Cisco Updated 350-701 Exam Questions and Answers by cara

 To configure the Cisco ASA via ASDM for SNMPv3, the administrator needs to perform two main tasks: specify an SNMP user group and add an SNMP USM entry. An SNMP user group defines the access level and security model for a group of SNMP users. An SNMP USM entry defines the authentication and encryption parameters for a specific SNMP user. These two tasks are required for SNMPv3 because it uses a user-based security model (USM) that provides secure access to the MIB objects. SNMPv3 does not use a community string, which is a shared password used by SNMPv1 and SNMPv2c. The SNMP manager and UDP port are optional parameters that can be specified to customize the SNMP communication. The SNMP host access entry is also optional and can be used to restrict the access of SNMP hosts to specific interfaces or networks. References :=

Some possible references are:

SNMP Configuration, Verification and Troubleshooting on ASA

How to configure SNMP v3 on Cisco Switch, Router, ASA, Nexus

SNMP Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches)

Explanation

CoA Messages are sent on two different udp ports depending on the platform. Cisco standardizes on UDP port

1700, while the actual RFC calls out using UDP port 3799.

DNS tunneling is a technique that uses the DNS protocol to exfiltrate data or establish command and control channels between a compromised host and an attacker-controlled server. DNS tunneling can bypass network security controls that allow outbound DNS traffic without inspection or filtering. To stop DNS tunneling, two recommended approaches are:

Enforce security over port 53. This means applying firewall rules, access control lists, or other mechanisms to restrict outbound DNS traffic to only authorized DNS servers and domains. Additionally, DNS traffic should be inspected and analyzed for anomalies, such as unusually large or frequent queries, non-standard encoding, or suspicious domains. This can help detect and block DNS tunneling attempts.

Use Cisco Umbrella. Cisco Umbrella is a cloud-based security service that provides DNS security, web filtering, and threat intelligence. Cisco Umbrella can prevent DNS tunneling by blocking malicious domains, enforcing policies based on content categories, and applying machine learning to identify and stop emerging threats. Cisco Umbrella can also provide visibility and reporting on DNS activity and security events.

References :=

Implementing and Operating Cisco Security Core Technologies (SCOR) v1.0, Module 5: Securing the Cloud, Lesson 5.2: DNS Security

What Is DNS Tunneling? - Palo Alto Networks

An Introduction to DNS Tunneling Detection & Data Exfiltration via DNS - Vercara