Cisco 300-720 - Securing Email with Cisco Email Security Appliance (300-720 SESA)

User and routing are two query types that are available when an LDAP profile is configured on Cisco ESA. User queries are used to validate end-user credentials, such as for Spam Quarantine End-User Authentication or SMTP Authentication. Routing queries are used to determine the destination mail server for a recipient, such as for Mail Flow Policies or Delivery Methods.

References: User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway, page 10-7.

A TXT record is a type of DNS record that contains arbitrary text data that can be used for various purposes such as verification, configuration, or authentication. A TXT record can contain the DKIM public key per RFC 6376, which is used to verify the digital signature of an email message generated by the DKIM private key of the sender domain.

The other options are not valid because:

A. A CNAME record is a type of DNS record that maps an alias name to a canonical name or another alias name. It does not contain any DKIM public key information.

B. An AAAA record is a type of DNS record that maps a hostname to an IPv6 address. It does not contain any DKIM public key information.

D. A PTR record is a type of DNS record that maps an IP address to a hostname, which is the reverse of an A or AAAA record. It does not contain any DKIM public key information.

Secure unsubscribe option for end users. Mimicking an unsubscribe option is a popular phishing technique. For this reason, the end users are generally wary of clicking unknown unsubscribe links. For such scenarios, the cloud-based Unsubscribe Service extracts the original unsubscribe URI, checks the reputation of the URI, and then performs the unsubscribe process on behalf of the end user. This protects end users from malicious threats masquerading as unsubscribe links. https://www.cisco.com/c/en/us/td/docs/security/esa/esa14-2-1/User_Guide/b_ESA_Admin_Guide_14-2-1/b_ESA_Admin_Guide_12_1_chapter_01110.html#id_101033

Configuring the outbound firewall rule to permit traffic on port 3237 is the additional action that resolves the issue. AMP file reputation is a feature that allows Cisco ESA to check files attached to messages against a cloud-based database of known malicious files and apply appropriate actions, such as block, deliver, or quarantine.

By default, AMP file reputation uses TCP port 3237 to communicate with the cloud-based database. If this port is blocked by a firewall, AMP file reputation will not work properly.

To resolve this issue, the administrator can configure the outbound firewall rule to permit traffic on port 3237 from Cisco ESA.

The other options are not valid actions to resolve the issue, because they do not affect the port used by AMP file reputation.

References: [User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway], page 7-5 and page 7-6.