Securing Networks

Question 1

What’s the difference between standard ACL and Extended ACL

Answer 1

Standard ACL 1-99 only looks at source address for traffic filtering, while Extended ACL looks at both source address and destination address for traffic filtering

Question 2

What’s the implicit condition of an ACL

Answer 2

there is an implicit deny any at the bottom of any ACL

Question 3

What protocol is HTTP under

Answer 3

TCP

Question 4

What protocol is HTTP under

Answer 4

TCP

Question 5

What’s the max number of ACLs on an interface

Answer 5

one inward max one outward max

Question 6

How is an ACL executed

Answer 6

Lower number to higher number, more specific should be placed at the top

Question 7

Place a range of ports in an unused VLAN

Answer 7

create vlan 999
int range fa 0/1 - 24
switchport access?

Question 8

What is the IEEE standard for a VLAN

Answer 8

IEEE 802.1q

Question 9

What is a native VLAN

Answer 9

A VLAN on a IEEE 802.1q trunk whose frames are not tagged

Question 10

What is a typical VLAN port

Answer 10

Port 1

Question 11

What does AAA stand for

Answer 11

Authentication, Authorization, Accounting

Question 12

What are the three components of 802.1x

Answer 12

Supplicant: asks permission for network access
Authenticator
Authentication Server
1. Authenticator sends challenge
2. Supplicant sends Username/Password
3. Authentication Server sends Authorization

Question 13

What is the difference between TACACS+ vs RADIUS

Answer 13

TACACS+ is a Cisco proprietary protocol, Separates A’s into separate tasks, 2 way challenge, encrypts whole packet, uses TCP
RADIUS uses UDP, all A’s in one function, one way challenge, only encrypts password

Question 14

What is DHCP Snooping

Answer 14

When we allow a switch port to reject packets if that port is set to an untrusted state

Question 15

What is an ip helper-address for?

Answer 15

If the DHCP server is in a different VLAN compared to where the router or host is, it can set the helper-address to the address of the DHCP server

Question 16

What are the 4 stages of a DHCP exchange

Answer 16

DORA where Discover Offer Request Acknowledgement

Question 17

Configure DHCP snooping

Answer 17

ip dhcp snooping 
ip dhcp snooping (vlan)
ip dhcp snooping limit
interface:
ip dhcp snooping trust

Question 18

What’s the difference between interface down and line protocol down

Answer 18

interface = layer 1, line protocol = layer 2
Interface down = cable faulty or not connected on one or both ends
Line Protocol down = port must be shut down from other side or connection issue