Running external programs

[rihad]

Hi, all. We have some legacy software that ran under XTradius 
(xtradius.sourceforge.net). The important thing was to execute an 
external program for every auth & accounting request. Now I need to 
recreate all that on another server, and I must use the same legacy 
billing software. Unfortunately one can no longer build the old XTradius 
on modern FreeBSDs, apparently it has some variable linkage problems. 
Can that simple task be done in FreeRADIUS instead? Can it be configured 
to call an external program (Auth-Type "External" in XTradius)?

Thanks!