ACL Network Security & Traffic Filtering 5

Question 1

A Dynamic ACL (lock-and-key ACL) requires users to do what before gaining network access?

Accepted Answer

Authenticate via Telnet or SSH to trigger a temporary permit entry

Answer

Configure a VPN tunnel

Answer

Register their MAC address with the DHCP server

Answer

Enable 802.1X on their workstation

Question 2

What is the effect of applying an ACL to a VTY line with 'access-class 10 in'?

Accepted Answer

It restricts which IP addresses can establish a Telnet or SSH management session to the router

Answer

It filters all routed traffic through the router

Answer

It encrypts all VTY sessions

Answer

It sets a timeout for idle VTY sessions

Question 3

Which of the following is NOT a valid reason to use ACLs?

Accepted Answer

Encrypting traffic between two routers

Answer

Filtering traffic between network segments

Answer

Controlling which routes are advertised in routing protocols

Answer

Restricting remote management access to network devices

Question 4

An administrator sees 'access-list 1 permit 0.0.0.0 255.255.255.255' in the config. What traffic does this match?

Accepted Answer

All IP traffic from any source address

Answer

Only traffic from the host 0.0.0.0

Answer

Only traffic destined to the broadcast address

Answer

No traffic, as this is an invalid ACE

Question 5

What is the significance of ACL sequence numbers in named ACLs on Cisco IOS?

Accepted Answer

They allow specific ACEs to be inserted between existing entries or deleted individually

Answer

They determine the priority of the ACL over other ACLs on the same interface

Answer

They limit how many packets each ACE can match

Answer

They define the time-to-live for dynamic ACL entries

Question 6

A 'permit ip any any' rule exists in an ACL but traffic is still being blocked. What is the most likely cause?

Accepted Answer

A more specific deny entry appears before the permit statement in the ACL

Answer

The router's CPU is overloaded

Answer

The 'ip any any' syntax is invalid and ignored

Answer

The interface has no ACL applied

Question 7

Which show command displays the hit counts for each ACE in an ACL to verify it is matching traffic?

Accepted Answer

show access-lists

Answer

show ip interface brief

Answer

show running-config

Answer

show ip route