GET VPN (Group Encrypted Transport VPN) is a tunnel-less VPN technology that uses a single security association (SA) for all routers in a group. This allows GET VPN to natively support MPLS and private IP networks, without requiring any additional encapsulation or tunneling protocols. GET VPN also supports multicast traffic without GRE, which reduces overhead and improves performance. FlexVPN is a newer VPN solution that covers all VPN types, such as site-to-site, hub and spoke, and remote access. FlexVPN uses IKEv2 for all VPN types, which offers some advantages over IKEv1, such as resiliency and fewer messages.
However, FlexVPN requires newer hardware and software versions to support its features. FlexVPN also relies on GRE or static and dynamic point-to-point interfaces to support MPLS and private IP networks, which adds complexity and overhead. Therefore, a benefit of using GET VPN over FlexVPN within a VPN deployment is that GET VPN natively supports MPLS and private IP networks, without requiring any additional encapsulation or tunneling protocols. References:
* Group Encrypted Transport VPN (GETVPN)
* Introduction to FlexVPN
* what is the difference between dmvpn and flexvpn

Cisco Email Security Appliance (ESA) protects the email infrastructure and employees who use email at work by filtering unsolicited and malicious email before it reaches the user. Cisco ESA easily integrates into existing email infrastructures with a high degree of flexibility. It does this by acting as a Mail Transfer Agent (MTA) within the email-delivery chain. Another name for an MTA is a mail relay.
Reference:
Cisco_SBA_BN_EmailSecurityUsingCiscoESADeploymentGuide-Feb2013.pdf

Cisco Firepower impact flags are indicators that help you evaluate the impact an intrusion has on your network by correlating intrusion data, network discovery data, and vulnerability information1. Impact flags are assigned to intrusion events based on the following criteria:
* The operating system and application protocol of the target host
* The exploitability of the target host by the attacker
* The relevance of the intrusion rule to the target host
* The severity of the intrusion rule Impact flags can have four values: unknown, neutral, affected, or vulnerable. Unknown means that the system does not have enough information to assess the impact.
Neutral means that the system knows the target host is not affected by the intrusion. Affected means that the system knows the target host is affected by the intrusion, but not necessarily exploitable. Vulnerable means that the system knows the target host is exploitable by the intrusion1. Impact flags can help you prioritize your response to intrusion events, as well as generate reports and alerts based on the impact level. You can also use impact flags to filter and search for intrusion events in the Firepower Management Center1. References: 1: Firepower Management Center Configuration Guide, Version 6.1 - External Alerting with Alert Responses.

Cisco Email Security Appliance (ESA) protects the email infrastructure and employees who use email at work by filtering unsolicited and malicious email before it reaches the user. Cisco ESA easily integrates into existing email infrastructures with a high degree of flexibility. It does this by acting as a Mail Transfer Agent (MTA) within the email-delivery chain. Another name for an MTA is a mail relay. Reference: https://www.cisco.com/c/dam/en/us/td/docs/solutions/SBA/February2013/ Cisco_SBA_BN_EmailSecurityUsingCiscoESADeploymentGuide-Feb2013.pdf by filtering unsolicited and malicious email before it reaches the user. Cisco ESA easily integrates into existing email infrastructures with a high degree of flexibility. It does this by acting as a Mail Transfer Agent (MTA) within the email-delivery chain. Another name for an MTA is a mail relay.
Reference:
Cisco Email Security Appliance (ESA) protects the email infrastructure and employees who use email at work by filtering unsolicited and malicious email before it reaches the user. Cisco ESA easily integrates into existing email infrastructures with a high degree of flexibility. It does this by acting as a Mail Transfer Agent (MTA) within the email-delivery chain. Another name for an MTA is a mail relay. Reference: https://www.cisco.com/c/dam/en/us/td/docs/solutions/SBA/February2013/ Cisco_SBA_BN_EmailSecurityUsingCiscoESADeploymentGuide-Feb2013.pdf