online
Developing Minifilters 5 December 2022 Live, Online