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rlm_acct_unique - FreeRADIUS Module

rlm_acct_unique(5) FreeRADIUS Module rlm_acct_unique(5)


rlm_acct_unique - FreeRADIUS Module


The rlm_acct_unique module creates a unique accounting session Id.
Many NAS vendors have their equipment supply an Acct-Session-Id attribute which is not unique over reboots. This makes accounting difficult, as there will be many independent sessions with the same Acct-Session-Id attribute. This module uses the Acct-Session-Id attribute, along with other attributes in the request, to create a more unique session ID, called Acct-Unique-Session-Id.
The main configuration items to be aware of are:
A list of the attributes used in calculating an MD5 hash which is used as the value for the unique session id.


modules { ...
acct_unique {
key = "User-Name, Acct-Session-Id, NAS-IP-Address, NAS-Port"
preacct { ...
acct_unique ...
After generating the MD5 hash, the module adds it to the accounting request packet received from the client. It will look something like this in your detail file:
Acct-Unique-Session-Id = "c66ef57e480b9d26"
NOTE: Any attribute you specify that is not found in the 'dictionary' file will cause the server to fail and exit with an error.
NOTE: If you want the Acct-Unique-Session-Id of the Start and the Stop packet of a particular session to match, you must use values for the key that will stay the same for the Start and Stop. The above example is a good start. Adding 'Acct-Session-Time', for example, would cause a mismatch because that value is not the same on the Start and Stop accounting packets.


authorization, pre-accounting, accounting




radiusd(8), radiusd.conf(5)


Chris Parker,
3 February 2004