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Network Security - Networking MCQ Questions and answers | Technical Aptitude

Learn Network Security mcq questions and answers with easy and logical explanations for various competitive examination, interview and entrance test Page-2 section-1

11
You configure the following access list: 
access-list 110 deny tcp 10.1.1.128 0.0.0.63 any eq smtp
access-list 110 deny tcp any eq 23
int ethernet 0
ip access-group 110 out
What will the result of this access list be?
Discuss
Answer & Solution
Answer: Option D
Solution:
If you add an access list to an interface and you do not have at least one permit statement, then you will effectively shut down the interface because of the implicit deny any at the end of every list.
12
You want to create a standard access list that denies the subnet of the following host: 172.16.198.94/19. Which of the following would you start your list with?
Discuss
Answer & Solution
Answer: Option A
Solution:
First, you must know that a /19 is 255.255.224.0, which is a block size of 32 in the third octet. Counting by 32, this makes our subnet 192 in the third octet, and the wildcard for the third octet would be 31 since the wildcard is always one less than the block size.
13
If you wanted to deny all Telnet connections to only network 192.168.10.0, which command could you use?
Discuss
Answer & Solution
Answer: Option C
Solution:
The extended access list ranges are 100-199 and 2000-2699, so the access-list number of 100 is valid. Telnet uses TCP, so the protocol TCP is valid. Now you just need to look for the source and destination address. Only the third option has the correct sequence of parameters. Answer B may work, but the question specifically states "only" to network 192.168.10.0, and the wildcard in answer B is too broad.
14
Which router command allows you to view the entire contents of all access lists?
Discuss
Answer & Solution
Answer: Option C
Solution:
The show access-lists command will allow you to view the entire contents of all access lists, but it will not show you the interfaces to which the access lists are applied.
15
Which of the following access lists will allow only HTTP traffic into network 196.15.7.0?
Discuss
Answer & Solution
Answer: Option A
Solution:
The first thing to check in a question like this is the access-list number. Right away, you can see that the second option is wrong because it is using a standard IP access-list number. The second thing to check is the protocol. If you are filtering by upper-layer protocol, then you must be using either UDP or TCP; this eliminates the fourth option. The third and last answers have the wrong syntax.
16
Which of the following are valid ways to refer only to host 172.16.30.55 in an IP access list? 1. 172.16.30.55 0.0.0.255 2. 172.16.30.55 0.0.0.0 3. any 172.16.30.55 4. host 172.16.30.55 5. 0.0.0.0 172.16.30.55 6. ip any 172.16.30.55
Discuss
Answer & Solution
Answer: Option B
Solution:
The wildcard 0.0.0.0 tells the router to match all four octets. This wildcard format alone can be replaced with the host command.
17
If you wanted to deny FTP access from network 200.200.10.0 to network 200.199.11.0 but allow everything else, which of the following command strings is valid?
Discuss
Answer & Solution
Answer: Option D
Solution:
Extended IP access lists use numbers 100-199 and 2000-2699 and filter based on source and destination IP address, protocol number, and port number. The last option is correct because of the second line that specifies permit ip any any. (I used 0.0.0.0 255.255.255.255, which is the same as the any option.) The third option does not have this, so it would deny access but not allow everything else.
18
Which of the following series of commands will restrict Telnet access to the router?
Discuss
Answer & Solution
Answer: Option C
Solution:
Telnet access to the router is restricted by using either a standard or extended IP access list inbound on the VTY lines of the router. The command access-class is used to apply the access list to the VTY lines.
19
Which of the following commands connect access list 110 inbound to interface ethernet0?
Discuss
Answer & Solution
Answer: Option C
Solution:
To place an access list on an interface, use the ip access-group command in interface configuration mode.