Exam 200-125 topic 1 question 68 discussion

SIMULATION -
A corporation want to add security to its network. The requirements are:
- Host C should be able to use a web browser (HTTP) to access the Finance Web Server.
- 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.
- All hosts in the Core and on local LAN should be able to access the Public Web Server.
You have been tasked to create and apply a numbered access list to a single outbound interface. This access list can contain no more than three statements that meets these requirements.
Access to the router CLI can be gained by clicking on the appropriate host.
1. All passwords have been temporarily set to "cisco".
2. The core connection uses an IP address of 192.168.228.65.
3. The computers in the hosts LAN been assigned addresses of 192.168.40.1 192.168.40.254.
- host A 192.168.40.1
- host B 192.168.40.2
- host C 192.168.40.3
- host D 192.168.40.4
4. The Finance Web Server has been assigned an addresses of 172.22.135.17.
5. The Public Web Server in the Server LAN has been assigned an addresses of 172.22.135.18.
Note: - You may need to scroll this window and the problem statement window.
- Click on picture of cost connected to the specified router and select the CiscoTerminal option to configure the router. If you select the wrong host, click on the show topology button and select a different host.
- To access a host, simply click on picture of host that you want to use and configure it. Certain hosts have dotted lines that represent the serial "console" cables.
- The help command does not display all commands of the help system. The help supports the first level of help system and selected lower layers.

Suggested Answer: See the solution below
(you may enter "cisco" as it passwords here)

Corp1>enable -
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 -

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 cant 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):

Modification 2 (Mod 2):


Modification 3 (Mod 3):2 -

Modification 4 (Mod 4):

* 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: Dont 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)