ike phase 1 lifetime, asa with netscreen

Hi all

Ipsec, L2L, in configuration I set 8h, on both side

IKE Peer: x.y.z.w Type : L2L Role : initiator Rekey : no State : MM_ACTIVE Encrypt : 3des Hash : SHA Auth : preshared Lifetime: 28800 Lifetime Remaining: 24897

but in logs, keys are changing in every 6 hours:

Jun 6 11:17:46 masterasa Jun 06 2009 11:17:46: %ASA-4-713903: Group = x.y.z.w, IP = x.y.z.w Freeing previously allocated memory for authorization-dn-attributes

Jun 6 17:17:46 masterasa Jun 06 2009 17:17:46: %ASA-4-713903: Group = x.y.z.w, IP = x.y.z.w, Freeing previously allocated memory for authorization-dn-attributes

Jun 6 23:17:46 masterasa Jun 06 2009 23:17:46: %ASA-4-713903: Group = x.y.z.w, IP = x.y.z.w , Freeing previously allocated memory for authorization-dn-attributes

Jun 7 05:17:47 masterasa Jun 07 2009 05:17:47: %ASA-4-713903: Group = x.y.z.w, IP = x.y.z.w, Freeing previously allocated memory for authorization-dn-attributes

Someone knows what's reason of that ?

thanks Bart