Hi, We're using FreeRADIUS 2.1.6, and have rlm_acct_unique configured as per the below: acct_unique { key = "User-Name, Framed-IP-Address, Acct-Session-Id" } Over the past couple of days we've noticed that the unique session ID calculated by the module during interim updates is changing mid session for some users, although none of the attributes defined in the configuration are changing between requests. Here's an example for a session that had started on 2009-09-06 at 00:31:28: Mon Sep 7 05:00:23 2009 Acct-Session-Id = "01BCBC45" Framed-Protocol = PPP Framed-IP-Address = xxx.xxx.xxx.xxx User-Name = "user@realm" Cisco-AVPair = "connect-progress=LAN Ses Up" Cisco-AVPair = "nas-tx-speed=7349000" Cisco-AVPair = "nas-rx-speed=1000" Acct-Session-Time = 102534 Acct-Input-Octets = 5792373 Acct-Output-Octets = 8666851 Acct-Input-Packets = 79786 Acct-Output-Packets = 54731 Acct-Authentic = RADIUS Acct-Status-Type = Interim-Update NAS-Port-Type = Virtual Cisco-NAS-Port = "Uniq-Sess-ID40" NAS-Port = 40 Service-Type = Framed-User NAS-IP-Address = xxx.xxx.xxx.xxx Acct-Delay-Time = 45 Acct-Unique-Session-Id = "3c17c916d8e9ff20" Timestamp = 1252296023 Request-Authenticator = Verified Mon Sep 7 05:28:24 2009 Acct-Session-Id = "01BCBC45" Framed-Protocol = PPP Framed-IP-Address = xxx.xxx.xxx.xxx User-Name = "user@realm" Cisco-AVPair = "connect-progress=LAN Ses Up" Cisco-AVPair = "nas-tx-speed=7349000" Cisco-AVPair = "nas-rx-speed=1000" Acct-Session-Time = 104260 Acct-Input-Octets = 5895021 Acct-Output-Octets = 8838223 Acct-Input-Packets = 81164 Acct-Output-Packets = 55643 Acct-Authentic = RADIUS Acct-Status-Type = Interim-Update NAS-Port-Type = Virtual Cisco-NAS-Port = "Uniq-Sess-ID40" NAS-Port = 40 Service-Type = Framed-User NAS-IP-Address = xxx.xxx.xxx.xxx Acct-Delay-Time = 0 Acct-Unique-Session-Id = "fb0d91180bc7523e" Timestamp = 1252297704 Request-Authenticator = Verified I've hidden the Framed-IP-Address and User-Name attributes, but they were identical in both requests. Prior to 05:28:2 today, the unique session ID was always returned as 3c17c916d8e9ff20, and since 05:28:24, it has been returned as fb0d91180bc7523e. The only common factor with the sessions where this has happened is the Acct-Delay-Time attribute being set to 45 in the last logged request before the ID had changed, but I can't see any evidence on the server of a delay, or any issues that may have caused a delay, around this time. Does anyone know what might be causing this? Thanks, Tim