CISCO CCNA Exam – Q286

Refer to the exhibit.
CISCO CCNA Exam – Q286

The following commands are executed on interface fa0/1 of 2950Switch.
2950Switch(config-if)# switchport port-security
2950Switch(config-if)# switchport port-security mac-address sticky
2950Switch(config-if)# switchport port-security maximum 1
The Ethernet frame that is shown arrives on interface fa0/1. What two functions will occur when this frame is received by 2950Switch? (Choose two.)

A. The MAC address table will now have an additional entry of fa0/1 FFFF.FFFF.FFFF.
B. Only host A will be allowed to transmit frames on fa0/1.
C. This frame will be discarded when it is received by 2950Switch.
D. All frames arriving on 2950Switch with a destination of 0000.00aa.aaaa will be forwarded out fa0/1.
E. Hosts B and C may forward frames out fa0/1 but frames arriving from other switches will not be forwarded out fa0/1.
F. Only frames from source 0000.00bb.bbbb, the first learned MAC address of 2950Switch, will be forwarded out fa0/1.

Correct Answers: B,D

Explanation:
The configuration shown here is an example of port security, specifically port security using sticky addresses. You can use port security with dynamically learned and static MAC addresses to restrict a port’s ingress traffic by limiting the MAC addresses that are allowed to send traffic into the port. When you assign secure MAC addresses to a secure port, the port does not forward ingress traffic that has source addresses outside the group of defined addresses. If you limit the number of secure MAC addresses to one and assign a single secure MAC address, the device attached to that port has the full bandwidth of the port.
Port security with sticky MAC addresses provides many of the same benefits as port security with static MAC addresses, but sticky MAC addresses can be learned dynamically.
Port security with sticky MAC addresses retains dynamically learned MAC addresses during a link-down condition.

CISCO CCNA Exam – Q211

Refer to the exhibit.
CISCO CCNA Exam – Q211

Statements A, B, C, and D of ACL 10 have been entered in the shown order and applied to interface E0 inbound, to prevent all hosts (except those whose addresses are the first and last IP of subnet 172.21.1.128/28) from accessing the network. But as is, the ACL does not restrict anyone from the network. How can the ACL statements be re-arranged so that the system works as intended?

A. ACDB
B. BADC
C. DBAC
D. CDBA

Correct Answer: D
< Explanation:
Routers go line by line through an access list until a match is found and then will not look any further, even if a more specific of better match is found later on in the access list.
So, it it best to begin with the most specific entries first, in this cast the two hosts in line C and D. Then, include the subnet (B) and then finally the rest of the traffic (A).