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CCNA Access List Sim 2

February 15th, 2014 Go to comments

Question

access_list_sim2.jpg

Answer and Explanation

(Note: If you are not sure how to use access-list, please check out my access-list tutorial at: http://www.pentagona.com/?exams=access-list-tutorial, also some modifications about the access-list have been reported so you should read the “Some modifications” section at the end of this question to understand more. You can also download this sim to practice (open with Packet Tracer) here: http://www.pentagona.com/?exams=download/9tut.com_Access-list_sim2.zip

Corp1>enable (you may enter “cisco” as it passwords here)

We should create an access-list and apply it to the interface which is connected to the Server LAN because it can filter out traffic from both Sw-2 and Core networks. The Server LAN network has been assigned addresses of 172.22.242.17 – 172.22.242.30 so we can guess the interface connected to them has an IP address of 172.22.242.30 (.30 is the number shown in the figure). Use the “show running-config” command to check which interface has the IP address of 172.22.242.30.

Corp1#show running-config

access_list_sim_show_running.jpg

We learn that interface FastEthernet0/1 is the interface connected to Server LAN network. It is the interface we will apply our access-list (for outbound direction).

Corp1#configure terminal

Our access-list needs to allow host C – 192.168.33.3 to the Finance Web Server 172.22.242.23 via web (port 80)

Corp1(config)#access-list 100 permit tcp host 192.168.33.3 host 172.22.242.23 eq 80

Deny other hosts access to the Finance Web Server via web

Corp1(config)#access-list 100 deny tcp any host 172.22.242.23 eq 80

All other traffic is permitted

Corp1(config)#access-list 100 permit ip any any

Apply this access-list to Fa0/1 interface (outbound direction)

Corp1(config)#interface fa0/1
Corp1(config-if)#ip access-group 100 out

Notice: We have to apply the access-list to Fa0/1 interface (not Fa0/0 interface) so that the access-list can filter traffic coming from both the LAN and the Core networks. If we apply access list to the inbound interface we can only filter traffic from the LAN network.

In the exam, just click on host C to open its web browser. In the address box type http://172.22.242.23 to check if you are allowed to access Finance Web Server via HTTP or not. If your configuration is correct then you can access it.

Click on other hosts (A, B and D) and check to make sure you can’t access Finance Web Server from these hosts.

Finally, save the configuration

Corp1(config-if)#end
Corp1#copy running-config startup-config

(This configuration only prevents hosts from accessing Finance Web Server via web but if this server supports other traffic – like FTP, SMTP… then other hosts can access it, too.)

Notice: You might be asked to allow other host (A, B or D) to access the Finance Web Server so please read the requirement carefully.

Some modifications (mods):

Modification 1 (Mod 1):

permit host B from accessing finance server access-list 100 permit ip host 192.168.33.2 host 172.22.242.23
deny host B from accessing other servers (not the whole network) access-list 100 deny ip host 192.168.33.2 172.22.242.16 0.0.0.15
permit everything else access-list 100 permit ip any any

Modification 2 (Mod 2):

Only allow Host C to to access the financial server access-list 100 permit ip host 192.168.33.3 host 172.22.242.23
Not allow anyone else in any way communicate with the financial server access-list 100 deny ip any host 172.22.242.23
Allow all other traffic access-list 100 permit ip any any

Modification 3 (Mod 3):

– Host C should be able to use a web browser(HTTP)to access the Finance Web Server access-list 100 permit tcp host 192.168.33.3 host 172.22.242.23 eq 80
– Other types of access from host C to the Finance Web Server should be blocked
– All access from hosts in the Core or local LAN to the Finance Web Server should be blocked
access-list 100 deny ip any host 172.22.242.23
(because the requirement says we can not use more than 3 statements so we have to use “any” here for the hosts in the Core and hosts in local LAN)
– All hosts in the Core and local LAN should be able to access the Public Web Server * access-list 100 permit ip any host
(If the question asks this, surely it has to give you the IP of Public Web Server) but in the exam you should use “access-list 100 permit ip any any”

Modification 4 (Mod 4):

Host C should be able to use a web browser to access the financial web server access-list 100 permit tcp host 192.168.33.3 host 172.22.242.23 eq 80
Other types of access from host C to the finance web server should be blocked access-list 100 deny ip host 192.168.33.3 host 172.22.242.23
All hosts in the core and on the local LAN should be able to access the Public web server * access-list 100 permit ip any host
(The IP of Public Web Server will surely be given in this question) but in the exam you should use “access-list 100 permit ip any any”

* There are some reports about the command of “All hosts in the core and on the local LAN should be able to access the Public web server” saying that the correct command should be “access-list 100 permit ip any any”, not “access-list 100 permit ip any host (IP of Public Web Server)”. Although I believe the second command is better but maybe you should use the first command “access-list 100 permit ip any any” instead as some reports said they got 100% when using this command (even if the question gives you the IP address of Public Web Server). It is a bug in this sim.

(Note: Don’t forget to apply this access list to the suitable interface or you will lose points
interface fa0/1
ip access-group 100 out

And in the exam, they may slightly change the requirements, for example host A, host B instead of host C… so make sure you read the requirement carefully and use the access-list correctly)

I created this sim in Packet Tracer v5.2.1 so you can practice with it. You will need new version of Packet Tracer to open it (v5.1+).

accesslist_sim2_packet_tracer.jpg

Download this sim here

Notice: After typing the commands above, if you make a “ping” from other hosts (PC0, PC1, PC3) then PC4 (Finance Web Server) can still reply because we just filter HTTP traffic, not ICMP traffic. To generate HTTP traffic, select “Web Browser” in the “Desktop” tab of these PCs. When a web browser opens, type the IP address of Finance Web Server and you can see how traffic flows in Simulation Mode.

accesslist2_test_http.jpg

And notice that in the initial configuration of this sim the Core network can ping Finance Web Server. We have to create an access-list that can filter this traffic too.

Comments
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  1. SHASHI
    February 14th, 2018

    Where can i get the question for ACL sim ?

  2. TweeezY
    February 15th, 2018

    Passed exam today all the question and labs from 9tut :ACL+OSPF+EIGRP+4 DRAG

  3. @ANONYMOUS-
    February 15th, 2018

    got exact question in exam. only ip addresses lil bit chnaged. passed with 9xx marks

  4. lagrossebite
    February 23rd, 2018

    Just had my CCNA thanks to 9tut, got 873/1000, ACL lab2 mod3

  5. Raju
    February 27th, 2018

    Hi guys any latest dumps for 300-101.

    my exam is in next month.

    this is my email id :- raj09028 at gmail dot com

    thank you

  6. Raju
    February 27th, 2018

    Hi guys any latest dumps for 200-125

    my exam is in next month.

    this is my email id :- raj09028 at gmail dot com

    thank you

  7. Mr D
    March 8th, 2018

    1:N is for redundant master for a swt stack…

  8. Modu
    March 17th, 2018

    Any latest dumps for the CCNA exams

  9. Dave
    March 17th, 2018

    Guys, I will be taking the CCNA 200-125 exams end of this month. Can someone send me the latest dumps on my email davesk*41* @*gmail dot com. Please remove the start to get the email

  10. Trusted…Tested…Dumps for Free
    March 17th, 2018

    Latest Dumps inside:
    mediafire.com/folder/qfip8azi6e8yq/Latest%20Dumps

  11. Anonymous
    March 18th, 2018

    The command “access-list 100 permit ip any host” will block the access to the DNS server (apply a numbered access-list with no more than three statements), so the correct command is “access-list 100 permit ip any any”.

  12. ethan
    March 19th, 2018

    Passed CCNA today.

    Got few news questions . The one that i remembered are as below :

    1. https://www.google.com/search?q=verify+nic+operation+drag+and+drop&tbm=isch&source=lnms&sa=X&ved=0ahUKEwjuvqyzwfjZAhXMrY8KHXLjDU8Q_AUICygC&biw=1910&bih=878&dpr=1#imgrc=5yEAMOSR63Hp8M:

    2. It will asked why choose chassis aggregation instead of stacking switches .

    3. I got 2 LAB ( ACL + IPV6 OSPF )

    4. Multiples choice from LAB ( GRE + EIGRP + OSPF ) — Please take note the answer is not the same anymore because they have tweak all the questions with different scenarios. Please make sure you understand how to use all the output commands to get the answers .

  13. Tom
    March 20th, 2018

    hi i have a question can’t we do the command:
    router(config):ip access-list extended 100
    router(config-ext-nacl):permit tcp host 192.168.33.3 host 172.22.242.23 eq 80
    router(config-ext-nacl):deny tcp any host 172.22.242.23 eq 80
    router(config-ext-nacl):permit ip any any

  14. Tom
    March 20th, 2018

    also in mod 3 and 4 if we use the command permit ip any any do we lose points instead of the other command?

  15. John D. Ngowi
    March 21st, 2018

    Tom with
    router(config-ext-nacl):deny tcp any host 172.22.242.23 eq 80

    This means that it will deny only tcp (http) and allow/permit tcp (FTP,SSH,TELNET,SMTP,DNS,POPv3, IMAP4 and HTTPS) and permit other protocols ie UDP (DNS Clients eMails,TFTP) ICMP (echo and echo reply)

  16. Tom
    March 22nd, 2018

    John But isn’t that the requirement of the question that no one should have access to the web server except for host c and by the way wont it deny other protocols like udp due to the implecid deny statement at the end unless when we give the command permit ip any any at the end then it wont deny

  17. alex
    March 25th, 2018

    The netmask of the servers in this packet tracer sim is not correct.
    some of the servers have 255.255.255.240.0 and others have 255.255.255.240
    I believe this should be 255.255.255.240 to have a smaller range and simulate a DMZ zone with some public addresses.

  18. kamal
    March 28th, 2018

    i need to answer the sim labs with my self like trying to access the host and do show commands..can anyone enlighten me pls

  19. Favio
    March 29th, 2018

    Hi, can send me only labs for my exam, my exam is the next weed and i need practice
    exercises.

    Thanks!

  20. Favio
    March 29th, 2018

    Hi, can send me only labs for my exam, my exam is the next weed and i need practice
    exercises.

    pd:
    my email: {email not allowed}

    Thanks!

  21. Aman
    April 3rd, 2018

    What should be the last statement , permit ip any any or permit ip host any

  22. Sid
    April 3rd, 2018

    Hello Everyone.

    Just passed my exam today. This sim and VLAN Sim was there to configure and other GRE Multilink sim, OSPF Neighbor sim and Access List Sim 1 was there to troubleshoot. A bit of configurations are changed you must be present there with mind to solve these sims. Few of Drag and Drops were new in exam.

    Thanks

  23. Aman
    April 11th, 2018

    Passed exam with 964/1000 . I got this sim

  24. Anonymous
    April 18th, 2018

    i am unable to find/see Questions of ACL Sim2 please and answer and explanation can read (question need)

  25. Tom
    April 20th, 2018

    hi in some questions of this sim the ip address of the corp1 router serial 1/0 connecting to the core router is misconfigured (192.168.44.1/30) when it should be 198.18.196.65/30 do we have to recorrect it by assigning the right ip in the serial 1/0 of ther corp1 router if so do we have to do the no ip address command and then give the correct ip since the core ip address is 198.18.196.66/30

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