In the context of the Cisco ESA (Email Security Appliance) email pipeline, there are several key phases that emails go through during processing. The 'workqueue' phase involves tasks such as filtering, scanning for threats, and applying policies to the emails. The 'delivery' phase involves sending the processed emails out to their intended recipients while adhering to configured delivery policies. These phases are critical components of the overall email processing pipeline in Cisco ESA.

Cisco ESA (Email Security Appliance) message filters can perform two main types of actions: final actions and non-final actions. Final actions, such as deliver, drop, and bounce, stop any further processing of a message through subsequent filters. On the other hand, non-final actions trigger an action but allow the message to continue being processed by other filters. Therefore, the two correct types of actions performed by Cisco ESA message filters are non-final actions and final actions.

The setting that affects the aggressiveness of spam detection is the spam threshold. This setting determines how strict the spam detection filters are, with lower thresholds resulting in more aggressive spam filtering and higher thresholds allowing more emails to pass through as non-spam.

When multilayer antivirus scanning is configured, the Sophos engine scans for viruses first followed by the McAfee engine. This configuration leverages the strengths of both engines, with Sophos performing the initial scan and McAfee conducting a secondary scan to ensure thorough detection of malware.

The antispam feature that gives end users control over allowing emails to be delivered to their inbox, overriding any spam verdict or action, is the end user safelist. This feature allows users to manage which email addresses they trust, ensuring that messages from these addresses are not marked as spam or quarantined.