By default, SRX 300 Series Firewalls come with predefined security policies:
* Trust-to-Untrust (Option B):A default policy exists to permit all traffic from thetrust zone to the untrust zone.
* Trust-to-Trust (Option D):Intra-zone traffic is permitted by default; hence, a trust-to-trust policy is installed automatically.
* Untrust-to-Trust (Option A):Not allowed by default, since external traffic must be explicitly permitted by an administrator.
* Management-to-Trust (Option C):No such default policy exists.
Correct Policies:Trust-to-Untrust and Trust-to-Trust
Reference:Juniper Networks -Default Security Policies and Intra-zone Rules, Junos OS Security Fundamentals.

To enforce acatch-all blocking policyafter other specific policies, the correct solution is aglobal security policy (Option A).
* Global policiescan apply universally across zones, and an administrator can configure a final "deny all" rule to block any unmatched traffic.
* ATP policy (Option B):Protects against advanced threats, not used for catch-all rule enforcement.
* IDP policy (Option C):Focuses on intrusion detection and prevention signatures, not general traffic blocking.
* Integrated user firewall policy (Option D):Applies policies based on user identity, but it does not provide a universal block across all services.
Correct Solution:Global security policy
Reference:Juniper Networks -Global Security Policies, Junos OS Security Fundamentals.

On SRX Series Firewalls, Junos OS automatically createssystem-defined zonesthat have special functions:
* Null zone (Option A):A predefined discard zone. By default, all interfaces belong to the null zone until assigned to a user-defined zone. Traffic destined to the null zone is dropped.
* Junos-host zone (Option B):A predefined functional zone that allows security policies to control traffic directed to the SRX device itself (management traffic, such as SSH, HTTP, SNMP).
* Management zone (Option C):There is a predefinedmanagement functional zone, but it is not called
"management" as a system-defined security zone.
* DMZ (Option D):A DMZ zone must be explicitly created by the administrator, it is not system-defined.
Correct Zones:null, junos-host
Reference:Juniper Networks -Security Zones and Functional Zones, Junos OS Security Fundamentals.

* License Requirement (Option B):NextGen Web Filtering (NGWF) is a licensed feature on SRX devices. Without a license, the service cannot operate.
* Local vs. Cloud Lists (Option C):NGWF checkslocal block/allow lists first. If the URL does not match locally, the request is then checked against the Juniper cloud database.
* Option A:Incorrect, since the cloud is only consulted if the URL is not in the local list.
* Option D:Incorrect, as NGWF requires a valid subscription/license.
Correct Statements:NGWF requires a license, and it checks local lists before cloud lookup.
Reference:Juniper Networks -UTM Web Filtering Types (NextGen Web Filtering), Junos OS Security Fundamentals.