Added notes on use of FreeRADIUS-Acct-Session-Start-Time

diff --git a/raddb/sites-available/default b/raddb/sites-available/default
index 184baa7..f605285 100644 (file)
--- a/raddb/sites-available/default
+++ b/raddb/sites-available/default
@@ -311,6 +311,22 @@ preacct {
        preprocess
 
        #
+       #  Session start times are *implied* in RADIUS.
+       #  The NAS never sends a "start time".  Instead, it sends
+       #  a start packet, *possibly* with an Acct-Delay-Time.
+       #  The server is supposed to conclude that the start time
+       #  was "Acct-Delay-Time" seconds in the past.
+       #
+       #  The code below creates an explicit start time, which can
+       #  then be used in other modules.
+       #
+
+#        update request {
+#              FreeRADIUS-Acct-Session-Start-Time = "%{expr: %l - %{%{Acct-Session-Time}:-0} - %{%{Acct-Delay-Time}:-0}}"
+#      }
+
+
+       #
        #  Ensure that we have a semi-unique identifier for every
        #  request, and many NAS boxes are broken.
        acct_unique