Explanation
Encrypted Traffic Insights is a feature of Juniper ATP Cloud and SRX Series firewalls that can detect malicious threats that are hidden in encrypted traffic without intercepting and decrypting the traffic. It permits organizations greater visibility and policy control over encrypted traffic, without requiring resource-intensive SSL Decryption1.
Encrypted Traffic Insights assesses the threat of the traffic by using two methods:
It validates the certificates used by the external servers that the internal hosts are trying to connect to. It compares the certificate signatures with a blocklist of known malicious certificates and also checks the certificate validity, issuer, and subject. If the certificate is invalid or matches a malicious signature, the connection is blocked or alerted2.
It reviews the timing and frequency of the connections to the external servers. It uses behavior analysis and machine learning to identify patterns and anomalies that indicate malicious activity, such as command and control (C&C) communications, botnet traffic, or data exfiltration. It also uses threat intelligence feeds to enrich the analysis and provide additional context2.
Encrypted Traffic Insights does not decrypt the file or the data in a sandbox or to validate the hash, as these methods would require breaking the encryption of the traffic, which would violate data privacy laws and introduce latency and performance issues21. References:
3: SRX5400, SRX5600, SRX5800 Firewalls Datasheet - Juniper Networks
2: Encrypted Traffic Insights Overview and Benefits | ATP Cloud | Juniper ...
1: Juniper Networks Expands Connected Security Portfolio with Encrypted ...

Juniper ATP Cloud is a cloud-based service that provides advanced threat prevention and detection for your network. It integrates with SRX Series firewalls and MX Series routers to analyze files and network traffic for signs of malicious activity. Juniper ATP Cloud protects a network from zero-day threats by using dynamic analysis, which is a method of executing files in a sandbox environment and observing their behavior and network interactions. Dynamic analysis can uncover unknown malware that may evade static analysis or signature-based detection methods.

Explanation
An Application Layer Gateway (ALG) is a software component that is designed to manage specific protocols such as Session Initiation Protocol (SIP) or FTP on Juniper Networks devices running Junos OS. The ALG module is responsible for Application-Layer aware packet processing on switches1. The ALG can perform various functions such as modifying the payload and header of packets, opening secondary connections, translating addresses and ports, and applying security policies1. The ALG does not use software processes for permitting or disallowing specific IP address ranges, as this is the function of firewall filters or security zones2. The ALG does not use software that is used by a single TCP session using the same port numbers as the application, as this is the definition of a stateful firewall3. The ALG does not contain protocols that use one application session for each TCP session, as this is the characteristic of some application protocols such as HTTP or SMTP4. References:
1: ALG Overview | Junos OS | Juniper Networks
2: Firewall Filters Overview | Junos OS | Juniper Networks
3: Stateful Firewall Overview | Junos OS | Juniper Networks
4: Application Layer Protocols | Junos OS | Juniper Networks