ext-Dns license model is based on providing the source code under a set of terms that allows to develop commercial and proprietary applications.
ext-Dns code, its base library and some modules are released under the LGPL 2.1 library. This allows to use and link against ext-Dns using Open Source as well as Commercial applications, provided some conditions. Read full license description at: LGPL 2.1.
ASPL is releasing ext-Dns with no royalty or fee, even for commercial development. However, using ext-Dns in any form doesn't implies to receive guaranteed support and any other professional services. If your intention is to receive professional guaranteed support please read: professional services
With the intention to provide a brief, though not comprehensive list, here is the set of general conditions:
You can develop Open Source and Commercial applications that uses ext-Dns in any way.
All modifications done to the ext-Dns code must be returned back either to the ext-Dns repository or included with your application. You can't make private changes to ext-Dns without making them available to your customers or end users. In the case you want to do so, you must buy a ext-Dns Commercial License.
You can modify, copy, redistribute and use ext-Dns and its associated code with no restriction but without ANY WARRANTY, OF ANY KIND. If you want some levels of warranty you must buy a ext-Dns Support contract.
You can contact us for licensing and support questions at: <firstname.lastname@example.org> (English or Spanish).