I transitioned from Cistron radius some time ago. There the only option was Exec-Program-Wait. I had developed one that suited our needs. It transitioned quite well to freeradius. However, there are notes in various places that Exec-Program-Wait will somtime go away. The indicated replacement is rlm_exec. I tried to convert my programs over to that and never could quite get everything to work. There were always issues that have been discussed here at length. There were some patches that might have helped my situation, but I didn't want to have to keep remembering to patch new versions etc. Recently I took a more detailed look at rlm_example and decided to give that approach a try. Its actually quite easy to convert an Exec- Program-Wait into a rlm_xxxx. Some of the steps are not obvious and the really difficult part is figuring out what you need to do to get configure to work properly. The real advantage of this, however, is that there is no forking overhead. It runs a lot more efficiently and can do more than what the Exec-Program-Waits can do. Hence, I would suggest that rather than push the rlm_exec as the replacement for Exec-Program-Wait, that creating your own rlm_xxxx would be a better approach. There are no real instructions for creating your own rlm that I could find. However, the experience is still fresh and if you are interested I could put together a first draft of instructions on creating a rlm.