Acct-Unique-Session-Id Uniqueness

Alan DeKok aland at
Thu Oct 29 12:39:48 CET 2020

On Oct 29, 2020, at 7:29 AM, Ali Arslan via Freeradius-Users <freeradius-users at> wrote:
> I am using freeradius 3.0.20 on ubuntu 20.04 with backend mssql.
> I have problem with the uniqueness of AcctUniqueId ( Acct-Unique-Session-Id ), but they are not unique across radacct table.

  It's as unique as possible.

  If it's not unique, it's likely because the NAS is broken.

> Because there may be multiple records with the same AcctUniqueId value an interim update updates all records with the same AcctUniqueId  value even for different users, which is a problem for usage calculation, and for some other custom calculations, 

  It should be unique for different users.  This is how it works in the default configuration.

> I want to create AcctUniqueId in database as a "uniqueidentifier" so it is unique in database which can be retrieved as a string to be used as "Acct-Unique-Session-Id" in radius when inserting a new record. If it is possible to generate a guid by unlang and use it then it would be better.
> I think raddb/policy.d/accounting file is where this value is created,

  Yes.  Which means you can edit it.

> Any suggestion about making Acct-Unique-Session-Id as unique in radacct table will be greatly appreciated.

  Don't edit the default configuration and break it.

  The Acct-Unique-Session-Id value is calculated by taking an MD5 has of many things, including the User-Name.  If you're seeing the same value for different User-Names, then something has changed from the default configuration.

  Oh, and "something something debug output".  I don't know why I even say that anymore.  It's not like people listen.

  Alan DeKok.

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