Configuring a Sender Group within the Inbound Mail Policies allows for granular control. Setting the Spam Action to ‘Skip’ for this specific sender group bypasses spam filtering (including graylisting, reputation, and message filters), while the global Anti-Virus policy, which operates independently, will still scan the messages for malware. This is the most direct and policy-driven method to meet the exact requirement.

The `mail_logs` file (e.g., `mail_logs.current`) is the comprehensive transaction log for the ESA. It records a sequential entry for every processing step applied to each message, including connection, reception, policy and filter matches (anti-spam, anti-virus, content filters, DLP), and final disposition (delivered, quarantined, bounced). Using the message ID to grep this log provides the complete forensic trail.

Modern web applications heavily rely on encrypted WebSocket (WSS) connections for real-time data. If a Decryption policy does not explicitly include the domain `app.trustedvendor.com` (or its parent), the WSA cannot inspect the encrypted WebSocket traffic. By default, the proxy may block or mishandle encrypted connections it cannot decrypt, leading to application failure. Creating a Decryption policy to decrypt traffic for this trusted site is often the crucial step.

To control where data can go, you must first identify the destination. The WSA’s URL categorization database includes a ‘Cloud Storage’ category. An Access Policy uses this category as a **destination** condition. Within that Access Policy, you can then enable a DLP scan (e.g., using the PCI template) and set the action to ‘Block’ with a user notification. The DLP engine detects the content, but the Access Policy framework defines where the rule applies.

Outbreak Filters provide cloud-based, real-time threat intelligence. When the ESA encounters an unknown file or URL, it queries the Cisco Talos Threat Intelligence cloud with identifiers like file hashes. Talos analyzes the artifact using its global sensors and research, returning a near-instantaneous reputation score (malicious, clean, or unknown). This allows the ESA to block true zero-day threats before traditional signature updates are available.

In explicit proxy mode, the ‘Require authentication for all requests’ setting dictates when the proxy challenges the user. If this is disabled (the default in some templates), the WSA will only demand credentials when a user’s request matches a policy that *specifically requires authentication*. For example, a policy for ‘Social Media’ may have ‘Identify’ as an action, triggering a login prompt only when accessing Facebook. Enabling this setting forces authentication at the very first web request, providing immediate user identification.

ESA has configurable rate limits for outbound messages per sender (e.g., messages per hour). A sudden spike triggering this limit for a single user account is a classic indicator of account compromise. A malicious actor has obtained the credentials and is using the compromised account to send spam or phishing emails from within the organization. The immediate focus should be to isolate the account (disable it), reset credentials, and scan the user’s endpoint for malware, not to adjust ESA rate limits.

To decrypt HTTPS traffic, the WSA performs a Man-in-the-Middle (MiTM) operation. It terminates the client’s TLS connection using a certificate it generates on-the-fly for the requested website. For the client’s browser to trust this forged certificate, the WSA’s internal CA certificate (which signed it) must be installed in the client’s OS or browser trust store. This makes the proxy’s interception transparent and prevents browser security warnings.

The SBRS threshold acts as a first, coarse filter—blocking mail from known bad senders before deep scanning. The Anti-Spam scanning sensitivity (often a slider or score weight adjustment) directly controls how aggressively the content filters (like IronPort Anti-Spam) analyze messages. Raising the SBRS block threshold and lowering the scanning sensitivity makes the system more permissive. Lowering the SBRS threshold and increasing sensitivity makes it more aggressive. Tuning these two in tandem is the core method for balancing spam catch rate with false positives.

Configuring a Sender Group within the Inbound Mail Policies allows for granular control. Setting the Spam Action to ‘Skip’ for this specific sender group bypasses spam filtering (including graylisting, reputation, and message filters), while the global Anti-Virus policy, which operates independently, will still scan the messages for malware. This is the most direct and policy-driven method to meet the exact requirement.0