300-410 Exam Dumps - Implementing Cisco Enterprise Advanced Routing and Services (300-410 ENARSI)

Explanation

The DHCPv6 Guard feature blocks reply and advertisement messages that come from unauthorized

DHCP servers and relay agents.

Packets are classified into one of the three DHCP type messages. All client messages are always

switched regardless of device role. DHCP server messages are only processed further if the device role

is set to server. Further processing of server messages includes DHCP server advertisements (for

source validation and server preference) and DHCP server replies (for permitted prefixes).

If the device is configured as a DHCP server, all the messages need to be switched, regardless of the

device role configuration.

Explanation

The problem is “SSH traffic does not match in the ACL” and “CoPP policy is applied for receiving SSH

traffic from the WAN interface” so we should apply CoPP on the control plane interface instead.

The Destination Guard feature helps in minimizing denial-of-service (DoS) attacks. It performs

address resolutions only for those addresses that are active on the link, and requires the FHS binding

table to be populated with the help of the IPv6 snooping feature.The feature enables the filtering of

IPv6 traffic based on the destination address, and blocks the NDP resolution for destination addresses

that are not found in the binding table. By default, the policy drops traffic coming for an unknown

destination.

 The Label Distribution Protocol (LDP) plays a crucial role in MPLS (Multiprotocol Label Switching) networks. It enables label switch routers (LSRs) to exchange label binding information, which is essential for supporting hop-by-hop forwarding in an MPLS network1.

LDP establishes LSPs (Label Switched Paths) that follow the existing IP routing table2. This process is particularly well-suited for establishing a full mesh of LSPs between all of the routers on the network2.

When a packet arrives at a router in an MPLS network, the router looks at the incoming label, looks up the label in a table, and then forwards the packet to the next hop1. This method of label distribution is also called hop-by-hop forwarding1.

References:

• MPLS LDP (Label Distribution Protocol) - NetworkLessons.com
• MPLS Label Distribution Protocol (LDP) - Cisco
• What is Label Distribution Protocol (LDP)? - Metaswitch
• Label Distribution Protocol - Wikipedia
• What is MPLS LDP in networking? – CCNA-Classes

IPv6 Source Guard uses the IPv6 First-Hop Security Binding Table to drop traffic from unknown

sources or bogus IPv6 addresses not in the binding table. The switch also tries to recover from lost

address information, querying DHCPv6 server or using IPv6 neighbor discovery to verify the source

IPv6 address after dropping the offending packet(s).