Enterprise Routing and Switching, Specialist (JNCIS-ENT): JN0-347

Correct Answer: BC

B: Dynamic ARP inspection (DAI) prevents Address Resolution Protocol (ARP) spoofing attacks. ARP requests and replies are compared against entries in the DHCP snooping database, and filtering decisions are made on the basis of the results of those comparisons.

C: IP source guard mitigates the effects of IP address spoofing attacks on the Ethernet LAN. With IP source guard enabled, the source IP address in the packet sent from an untrusted access interface is validated against the SourceDSN MAC address in the DHCP snooping database. The packet is forwarded if the source IP-MAC binding is valid; if the binding is not valid, the packet is discarded. You enable IP source guard on a VLAN. EX Series switches support IPv6 source guard also.

Correct Answer: A

Configuring Routing Between VLANs on One Switch to segment traffic on a LAN into separate broadcast domains, you create separate virtual LANs (VLANs). Of course, you also you want to allow these employees to communicate with people and resources in other VLANs. To forward packets between VLANs you normally you need a router that connects the VLANs. However, you can accomplish this on a Juniper Networks switch without using a router by configuring an integrated routing and bridging (IRB) interface (also known as a routed VLAN interface-- or RVI-- in versions of Junos OS that do not support Enhanced Layer 2 Software).

Correct Answer: BD

In IS-IS, deterministic DIS election makes the possibility of predicting the router that will be elected as DIS

from the same set of routers.

The router advertising the numerically highest priority wins, with numerically highest MAC address, also

called a Subnetwork Point of Attachment (SNPA), breaking the tie.