Cisco 300-710 - Securing Networks with Cisco Firewalls

When reconfiguring an existing Cisco FTD from transparent mode to routed mode, an additional action that must be taken to maintain communication between the two network segments is toupdate the IP addressing so that each segment is a unique IP subnet. This is because in routed mode, the FTD device acts as a router hop in the network and requires each interface to be on a different subnet. In transparent mode, the FTD device acts as a layer 2 firewall and does not require different subnets for each interface1.

The other options are incorrect because:

Configuring a NAT rule so that traffic between the segments is exempt from NAT is not necessary to maintain communication between the two network segments. NAT is used to translate IP addresses between different networks, but it does not affect the routing of packets. Moreover, NAT is optional in routed mode and can be disabled if not needed2.

Deploying inbound ACLs on each interface to allow traffic between the segments is not required to maintain communication between the two network segments. ACLs are used to control access to network resources based on source and destination addresses, protocols, and ports. They do not affect the routing of packets. Furthermore, ACLs are optional in routed mode and can be configured as needed3.

Assigning a unique VLAN ID for the interface in each segment is not relevant to maintain communication between the two network segments. VLANs are used to create logical groups of hosts that share the same broadcast domain, regardless of their physical location or connection. They do not affect the routing of packets. Besides, VLANs are not supported in routed mode and can only be used in transparent mode4.

If users report that Cisco Duo 2FA fails when attempting to connect to the VPN on a Cisco Secure Firewall Threat Defense (FTD) device, and the VPN troubleshooting log in FMC shows an error indicating that the Cisco Duo AAA server has been marked as failed, the root cause is likely missing Duo trust certificates on the FTD device. Trust certificates are essential for establishing a secure and trusted connection between the FTD and the Duo authentication service.

Steps:

Obtain the necessary Duo trust certificates.

Install the certificates on the FTD device.

Verify the configuration to ensure that the FTD device can properly communicate with the Duo AAA server.

This resolves the authentication failure by ensuring that the FTD device can trust the Duo server.

To ensure that VoIP traffic in a contact center is not impacted by performance issues after deploying an access control policy on a Cisco Secure Firewall Threat Defense (FTD) device, the engineer should configure the access control rule with the " trust " action. The " trust " action allows traffic to bypass inspection and policy enforcement, ensuring that critical VoIP traffic is not delayed or degraded.

Steps:

In FMC, navigate toPolicies > Access Control > Access Control Policy.

Create a new rule or edit an existing rule.

Set the source and destination for the VoIP traffic.

Set the action to " trust " to ensure the VoIP traffic is not inspected.

By configuring the rule with the " trust " action, the VoIP traffic will be prioritized, maintaining the quality and performance required for the contact center operations.

When capturing traffic on a Cisco FTD device to troubleshoot a connectivity problem, a file type that can be exported for reviewing using a tool built for this type of analysis is PCAP. PCAP stands for Packet Capture and it is a file format used to store network packet data captured from anetwork interface8. PCAP files contain the raw data of network packets, including the headers and payloads of each packet8.

PCAP files are widely used in network analysis and troubleshooting tasks. They enable network administrators, analysts, and researchers to inspect and analyze network traffic for various purposes, such as diagnosing network issues, detecting malicious activity, measuring network performance, and understanding network protocols8. PCAP files can be read by applications that understand that format, such as Wireshark, tcpdump, CA NetMaster, or Microsoft Network Monitor8.

The other options are incorrect because:

NetFlow v9 is not a file type, but a protocol for collecting and exporting information about network flows. A network flow is a sequence of packets that share common attributes such as source and destination IP addresses, ports, and protocols9. NetFlow v9 records contain summary information about network flows, such as start and end times, byte counts, packet counts, and so on9. NetFlow v9 records do not contain the raw data of network packets.

NetFlow v5 is not a file type, but an earlier version of the NetFlow protocol for collecting and exporting information about network flows. NetFlow v5 records contain similar information as NetFlow v9 records, but with fewer fields and less flexibility10. NetFlow v5 records do not contain the raw data of network packets.

IPFIX is not a file type, but a protocol for collecting and exporting information about network flows. IPFIX stands for IP Flow Information Export and it is based on NetFlow v9, but with some extensions and improvements11. IPFIX records contain similar information as NetFlow v9 records, but with more fields and more flexibility11. IPFIX records do not contain the raw data of network packets.