Your design plan includes mutual redistribution of two OSPF networks at multiple locations, with connectivity to all locations in both networks. How is this accomplished without creating routing loops?

Which option describes a design benefit of root guard?

You are designing an IEEE 802.1X solution for a customer, where the network supports a large number of IP phones and printers.
You plan to configure MAC address bypass for the phones and printers. What is your primary design and security concern?

After the recent implementation of a new design that incorporated GRE tunnels into the network, the network operations staff is seeing the following syslog message in multiple routes on the network -

From a design perspective, what was not taken into account prior to implementing the solution?

Your network operations team is deploying Access Control Lists (ACLs) across your Internet gateways.
They wish to place an ACL inbound on the Internet gateway interface facing the core network (the "trusted" interface). Which one of these addresses would the ACL need for traffic sourced from the inside interface, to match the source address of the traffic?