Thank you so much!
I will check the show security flow session summary command.
>Are the failed sessions continuosly increasing on the SRX ?
Yes, they have been increasing since we started using it.
By the way I think I have to change security policy to get needed information. Do you think that SRX650's performance would be effected by changing it?
set security policies from-zone trust to-zone untrust policy default-permit then log session-init
set security policies from-zone trust to-zone untrust policy default-permit then log session-close