By default, Junos denies all traffic through an SRX Series device. Actually an implicit default security policy exists that denies all packets.
Default policy: deny-all
You can modify this behavior to permit-all (not suggested) doing:
[edit security policies]
The other reference "Pre ID default policy:permit-all" is related to the APPid process. If you don't have the license for download the Appid database, don't consider it yet for now. https://www.juniper.net/documentation/us/en/software/junos/appaware-services/topics/concept/appid-overview.html.Before an application is identified by Application Identification (AppID), the pre-ID-default-policy options are applied to the session.