Access-Request Identifier field

Peter Molnar at
Sat Dec 12 04:34:55 CET 2009


First of all, sorry for posting to the devel list, but my question is
quite technical, I think this list suits better than

I'm developing a limited, minimalistic "implementation" of a RADIUS
client for an embedded system. (Basically it's just sending an
Access-Request, receiving a reply, and acting upon it)

I have a question about the Identifier field of the Access-Request
packet. According to RFC 2865:

"The Identifier field MUST be changed whenever the content of the
Attributes field changes, and whenever a valid reply has been received
for a previous request.  For  retransmissions, the Identifier MUST
remain unchanged."

OK, that means I have to generate a random octet for this field, that
is different from the Identifier of the previous request. But, do I
have to preserve the value of the last Identifier between client
reboots? What happens, if the server receives a packet, with the same
Identifier, as the previous, but with different authentication data
(the random number generator gives the same value as the previous
Identifier)? It gets treated as a retransmission, without actually
processing the new data?

Does the official freeradius client preserve the previous Identifier
value between server restarts?

I'm using freeradius version 2.0.4.


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